Rapid-recall takeaways distilled from the MRCPsych Paper A question bank, grouped by specialty. One pearl per high-frequency concept. Use it for last-pass revision alongside questions, not as a replacement for them.
400 pearls · 5 specialties · Generated 6 November 2026
Clinical Psychopharmacology
80 high-yield facts
Citalopram/escitalopram have the weakest CYP450 inhibition among SSRIs - choose them when minimising drug interactions is the priority.
Lithium has the narrowest therapeutic index in psychiatry - therapeutic range 0.4-1.0 mmol/L with toxicity above 1.5 mmol/L requiring regular monitoring.
Acamprosate modulates glutamate/NMDA signalling to reduce craving in alcohol dependence - it restores excitatory/inhibitory balance disrupted by chronic alcohol use.
Benzodiazepines increase the frequency of GABA-A chloride channel opening (positive allosteric modulation) - barbiturates increase the duration and can directly open the channel.
Acamprosate modulates NMDA glutamate receptors to restore excitatory/inhibitory balance - start after detox, continue for 1 year; renally eliminated, contraindicated in severe renal impairment.
TCAs non-selectively inhibit serotonin and noradrenaline reuptake but also block muscarinic, histaminergic, and alpha-1 receptors causing extensive side effects.
SSRIs cause GI side effects through 5-HT3/5-HT4 stimulation in the gut - nausea and diarrhoea usually resolve within 1-2 weeks of treatment.
Loading dose = Vd × Cp / F - it rapidly achieves target levels, while maintenance dose is determined by clearance.
Quetiapine is a primary CYP3A4 substrate - its levels are significantly affected by CYP3A4 inhibitors and inducers including carbamazepine and ketoconazole.
SSRIs cause hyponatraemia via SIADH - elderly women are most at risk, particularly in the first month of treatment.
Lithium augmentation has robust RCT evidence for treatment-resistant depression - NICE recommends it after two adequate antidepressant failures.
Competitive antagonism produces a parallel rightward shift of the dose-response curve with preserved Emax - the effect is surmountable by increasing agonist concentration.
ACE inhibitors reduce aldosterone, causing sodium depletion and compensatory proximal tubular lithium reabsorption - monitor lithium closely and consider alternative antihypertensives.
Mirtazapine is more sedating at 15mg than 30mg - H1 blockade dominates at low doses while noradrenergic activation counteracts sedation at higher doses.
Clonus (spontaneous, inducible, or ocular) is the hallmark of serotonin syndrome in the Hunter Criteria - it distinguishes SS from NMS where rigidity predominates.
Irreversible MAOIs require a 2-week washout before starting serotonergic drugs - new MAO enzyme must be synthesised as the original enzyme is permanently inactivated.
Continue antidepressants for at least 6 months after remission of first episode - consider 2+ years for recurrent depression. Always taper gradually.
IV sodium bicarbonate is the key treatment for TCA overdose with QRS >100ms - it overcomes sodium channel blockade through sodium loading and alkalinisation.
Norfluoxetine inhibits CYP2D6 for weeks after stopping fluoxetine - start TCAs at low dose and monitor levels when switching from fluoxetine.
Clozapine achieves therapeutic response at only 40-60% D2 occupancy - its unique efficacy involves non-D2 mechanisms and fast D2 dissociation.
Paroxetine's short half-life and anticholinergic properties make it the SSRI most associated with discontinuation symptoms - taper slowly using NICE guidelines.
SSRI sexual dysfunction is mediated by 5-HT2A/2C stimulation inhibiting dopaminergic pathways - mirtazapine and agomelatine have lower rates.
Vortioxetine combines SERT blockade with 5-HT1A agonism and 5-HT3/5-HT7 antagonism - this multimodal action may benefit cognition and reduce sexual dysfunction.
Z-drugs preferentially bind the alpha-1 GABA-A subunit mediating sedation - despite theoretical selectivity, dependence risk is similar to benzodiazepines.
Sympathomimetic features (hyperthermia, tachycardia, mydriasis) distinguish stimulant psychosis from primary psychosis - treat with benzodiazepines first, not antipsychotics.
Pregabalin binds the α2δ subunit of voltage-gated calcium channels - it does not act on GABA receptors despite its name and structural similarity to GABA.
CYP2D6 converts codeine to morphine - fluoxetine potently inhibits CYP2D6, blocking this conversion and rendering codeine ineffective.
MAO-A preferentially metabolises serotonin and noradrenaline; MAO-B metabolises phenylethylamine - this explains MAOI drug selection for depression versus Parkinson's.
First-order = constant fraction eliminated with constant half-life; zero-order = constant amount eliminated with no true half-life.
TCAs cause severe anticholinergic toxicity in overdose combined with sodium channel blockade and alpha-1 blockade - limit prescription quantities in at-risk patients.
Trazodone is sedating due to potent 5-HT2A and H1 antagonism at low doses - warn patients about priapism and use cautiously due to alpha-1 blockade.
Lorazepam 1mg ≈ diazepam 10mg - convert to diazepam for smooth tapering using the Ashton Manual or Maudsley approach.
Gastric emptying rate is the primary determinant of oral drug absorption rate - anticholinergic drugs and food generally delay emptying and absorption.
Thiazides cause sodium depletion leading to compensatory proximal tubular lithium reabsorption - monitor lithium levels closely and consider dose reduction.
Lithium inhibits inositol monophosphatase, depleting the phosphatidylinositol signalling pathway in overactive neurons - the inositol depletion hypothesis.
EC50 is the drug concentration producing 50% of maximal response - it measures potency and is read from the midpoint of the sigmoid dose-response curve.
Paroxetine is the SSRI most associated with cardiac septal defects in the first trimester - sertraline is generally preferred in pregnancy.
IM procyclidine 5mg is first-line for acute dystonia - it corrects the cholinergic excess caused by D2 blockade in the nigrostriatal pathway.
Chronic SSRI treatment desensitises presynaptic 5-HT1A autoreceptors - this removes negative feedback and enhances serotonin release, explaining the 2-4 week therapeutic delay.
Receptor reserve means maximum response is achieved at fractional receptor occupancy - this explains why EC50 is less than Kd and has implications for tolerance and antipsychotic dosing.
SSRIs initially worsen anxiety through acute 5-HT2C stimulation - start at half dose in anxiety disorders and consider short-term benzodiazepine cover.
LOT (Lorazepam, Oxazepam, Temazepam) undergo Phase II glucuronidation only - prefer these benzodiazepines in liver disease.
CYP2D6 has the most clinically significant genetic polymorphism in psychiatry - PM, IM, EM, and UM phenotypes affect dosing of many psychotropic drugs.
Lower Kd means higher receptor affinity - Kd is the drug concentration needed to occupy 50% of receptors at equilibrium.
Minimum therapeutic clozapine level is 0.35 mg/L - aim for 0.35-0.60 mg/L trough, with levels above 1.0 mg/L carrying increased toxicity risk.
Inverse agonists reduce constitutive receptor activity below baseline - distinct from antagonists which only block agonist-induced activation.
Ciprofloxacin potently inhibits CYP1A2 - it can cause dangerous clozapine toxicity requiring dose reduction and level monitoring.
Benzodiazepine tolerance is primarily pharmacodynamic through GABA-A receptor adaptations - tolerance develops differentially to sedation (rapid) versus anxiolysis (slow/incomplete).
Bioavailability is the fraction of unchanged drug reaching systemic circulation - IV administration gives 100% bioavailability by definition.
CYP1A2 is induced by smoking (not nicotine) - smoking cessation can cause dangerous clozapine level rises requiring 30-50% dose reduction.
High lipophilicity is essential for crossing the blood-brain barrier - most psychotropic drugs are lipophilic to enable CNS penetration.
Valproate doubles lamotrigine levels by inhibiting glucuronidation - halve the lamotrigine dose and titrate very slowly when co-prescribed.
Tyramine is normally metabolised by gut wall MAO - irreversible MAOIs prevent this, allowing tyramine to cause noradrenaline release and hypertensive crisis.
Amisulpride and sulpiride are predominantly renally excreted - dose reduction is needed in renal impairment, and CYP450 interactions are minimal.
Pharmacodynamic interactions occur at the effect level (additive sedation, QTc prolongation) - pharmacokinetic interactions alter drug levels through ADME changes.
SSRIs/SNRIs deplete platelet serotonin, impairing aggregation - this pharmacodynamic interaction potentiates warfarin and increases bleeding risk.
Lithium is absorbed in the upper small intestine like sodium - peak levels at 1-2 hours (immediate-release) and brands are not interchangeable.
Extended-release formulations modify the absorption rate, not the elimination half-life - they provide sustained drug delivery enabling once-daily dosing.
Venlafaxine adds noradrenaline reuptake inhibition to serotonin reuptake inhibition - monitor blood pressure at higher doses and taper carefully on discontinuation.
Albumin binds acidic drugs (valproate, diazepam); alpha-1 acid glycoprotein binds basic drugs - hypoalbuminaemia increases free drug fractions.
Fluoxetine requires a five-week washout before starting an MAOI due to norfluoxetine's long half-life - other SSRIs require only two weeks.
Large Vd means extensive tissue distribution - haemodialysis is ineffective for overdose with high-Vd drugs like diazepam.
TCA cardiotoxicity is primarily caused by cardiac sodium channel blockade leading to QRS prolongation - treat with IV sodium bicarbonate.
NSAIDs reduce prostaglandin-mediated renal blood flow, decreasing lithium clearance - use paracetamol instead and monitor lithium levels if NSAIDs are unavoidable.
Tachyphylaxis to indirect sympathomimetics occurs through depletion of presynaptic noradrenaline stores - this is rapid and distinct from slower receptor-level tolerance.
Clomipramine is the most serotonin-selective TCA - its potent SERT inhibition explains its unique efficacy in OCD, though SSRIs are preferred first-line.
Prolonged-release melatonin (Circadin) is licensed for primary insomnia in adults aged 55+ - it acts on MT1/MT2 receptors in the suprachiasmatic nucleus.
Aged cheeses contain the highest tyramine levels and pose the greatest MAOI hypertensive crisis risk - dietary restrictions must continue for 2 weeks after stopping treatment.
Agomelatine combines MT1/MT2 agonism with 5-HT2C antagonism - it resynchronises circadian rhythms but requires regular liver function monitoring.
Buspirone is a 5-HT1A partial agonist with delayed onset (2-4 weeks) - no sedation, dependence, or withdrawal, but patients must be counselled about the delayed effect.
Moclobemide's reversible MAO-A binding can be displaced by tyramine - this competitive displacement reduces but does not eliminate tyramine reaction risk.
Mirtazapine causes the most weight gain among common antidepressants via H1 and 5-HT2C antagonism - monitor weight and consider weight-neutral alternatives if problematic.
Acetylcholinesterase inhibitors prolong suxamethonium action by inhibiting its breakdown - inform anaesthetists before surgery in patients taking these drugs.
Benzodiazepines for anxiety should be limited to 2-4 weeks maximum per BNF guidance - dependence develops quickly and millions of patients remain on long-term prescriptions.
Grapefruit juice irreversibly inhibits intestinal CYP3A4 via furanocoumarins - it increases oral bioavailability of CYP3A4 substrates for up to 72 hours.
Thiamine is essential for pyruvate dehydrogenase and Krebs cycle function - deficiency impairs aerobic brain energy production, selectively damaging mammillary bodies and thalamus.
Haloperidol plus IV methadone carries high TdP risk - always check ECG and electrolytes when combining QTc-prolonging drugs.
P-glycoprotein effluxes drugs from brain endothelium back into blood - it limits CNS drug access and is induced by St John's Wort and carbamazepine.
D2 receptors couple to Gi/o, inhibiting adenylyl cyclase and reducing cAMP - this contrasts with D1 receptors which couple to Gs and stimulate adenylyl cyclase.
Behavioural Science
80 high-yield facts
Sensitivity is the true positive rate - SnNOut means a sensitive test with a negative result rules out disease; it is unaffected by prevalence.
Maslow's hierarchy prioritises physiological and safety needs before psychological needs - this supports housing-first approaches in mental health care.
Pluralistic ignorance inhibits the interpretation stage of helping - bystanders misread each other's inaction as evidence the situation is not an emergency.
External validity concerns generalisability beyond the study sample - there is tension with internal validity; pragmatic trials prioritise external validity through broader criteria and real-world conditions.
The independent t-test compares means between two unrelated groups with normally distributed data - assumptions include independence, normality, and homogeneity of variance.
PICO structures clinical questions as Patient, Intervention, Comparison, Outcome - it facilitates efficient literature searching and is the foundation of evidence-based clinical question formulation.
The IAT measures automatic associations through reaction time differences - it reveals implicit biases that coexist with explicitly egalitarian attitudes in healthcare professionals.
Sherif's Robbers Cave demonstrated realistic conflict theory - competition breeds hostility, while superordinate goals requiring cooperation reduce prejudice between groups.
Group polarisation shifts opinions toward extremes of pre-existing inclinations - explained by persuasive arguments (novel supporting arguments) and social comparison (desire to exceed the group norm).
Cognitive dissonance produces attitude change when external justification is insufficient - the $1 group changed attitudes more than the $20 group because they lacked external justification for their lie.
The self-serving bias internalises success and externalises failure to protect self-esteem - its reversal in depression is a therapeutic target in CBT.
Human Development
80 high-yield facts
The parenthood transition involves identity reorganisation with both gains and challenges - marital satisfaction typically decreases but this varies; screen perinatally per NICE CG192.
Peer susceptibility peaks in mid-adolescence due to enhanced reward sensitivity to social acceptance with immature self-regulation - peer influence can be positive or negative depending on peer group norms; secure parenting buffers against negative peer pressure.
Preoperational children cannot fully grasp death's irreversibility and universality - use honest, age-appropriate language per Child Bereavement UK guidance; interpret grief responses within the child's developmental stage.
Winnicott's transitional objects occupy the space between internal and external reality - they represent the mother's comforting presence, are the infant's first creative possession, and are precursors to symbolisation.
Charmaz described loss of self in chronic illness through restricted life, social isolation, being discredited, and burdening others - therapeutic approaches should help reconstruct positive identity incorporating the illness.
The pincer grip is a fine motor milestone developing at 9-12 months - developmental assessment should cover gross motor, fine motor, language, social-emotional, and cognitive domains.
Avoidant attachment (Type A) shows suppressed distress and caregiver avoidance on reunion - it develops from consistently rejecting caregiving and manifests as dismissing adult attachment.
The preoperational stage (2-7 years) shows conservation failure due to centration and irreversibility - conservation develops in the concrete operational stage; number conservation typically appears first.
Hypothetico-deductive reasoning in the formal operational stage (11+ years) involves systematic hypothesis testing - not all adults achieve consistent formal operations; adolescent egocentrism is a characteristic feature.
Basic Neurosciences
80 high-yield facts
CRH from the hypothalamic PVN initiates the HPA axis cascade - CRH excess and HPA axis hyperactivity are among the most consistent biological findings in major depression.
The spinothalamic tract carries contralateral pain and temperature to VPL thalamus - it decussates at the spinal level via the anterior white commissure, unlike the dorsal columns which decussate in the medulla.
Prion diseases involve PrPC→PrPSc conversion propagating without nucleic acid - variant CJD typically presents with psychiatric symptoms first, making psychiatric awareness essential.
BDNF signals through TrkB receptor kinase to activate MAPK and PI3K-Akt survival pathways - reduced BDNF-TrkB signalling in depression is reversed by chronic antidepressant treatment.
Tabes dorsalis from tertiary syphilis causes selective posterior column degeneration - Argyll Robertson pupils, lightning pains, sensory ataxia, and Charcot joints are classic features.
The dentate nucleus is the largest deep cerebellar nucleus, projecting to the thalamus and motor cortex - the four nuclei from lateral to medial are dentate, emboliform, globose, and fastigial (Don't Eat Greasy Food).
PIB was the first amyloid PET tracer - it showed amyloid deposits 15-20 years before dementia onset. 18F-labelled tracers (florbetapir, flutemetamol) are now clinically available for amyloid imaging.
Neurofibrillary tangles contain hyperphosphorylated tau - Braak staging of tau pathology correlates with clinical severity better than amyloid burden.
NET is the primary mechanism for noradrenaline clearance - in the prefrontal cortex, NET also clears dopamine due to low DAT expression, giving NET inhibitors dual monoamine effects in this region.
Synaptic scaling is homeostatic plasticity that adjusts all synaptic strengths multiplicatively to maintain stable firing rates - it complements Hebbian plasticity and prevents network destabilisation.
Classification and Assessment
80 high-yield facts
The Stroop test measures response inhibition and cognitive interference control - the 'Stroop effect' reflects difficulty naming ink colours when they conflict with written colour words.
Flight of ideas = rapid topic shifts with traceable connections + pressure of speech (mania); derailment = topic shifts without discernible connections (schizophrenia). The connections are the key distinguishing feature.
ICD-11 gaming disorder requires impaired control, increasing priority, and continuation despite harm for ≥12 months - it affects a small minority of gamers and should only be diagnosed when significant functional impairment is present.
Derailment shifts between loosely connected topics without reaching a goal - distinguish from circumstantiality (reaches goal eventually), tangentiality (never returns to topic), and flight of ideas (rapid associations, typically manic).
Overvalued ideas sit between normal beliefs and delusions - they are comprehensible, held with excessive conviction and emotional investment, not fully fixed, but dominating functioning disproportionately.
Lorazepam challenge is first-line for catatonia (diagnostic and therapeutic) - ECT for refractory cases, and antipsychotics should be used cautiously as they can worsen catatonia or precipitate NMS.
ACE-III tests 5 domains (attention, memory, fluency, language, visuospatial) out of 100 - the VLOM ratio helps distinguish Alzheimer's from frontotemporal dementia.
Delusional perception involves a normal perception + incomprehensible delusional meaning in two stages - the key distinction is the un-understandable leap from perception to significance.
FND is diagnosed by positive signs of internal inconsistency (Hoover's sign, distractibility, give-way weakness) - it is not a diagnosis of exclusion, and modern misdiagnosis rates are approximately 5%.
ICD-11 removed schizophrenia subtypes due to poor reliability and validity - they are replaced by six symptom domain qualifiers (positive, negative, depressive, manic, psychomotor, cognitive) applicable across psychotic disorders.
The Dahlgren-Whitehead rainbow model shows concentric layers of health determinants - from individual factors through community networks to broader socioeconomic and environmental conditions.
Black African and Caribbean populations show three to five times higher psychosis rates in the UK - multiple social, environmental, and systemic factors contribute, not primarily genetics.
Cultural idioms of distress are culturally shaped patterns of experiencing and expressing suffering - the DSM-5 Cultural Formulation Interview provides a systematic assessment framework.
Goffman defined stigma as a discrediting attribute producing spoiled identity - he distinguished discredited from discreditable individuals and described strategies including passing and covering.
Self-stigma involves internalising societal prejudice, producing the 'why try' effect that undermines recovery goals - it is a critical barrier to treatment engagement and rehabilitation.
Structural stigma is embedded in institutional policies and laws - the Mental Health Act itself exemplifies differential treatment that systematically disadvantages people with mental illness.
Loss of social networks and discrimination are the most consistent mental health risk factors for immigrants - the healthy migrant effect provides initial protection that diminishes with post-migration adversity.
Neighbourhood social fragmentation is most consistently linked to psychosis risk - mechanisms include chronic stress, reduced social support, social defeat, and the ethnic density effect.
Women show higher rates of depression and anxiety while men show higher rates of substance use and suicide completion - biological, psychological, and social factors interact to produce these gender-specific patterns.
Incidence measures new cases per population-time at risk - it is essential for aetiological research because it captures the transition from health to disease.
False positives = (1 − specificity) × number without disease - in low-prevalence populations, even specific tests produce many false positives, dramatically reducing positive predictive value.
NNT = 1/absolute risk difference - it represents how many patients need treatment for one additional benefit; lower NNT indicates greater clinical effectiveness.
Confounding occurs when a third variable is associated with both exposure and outcome, distorting their apparent relationship - it can be controlled through randomisation, matching, stratification, or regression adjustment.
Recall bias occurs when disease status systematically influences the recall or reporting of past exposures - it is a major limitation of case-control studies and can be minimised by using objective measures and standardised interviews.
Meta-analysis statistically pools results from multiple studies using weighted averaging - it increases power and precision but requires assessment of heterogeneity and publication bias.
The evidence hierarchy runs from systematic reviews of RCTs (strongest) through individual RCTs, cohort, case-control, and case series to expert opinion (weakest) - GRADE provides a more nuanced quality assessment.
Qualitative research seeks subjective meaning using interpretivist methods, while quantitative research measures numerical relationships using positivist methods - quality is assessed through trustworthiness criteria rather than validity and reliability.
The normal distribution follows the 68-95-99.7 rule - 68% within ±1 SD, 95% within ±1.96 SD, and 99.7% within ±3 SD of the mean.
A p-value is the probability of the observed data (or more extreme) under the null hypothesis - it is NOT the probability the null is true; always consider effect sizes and clinical significance alongside p-values.
Intention-to-treat analysis includes all randomised participants in their original groups - it preserves randomisation benefits and provides pragmatic effectiveness estimates; per-protocol analysis may complement as a sensitivity analysis.
Blinding terminology is inconsistent - CONSORT recommends explicitly stating who was blinded; blinding participants prevents expectation bias, blinding assessors prevents detection bias, and blinding clinicians prevents performance bias.
An OR of 5.2 with CI not crossing 1.0 indicates a significant association - in case-control studies, the OR reflects odds of exposure in cases versus controls, not causation.
The Mann-Whitney U test is appropriate for ordinal data between two groups - it preserves rank ordering information that chi-squared ignores and makes no distributional assumptions.
Relative risk reduction can exaggerate perceived benefit - always consider absolute risk reduction and NNT alongside relative measures for meaningful clinical interpretation.
Thematic analysis identifies patterns of meaning through coding and theme development - Braun and Clarke's six-phase method is theoretically flexible and widely used in psychiatric research.
Specificity = true negatives / all without disease = 90% - SpPIn means a specific test with a positive result rules in diagnosis; the false positive rate is 1 − specificity.
Cohen's d of 0.3 is a small effect - benchmarks are 0.2 (small), 0.5 (medium), 0.8 (large); effect sizes quantify magnitude independently of sample size and complement p-values.
Test-retest reliability measures temporal stability by correlating scores from two administrations - the interval must balance memory effects and genuine change; ICC is preferred over Pearson's r for assessing agreement.
LR+ = sensitivity / (1 − specificity) - a LR+ of 4.5 means a positive result is 4.5 times more likely in those with disease; likelihood ratios are prevalence-independent and clinically applicable.
Research with NHS patients requires REC approval via IRAS, HRA approval, and local R&D confirmation - the Declaration of Helsinki underpins ethical research conduct.
NNH = 1/ARI where ARI is the absolute difference in adverse event rates between treatment and control groups - always round up to the next whole number.
Mann-Whitney U is for two independent groups with non-normal data - Wilcoxon signed-rank for paired non-normal data, and Kruskal-Wallis for three or more independent groups.
Contemplation means the patient recognises the problem but is ambivalent - motivational interviewing is the key therapeutic approach at this stage.
Large studies can produce statistically significant results for clinically meaningless effects - always examine Cohen's d (small=0.2, medium=0.5, large=0.8) alongside p-values.
Multiple comparisons inflate false positive rates - Bonferroni divides α by the number of tests, and the primary outcome should be pre-specified to avoid this problem.
Rogers' three core conditions are congruence, unconditional positive regard, and empathy - these are considered necessary and sufficient for therapeutic change in person-centred therapy.
Cognitive dissonance reduction involves rationalising conflicting beliefs and behaviours - people may change their beliefs rather than their behaviour to reduce psychological discomfort.
Downward social comparison enhances self-esteem by comparing to someone worse off - upward comparison can motivate or demoralise depending on perceived attainability.
The Rosenthal/Pygmalion effect shows that expectations become self-fulfilling prophecies - controlled in research through blinding, and relevant clinically as therapeutic optimism.
The Hawthorne effect is behaviour change due to being observed - it threatens internal validity and explains why audit results may not reflect routine practice.
IPA explores how individuals make sense of significant experiences - it uses small purposive samples, involves a double hermeneutic, and prioritises idiographic depth.
Dahlgren and Whitehead's rainbow model organises health determinants in concentric layers from individual to macro-environmental - the Marmot Review prioritised action on social determinants to reduce health inequalities.
The Theory of Planned Behaviour predicts behaviour through attitude, subjective norms, and perceived behavioural control - perceived behavioural control reflects self-efficacy and can directly influence behaviour.
Medicalisation redefines normal human experiences as medical problems - Illich described clinical, social, and cultural iatrogenesis, and Conrad analysed the drivers including pharmaceutical industry influence.
Mixed methods research combines quantitative and qualitative approaches for complementary understanding - common designs include convergent parallel, sequential explanatory, and sequential exploratory.
Propensity score matching reduces confounding by indication in observational studies - it balances measured confounders but cannot account for unmeasured confounding, unlike true randomisation.
Volunteer bias inflates treatment effects in research - the efficacy-effectiveness gap explains why RCT results may not replicate in routine practice, and pragmatic trials help bridge this gap.
Recall bias affects case-control studies because cases recall exposures differently from controls - prospective cohort designs avoid this by collecting exposure data before outcomes occur.
Narrative-based medicine complements evidence-based medicine by attending to individual patient stories - Greenhalgh and Charon developed the concept of narrative competence in clinical practice.
Benefit-risk assessment requires comparing NNT and NNH alongside the severity, reversibility, and clinical importance of each outcome - the LHH ratio (NNH/NNT) integrates benefit and harm into a single metric.
Jaspers distinguished Verstehen (empathic understanding of meaningful connections) from Erklären (causal explanation of non-meaningful processes) - this remains foundational for phenomenological psychopathology.
MI resolves ambivalence through collaboration, evocation, and autonomy support - using OARS techniques and eliciting change talk rather than directing.
65% delivered maximum shocks in Milgram's study - far exceeding expert predictions, demonstrating the powerful and underestimated influence of situational authority on behaviour.
Robins and Guze's five validators are clinical description, laboratory studies, delimitation, follow-up, and family studies - this framework underpins modern diagnostic validity in psychiatry.
The Marmot Review (2010) demonstrated the social gradient in health and proposed proportionate universalism - universal policies scaled to disadvantage across six policy domains.
PTSD is the most elevated condition in refugees at 20-40% prevalence - post-migration stressors including asylum uncertainty have independent effects on mental health beyond pre-migration trauma.
NPV is the probability of truly not having the condition given a negative result - it increases with lower prevalence and is critical for evaluating risk assessment tools in psychiatry.
Case-control studies are efficient for rare diseases, starting with cases and looking back at exposures - they calculate odds ratios rather than relative risk and are susceptible to recall bias.
Chi-squared tests association between two categorical variables using observed versus expected frequencies - Fisher's exact test is used when expected cell counts are below 5.
A 95% CI means 95% of similarly constructed intervals would contain the true parameter - it conveys both effect magnitude and estimation precision; CIs not crossing zero indicate statistical significance.
A significant chi-squared with multiple groups requires post-hoc pairwise comparisons with multiple testing correction - the overall test indicates an association exists but not where it lies.
Social identity theory shows that mere categorisation into groups triggers in-group favouritism - Tajfel's minimal group paradigm demonstrated bias without competition, conflict, or meaningful group differences.
ITT includes all randomised participants in their original groups regardless of compliance - per-protocol analysis is biased by differential dropout and should be secondary, not primary.
Safety-seeking behaviours (checking, reassurance, Googling) maintain health anxiety by preventing disconfirmation of catastrophic beliefs - CBT targets these maintaining factors.
Multiple regression predicts a continuous outcome from several predictors simultaneously - each coefficient shows the independent effect controlling for other variables; R² indicates total variance explained.
Problem-focused coping addresses the stressor directly - emotion-focused coping manages the emotional response. Both are adaptive depending on the controllability of the stressor.
The tripartite model separates stereotypes (cognitive), prejudice (affective), and discrimination (behavioural) - each component requires different intervention strategies in anti-stigma work.
Self-fulfilling prophecies occur when expectations shape behaviour that confirms those expectations - Rosenthal's Pygmalion study showed teacher expectations alone produced real IQ differences.
At 2 years, expect 50+ words and two-word combinations - only 5 words and no pointing suggests significant language delay; absent pointing warrants autism screening.
Independent sitting develops around 6 months following cephalocaudal progression - red flags include no sitting by 9 months and no walking by 18 months.
Thomas and Chess identified easy (40%), difficult (10%), and slow-to-warm-up (15%) temperament types - goodness of fit between temperament and environment determines developmental outcomes.
Symbolic pretend play involves representing imagined scenarios using objects and language - it develops from 2-6 years and requires mental representation; its absence or rigidity is significant in autism assessment.
First words appear around 12 months - receptive language precedes expressive; red flags include no words by 18 months and no phrases by 24 months; language regression warrants urgent assessment.
The ERA study supports a sensitive period for attachment with 6 months as a key threshold - early adoption leads to better outcomes, but later adoption still produces significant recovery, arguing against strict critical periods.
Winnicott's good enough mother provides adequate initial responsiveness that gradually introduces manageable frustration - this promotes autonomy and frustration tolerance; perfection is neither achievable nor desirable.
At 6 months expect rolling, transferring objects, canonical babbling, and early stranger awareness - red flags include absent social smile, no reaching, and no vocalisation.
Postnatal depression primarily risks emotional regulation and attachment security through impaired interactive sensitivity - Tronick's still-face paradigm demonstrates infant vulnerability to disrupted contingent responsiveness.
Wood, Bruner, and Ross coined 'scaffolding' for graduated tutorial support within the ZPD - effective scaffolding requires contingent responsiveness, adjusting support based on the learner's moment-to-moment performance.
The dual-systems model explains adolescent risk-taking through early limbic reward system maturation outpacing later prefrontal regulatory development - the prefrontal cortex does not fully mature until the mid-20s.
Adolescent self-harm vulnerability reflects immature emotional regulation with heightened emotional intensity - it serves emotion regulation, communication, and self-punishment functions; understanding individual function guides intervention.
Kübler-Ross's stages are denial, anger, bargaining, depression, acceptance - they are not linear or universal; the model has been criticised for lacking empirical support but remains influential in normalising grief responses.
Complicated grief features persistent yearning and functional impairment beyond 12 months - normal grief can include intense sadness, anger, dreams, and brief hallucinations; PGD is now a diagnostic entity in ICD-11 and DSM-5-TR.
Worden's four tasks are accepting reality, processing pain, adjusting to the world without the deceased, and finding enduring connection while reinvesting in life - tasks imply active mourning work rather than passive progression.
Post-bereavement hallucinatory experiences occur in 30-50% of bereaved people - they are normal, typically comforting, and self-limiting; distinguish from psychosis by context, recognition, and absence of other psychotic features.
Stroebe and Schut's dual process model involves oscillation between loss-oriented and restoration-oriented coping - both are necessary; inflexible dominance of either orientation indicates problematic grief.
Rowe and Kahn's successful ageing model requires low disease risk, high function, and active engagement - criticised for applying to few older adults and neglecting subjective wellbeing in those with disability.
Socioemotional selectivity theory explains selective investment in meaningful relationships as perceived time shortens - the positivity effect reflects active emotion regulation; the shift is driven by time perspective, not age alone.
Baltes' SOC model describes adaptive ageing through selection (prioritising goals), optimisation (maximising performance in chosen domains), and compensation (finding alternative means) - higher SOC use is associated with better wellbeing.
Gender constancy (understanding gender is permanent despite appearance changes) develops around 6-7 years - it parallels Piagetian conservation; Kohlberg, social learning, and gender schema theories offer complementary explanations.
Post-traumatic growth involves positive change through struggle - five domains include appreciation of life, relationships, personal strength, new possibilities, and spiritual change; PTG coexists with distress rather than replacing it.
Infertility produces grief for an imagined future and identity threat - NICE CG156 recommends counselling throughout fertility treatment; distinguish disenfranchised grief from clinical depression requiring specialist intervention.
Klass, Silverman, and Nickman established the continuing bonds perspective - maintaining transformed relationships with the deceased is normal and often adaptive; bonds characterised by positive integration are healthier than those driven by yearning and searching.
Multifinality means the same risk factor leads to different outcomes in different people - it complements equifinality (different pathways, same outcome); both principles support individualised formulation over deterministic causal models.
Most parents adjust well to the empty nest - many experience improved marital satisfaction and personal freedom; difficulty is predicted by exclusive parenting identity and marital dissatisfaction; the 'cluttered nest' may be more challenging.
Upward social comparison with idealised online content is the primary proposed mechanism - RCPCH guidance highlights passive scrolling as more harmful than active engagement; always assess cyberbullying and sleep disruption.
Only 10-26% experience a genuine midlife crisis - distinguish normative reflection from clinical depression requiring treatment per NICE CG90; pre-existing vulnerabilities interact with normative midlife challenges.
Gerotranscendence involves a positive developmental shift toward cosmic perspective, decreased self-centredness, and increased life satisfaction - it is distinct from disengagement, depression, and cognitive decline; primarily based on Scandinavian research.
Moffitt's LCP antisocial behaviour involves neurodevelopmental deficits interacting with adversity from childhood - AL behaviour reflects normative adolescent maturity gap and typically desists; LCP shows worse outcomes but is less common.
Epigenetic modifications alter gene expression without changing DNA sequence - DNA methylation and histone modification are the key mechanisms, and early adversity can programme stress responses through glucocorticoid receptor methylation.
Stern's four domains of self are emergent, core, subjective, and verbal - they are layered rather than sequential, and intersubjective relatedness emerges at 7-9 months through affect attunement.
Mentalisation is understanding behaviour in terms of mental states - it develops through secure attachment and marked mirroring, and its disruption is central to BPD as addressed by MBT.
Neuroplasticity is maximal in early childhood during the period of synaptic overproduction - the Kennard principle suggests earlier injury allows greater functional reorganisation.
Bronfenbrenner's five systems are micro, meso, exo, macro, and chrono - the model emphasises that development occurs through interactions across nested environmental layers.
Key language red flags are no babbling by 12 months, no words by 18 months, no two-word phrases by 24 months, and absence of pointing by 14 months - the naming explosion typically occurs around 18 months.
Gillick competence allows under-16s to consent to treatment if they have sufficient understanding - but a competent minor's refusal of treatment can be overridden by parents or the court.
Internal working models are mental templates of self and others constructed from early attachment experiences - they are relatively stable but modifiable, and explain the intergenerational transmission of attachment patterns.
Normal ageing impairs fluid intelligence (processing speed, working memory) while preserving crystallised intelligence (vocabulary, semantic knowledge) - MCI involves decline beyond age norms with preserved functional independence.
Prolonged grief disorder (ICD-11: >6 months; DSM-5-TR: >12 months) affects 7-10% of bereaved individuals - it is distinct from depression and normal grief, and complicated grief treatment is the evidence-based intervention.
The Oedipus complex occurs in the phallic stage (3-6 years) - resolution through identification with the same-sex parent forms the superego, and fixation at any psychosexual stage produces characteristic personality patterns.
School refusal is anxiety-based non-attendance with somatic symptoms and parental knowledge - distinguished from truancy by emotional distress, staying at home, and absence of antisocial behaviour.
Gender identity assessment in adolescence requires comprehensive developmental formulation - the Cass Review emphasised holistic assessment, staged intervention, and the need for further evidence on hormonal treatments.
Young carers have a legal right to assessment under the Children and Families Act 2014 - clinicians should recognise the caring role, facilitate support, and balance developmental protection with acknowledging positive aspects of caregiving.
Regression after sibling birth affects approximately 50% of firstborns and is typically transient - Dunn and Kendrick's research shows it resolves with maintained parental attention, and sibling relationships provide important developmental learning opportunities.
Social media harms are dose-dependent and pattern-specific - passive consumption and social comparison are most harmful, girls are more vulnerable, and spending over three hours daily doubles depression risk in adolescents.
Cumulative disadvantage produces widening disparities through cascading effects across developmental transitions - Dannefer showed within-cohort inequality increases with age, supporting sustained multi-level interventions rather than single-factor approaches.
Rowe and Kahn define successful ageing as low disease probability plus high functional capacity plus active engagement - criticised for excluding those with chronic conditions, with Baltes' SOC offering a more inclusive alternative.
Cognitive reserve enables tolerance of greater brain pathology before symptoms emerge - built through education, occupation, and social engagement, it involves active neural efficiency and compensation, not just larger brain volume.
Intergenerational trauma transmits primarily through disrupted parenting and attachment - Yehuda's research suggests epigenetic HPA axis programming, and therapeutic intervention targeting parental reflective function can break the cycle.
Ainsworth's sensitivity dimension involves perceiving, interpreting, and responding to infant signals - it is the strongest predictor of attachment security; video-feedback interventions can improve maternal sensitivity.
The ZPD is the gap between independent and assisted performance - scaffolding provides temporary, responsive support within this zone that is gradually withdrawn as competence develops.
Kohlberg's Stage 6 involves universal ethical principles transcending law - most adults reason at the conventional level, and the theory has been criticised for gender and cultural bias.
The ACE Study showed a graded dose-response between cumulative childhood adversity and adult disease - ACE scores ≥4 significantly increase risks of mental illness, chronic disease, and premature death.
Piaget's egocentrism is a cognitive limitation of the preoperational stage - children cannot represent others' perspectives; Hughes showed that simplified tasks reveal earlier perspective-taking abilities.
Assimilation incorporates new information into existing schemas; accommodation modifies schemas for new information - equilibration drives development through cycles of cognitive balance and imbalance.
Industry versus inferiority (6-12 years) develops competence through achievement - the school and peer group are the primary developmental contexts; pervasive inferiority is a risk factor for childhood depression.
Internal working models form during the clear-cut attachment phase (6-8+ months) as complementary representations of self and other - they guide relationship expectations throughout life but can be modified through therapeutic relationships.
Early skin-to-skin contact promotes but is not essential for bonding - attachment develops through accumulated responsive interactions over months; parents separated from newborns can still develop excellent bonds.
Disengagement theory proposed inevitable mutual social withdrawal as adaptive - extensively criticised as it normalises ageist exclusion; socioemotional selectivity theory offers a more nuanced account of selective social investment.
Butler's life review facilitates coherent life narrative and meaning-making in later life - it supports Erikson's integrity resolution; structured life review therapy is evidence-based for late-life depression.
Secure attachment (Type B) shows confident exploration, moderate separation distress, and positive reunion - it is associated with sensitive caregiving and comprises approximately 65% of typical samples.
Depression is most strongly associated with unemployment - Jahoda's model identifies five latent functions of work beyond income; the relationship is bidirectional with the exposure effect generally stronger.
Fonagy developed mentalisation theory linking attachment, reflective function, and BPD - MBT enhances the capacity to understand behaviour in terms of mental states; mentalisation develops through secure attachment in early childhood.
The prefrontal cortex matures last (by ~25 years) - the mismatch between early limbic maturation and late prefrontal maturation explains adolescent risk-taking, impulsivity, and emotional reactivity.
Generativity versus stagnation is the crisis of middle adulthood - it involves contributing to future generations through parenting, mentoring, or creativity, and its resolution produces the virtue of care.
The Kauai study identified three domains of resilience: individual characteristics (temperament, intelligence), a supportive relationship with at least one competent adult, and external support systems - resilience is a process, not a fixed trait.
Circle of Security maps secure base (exploration) and safe haven (comfort) needs - 'shark music' describes parental defensive responses rooted in their own attachment history, and the intervention shifts attachment classification toward security.
Piaget's heteronomous morality features absolute rules, consequence-based judgement, and immanent justice - autonomous morality develops from about 10 years with intention-based reasoning and rule flexibility.
Crystallised intelligence (knowledge) is preserved while fluid intelligence (novel problem-solving) declines with ageing - this Cattell-Horn distinction is fundamental to understanding normal versus pathological cognitive change in older adults.
Bowlby's four grief phases are numbness, yearning/searching, disorganisation/despair, and reorganisation - they parallel the Robertson separation response and reflect the attachment system seeking the lost figure.
The dorsal raphe nucleus in the upper pons provides the major serotonergic innervation to the forebrain - SSRIs work by increasing serotonin at synapses from these projections, with a therapeutic delay due to autoreceptor desensitisation.
Ionotropic receptors are fast ligand-gated ion channels (milliseconds) - metabotropic receptors are slow G-protein coupled receptors (seconds to minutes).
Early LTP requires NMDA-mediated Ca2+ influx activating CaMKII - this phosphorylates and inserts AMPA receptors to strengthen the synapse without new protein synthesis.
COMT Val158Met - Val = high activity = low prefrontal dopamine = poorer working memory; Met = low activity = higher prefrontal dopamine = better cognition.
Caffeine blocks adenosine A1 and A2A receptors - adenosine accumulates during wakefulness promoting sleep, and caffeine prevents this. A2A-D2 receptor interactions link the adenosine and dopamine systems.
CAG expansion in HTT produces expanded polyglutamine causing huntingtin aggregation - psychiatric symptoms often precede chorea, and genetic anticipation occurs with paternal transmission.
Substantia nigra pars compacta dopaminergic neuron loss is the hallmark of Parkinson's - 60-80% loss occurs before motor symptoms appear, and Braak staging shows pathology begins in the medulla and olfactory system.
The fusiform face area in the inferior temporal cortex is specialised for face recognition - bilateral damage causes prosopagnosia with intact basic visual processing.
Déjerine-Roussy syndrome results from VPL thalamic infarction causing contralateral burning pain with allodynia - it responds poorly to conventional analgesics and requires neuropathic pain agents like amitriptyline or gabapentin.
Adult neurogenesis occurs in the hippocampal dentate gyrus and subventricular zone - antidepressants and lithium promote hippocampal neurogenesis, supporting the neurogenesis hypothesis of depression.
MAO-A deaminates serotonin and noradrenaline (target for antidepressants) - MAO-B deaminates phenylethylamine (target for Parkinson's treatment). Both deaminate dopamine and tyramine.
Clathrin-mediated endocytosis is the main vesicle retrieval mechanism - clathrin coats, dynamin pinches off, and the vesicle is recycled in ~15-30 seconds.
Childhood absence epilepsy shows generalised 3 Hz spike-and-wave on EEG generated by thalamocortical circuits - ethosuximide blocks T-type calcium channels and is first-line treatment.
Melatonin from the pineal gland is the key circadian biomarker - DLMO marks circadian phase, and melatonin synthesis is controlled by SCN via sympathetic innervation through the superior cervical ganglion.
Herpes simplex encephalitis preferentially affects the temporal lobes with PLEDs on EEG - it causes haemorrhagic necrosis of limbic structures and requires urgent aciclovir treatment.
Morning bright light therapy at 10,000 lux for 30 minutes is first-line for SAD - it works by advancing the delayed circadian phase through melanopsin-mediated SCN signalling and correcting phase misalignment.
The WCST assesses cognitive flexibility - perseverative errors indicate dorsolateral prefrontal dysfunction and inability to shift mental sets in response to changing contingencies.
NPSLE involves autoantibody-mediated neuronal damage and cerebral vasculitis - anti-ribosomal P antibodies associate with psychosis, and differentiating from steroid-induced symptoms is essential.
Hepatic encephalopathy is caused primarily by ammonia-induced astrocyte swelling - asterixis and sleep-wake reversal are characteristic, and benzodiazepines must be avoided.
Visual hallucinations in DLB result from cholinergic deficiency disrupting visual attention - cholinesterase inhibitors are first-line treatment, and conventional antipsychotics must be avoided.
Hypercalcaemia causes 'psychic moans' through neuronal membrane stabilisation and reduced neurotransmitter release - symptoms correlate with both calcium level and rate of rise.
SACD from B12 deficiency affects posterior and lateral columns - neurological damage can occur before anaemia, and folate supplementation without B12 dangerously masks the deficiency.
T4 is the nipple dermatome, T10 is the umbilicus - dermatomes overlap substantially so single root lesions produce limited sensory loss, and non-dermatomal patterns suggest functional rather than organic aetiology.
Broca's area in the inferior frontal gyrus produces non-fluent aphasia with preserved comprehension - it connects to Wernicke's area via the arcuate fasciculus.
The lateral geniculate nucleus is the thalamic relay for vision - it has six layers (2 magnocellular for motion, 4 parvocellular for colour/detail) and projects via the optic radiation to the primary visual cortex.
The anterior hypothalamus controls cooling (vasodilation, sweating), while the posterior hypothalamus controls heating (shivering, vasoconstriction) - neuroleptic malignant syndrome involves hypothalamic thermoregulatory failure from dopamine blockade.
Sleep-related hypermotor epilepsy produces stereotyped brief hyperkinetic nocturnal events from NREM sleep - distinguished from parasomnias by their stereotypy, brevity, and response to carbamazepine.
Normal EEG during a clinically significant event is the gold standard for diagnosing NEAD - video-EEG monitoring capturing a typical attack is the definitive investigation for distinguishing functional from epileptic seizures.
Craik and Lockhart's levels-of-processing framework shows deeper semantic encoding creates stronger memories - the self-reference effect represents particularly deep encoding with clinical rehabilitation applications.
The tonic phase shows generalised low-voltage fast activity evolving to high-amplitude spikes - the clonic phase shows progressively slowing spike-and-wave complexes, followed by post-ictal suppression.
Korsakoff syndrome produces diencephalic amnesia with confabulation from thiamine deficiency - mammillary body and mediodorsal thalamic damage disrupts the Papez circuit.
Tactile agnosia is failure to recognise objects by touch despite intact somatosensation - it reflects contralateral parietal association cortex damage with preserved primary sensory processing.
Uraemic encephalopathy results from neurotoxic solute accumulation in renal failure - guanidino compounds act at NMDA and GABA receptors, and symptoms partially improve with dialysis.
Methanol toxicity damages the optic nerve via formic acid inhibiting cytochrome oxidase - bilateral putaminal necrosis is the characteristic brain lesion, and fomepizole blocks toxic metabolism.
HSE causes necrotising temporal lobe inflammation from HSV-1 - it presents with psychiatric and neurological features, requires immediate aciclovir, and may cause permanent amnesia.
Sympathetic preganglionic neurons arise from T1-L2 intermediolateral column - they have short preganglionic (cholinergic) and long postganglionic (noradrenergic) fibres, except sweat glands and the adrenal medulla.
The neural crest migrates from the dorsal neural tube to form PNS, Schwann cells, melanocytes, adrenal medulla, and craniofacial structures - DiGeorge syndrome is a neurocristopathy with high schizophrenia risk.
Complete cord transection causes bilateral UMN paralysis, complete sensory loss, and autonomic dysfunction below the lesion - initial spinal shock with flaccidity evolves into spasticity over weeks.
Schwann cells and macrophages clear PNS myelin debris during Wallerian degeneration - this rapid clearance enables PNS regeneration, unlike the CNS where inhibitory myelin debris persists.
Gerstmann syndrome from dominant angular gyrus damage produces agraphia, acalculia, finger agnosia, and right-left disorientation - it is a key localising sign in neuropsychiatry.
The right inferior parietal lobule is dominant for spatial attention - its damage produces left-sided neglect because the left hemisphere cannot compensate for bilateral attentional processing.
The mu opioid receptor mediates analgesia, euphoria, respiratory depression, and dependence - it disinhibits VTA dopamine neurons to produce rewarding effects.
HVA is the final metabolite of dopamine (via MAO and COMT) - CSF HVA reflects central dopamine turnover. 5-HIAA reflects serotonin turnover, MHPG reflects noradrenaline turnover.
Alzheimer's shows bilateral temporoparietal and posterior cingulate hypometabolism on FDG-PET - FTD shows frontal hypometabolism, and DLB shows occipital hypometabolism. These patterns aid differential diagnosis.
Muscarinic receptor blockade by TCAs causes dry mouth, blurred vision, constipation, urinary retention, and delirium - elderly patients are particularly vulnerable, and cumulative anticholinergic burden increases dementia risk.
The superior sagittal sinus is the most commonly thrombosed sinus - CVT causes raised ICP, bilateral parasagittal haemorrhagic infarcts, seizures, and psychiatric symptoms, treated with anticoagulation.
Depression shows shortened REM latency, increased REM density, and reduced slow-wave sleep - reflecting cholinergic-aminergic imbalance; most antidepressants suppress REM; per NICE NG222, sleep disturbance is a core symptom of depression.
The tuberomammillary nucleus is the brain's sole histaminergic nucleus promoting wakefulness via H1 receptors - it is inhibited by VLPO during sleep and stabilised by orexin during wakefulness.
Stage N1 shows alpha dropout, theta activity, vertex sharp waves, and slow rolling eye movements - it is the lightest sleep stage with a low arousal threshold and constitutes only 5% of total sleep.
Aphasia during left carotid amobarbital injection confirms left hemisphere language dominance - the Wada test is essential for presurgical assessment of language lateralisation and contralateral memory capacity.
Semantic memory stores general world knowledge independent of personal context - it is supported by anterior temporal lobes and is selectively lost in semantic dementia.
The right ventrolateral prefrontal cortex monitors retrieval accuracy and source attribution - its damage causes source monitoring failures, false memories, and confabulation without impaired encoding.
Beta-endorphin from POMC acts at mu receptors producing analgesia and reward - enkephalins prefer delta receptors and dynorphins prefer kappa receptors, which produce dysphoria.
LTD is induced by modest NMDA receptor calcium entry activating phosphatases - it reverses LTP through AMPA receptor internalisation and is important for memory extinction and circuit refinement.
The nucleus accumbens in the ventral striatum is the brain's reward centre - all drugs of abuse increase dopamine release here, and the mesolimbic VTA-nucleus accumbens pathway is central to addiction and psychosis.
The medulla contains vital cardiovascular and respiratory centres - it also houses the pyramidal decussation, area postrema chemoreceptor trigger zone, and lower cranial nerve nuclei (IX-XII).
5-HT2A antagonism disinhibits dopamine in the prefrontal cortex - this may improve negative/cognitive symptoms and explains why atypical antipsychotics are preferred over typical antipsychotics.
SPECT detects single photons (lower resolution, cheaper, more available) while PET detects coincident photon pairs (higher resolution, needs cyclotron). DaTSCAN SPECT distinguishes DLB from Alzheimer's disease.
CACNA1C encodes the L-type calcium channel alpha-1C subunit - it is the top GWAS hit for bipolar disorder and connects to calcium-dependent signalling, neuronal excitability, and potential calcium channel blocker treatments.
Reduced glial density (astrocytes, oligodendrocytes) in sgACC is the most consistent post-mortem finding in depression - this supports glial dysfunction and neurotrophic hypotheses rather than simple neuronal loss.
Cortisol negative feedback operates at hippocampus, PVN, and pituitary - impaired feedback (GR resistance) causes cortisol elevation in depression, while enhanced feedback causes low cortisol in PTSD.
WMH in late-life depression represent ischaemic small vessel disease disrupting frontal-subcortical mood circuits - 'vascular depression' is associated with treatment resistance and executive dysfunction.
D2 receptors are Gi-coupled → inhibit adenylyl cyclase → ↓cAMP → ↓PKA; all licensed antipsychotics block D2; 65-80% occupancy for therapeutic effect, >80% risks EPS and hyperprolactinaemia (Kapur window). Maudsley Guidelines / NICE NG178.
UMN lesions produce spasticity, hyperreflexia, and extensor plantars - LMN lesions produce flaccidity, wasting, and fasciculations - the combination of UMN signs with psychiatric symptoms suggests organic pathology requiring urgent investigation.
The VLPO promotes sleep by releasing GABA and galanin to inhibit arousal centres - it forms a mutually inhibitory flip-flop switch with wake-promoting neurons, stabilised by orexin.
Neuroplasticity enables lifelong brain reorganisation at molecular, synaptic, and systems levels - it underpins learning, recovery from injury, and therapeutic change in psychotherapy and pharmacotherapy.
/know paradigm (Tulving, 1985) operationalises this distinction: 'remember' responses indicate recollection (accompanied by specific contextual details), while 'know' responses indicate familiarity (a sense of prior encounter without contextual detail).
The dorsal column pathway decussates in the lower medulla - gracilis (legs) and cuneatus (arms) nuclei give rise to internal arcuate fibres that cross to form the medial lemniscus ascending to VPL thalamus.
Watershed infarcts occur at arterial boundary zones where perfusion pressure is lowest - the ACA-MCA boundary causes the man-in-a-barrel syndrome, and global hypoperfusion is the typical mechanism.
Horner syndrome produces miosis, partial ptosis, and anhidrosis from sympathetic pathway disruption - Pancoast tumour damages the second-order neuron at the lung apex.
Section 2 is for assessment (28 days, 2 doctors, AMHP), Section 3 for treatment (6 months), Section 4 for emergencies (72 hours, 1 doctor) - Section 2 is used when the diagnosis is unclear and assessment is the primary need.
Circumstantiality = overinclusive detour that eventually reaches the goal - tangentiality = goal never reached, derailment = no direction at all, flight of ideas = rapid shifts with pressure of speech.
PANSS has 30 items scored 1-7 across positive (7), negative (7), and general (16) subscales - treatment response is conventionally ≥20% reduction in total score.
Echo phenomena reflect impaired inhibition of automatic imitation - they occur in catatonia, Tourette syndrome, ASD, frontotemporal dementia, and transcortical aphasias, not exclusively in any single condition.
The 4Ps framework organises formulation into predisposing, precipitating, perpetuating, and protective factors across biopsychosocial domains - it individualises understanding and guides targeted treatment planning.
Intellectualisation focuses on cognitive/abstract aspects while avoiding emotional engagement - it is a neurotic-level defence, distinguished from denial (non-recognition of reality) and suppression (conscious, mature postponement of emotion).
Neologisms are genuinely new words with private meanings - distinguished from paraphasias (word substitutions in aphasia), metonymy (approximate word use), and clanging (sound-based associations).
ICD-11 now distinguishes bipolar I (full mania) from bipolar II (hypomania + depression) - mixed features can qualify any mood episode, and rapid cycling is formally recognised as a pattern specifier.
HoNOS is a 12-item clinician-rated measure mandated for NHS mental health services - it covers behaviour, impairment, symptoms, and social domains scored 0-4 per item.
Couvade syndrome involves pregnancy-like symptoms in the partner of a pregnant woman - it is common, benign, and resolves after delivery. It is not a formal psychiatric diagnosis.
PCL-R scores 0-40 with psychopathy cut-off ≥30 - it has a two-factor structure (interpersonal/affective and lifestyle/antisocial) and is the strongest single predictor of violent recidivism.
MADRS has 10 items scored 0-6 (max 60) with remission ≤10 - it was designed for sensitivity to change with fewer somatic items than the HAM-D, making it preferred for antidepressant trials.
Thought echo (Gedankenlautwerden) is hearing one's own thoughts aloud - distinguished from thought broadcasting by being a personal auditory experience rather than a belief about transmission.
Primary delusions are psychologically irreducible and un-understandable - secondary delusions arise understandably from mood, hallucinations, or other psychopathology.
Autochthonous delusions arise suddenly and fully formed without antecedent - the purest form of primary delusion in Jaspers' framework, representing complete psychological irreducibility.
Delusional atmosphere describes the uncanny transformation of the perceived world before delusion formation - everything seems changed and meaningful but the patient cannot articulate why.
Persistent delusional disorder requires delusions for 3+ months without hallucinations, negative symptoms, or disorganisation - personality is preserved and delusions are typically non-bizarre.
Schizoaffective disorder requires concurrent full criteria for both schizophrenia and a mood episode - psychotic symptoms outside mood episodes distinguish it from psychotic depression.
DPDR requires persistent depersonalisation/derealisation with intact reality testing - transient episodes are common and normative; the disorder is diagnosed only when persistent and functionally impairing.
The Cultural Formulation Interview (CFI) is a DSM-5 structured framework exploring cultural context of clinical presentations - essential for distinguishing culturally normative beliefs from psychopathology in diverse populations.
The 4P structural formulation uses predisposing, precipitating, perpetuating, and protective factors across biopsychosocial domains - it provides individualised understanding beyond categorical diagnosis.
Safety planning uses a hierarchical six-step structure - warning signs, internal coping, social distraction, family/friend support, professional contacts, and means restriction. It replaces no-suicide contracts.
The Boston Naming Test uses 60 graded line drawings to assess confrontation naming - error type analysis (semantic vs phonemic) and response to cueing help localise the language deficit.
WAIS-IV yields FSIQ plus four indices (VCI, PRI, WMI, PSI) - profile analysis reveals patterns of cognitive strengths and weaknesses useful for differential diagnosis.
CORE-OM is a 34-item measure covering well-being, symptoms, functioning, and risk - freely available, widely used in NHS psychological therapies, and sensitive to therapeutic change.
The CAN assesses 22 domains rating no need, met need, or unmet need from patient and staff perspectives - unmet needs identify gaps in care and are associated with poorer outcomes.
Section 3 authorises treatment detention for up to 6 months (renewable), requires two medical recommendations and AMHP application, with Nearest Relative consultation - it differs from Section 2 (assessment, 28 days, non-renewable).
OCRDs share repetitive thoughts/behaviours, CSTC circuit involvement, and genetic overlap - ICD-11 separated them from anxiety disorders based on distinct phenomenology, neurobiology, and treatment response.
Olfactory reference disorder is a new ICD-11 OCRD diagnosis - persistent preoccupation with emitting a foul odour not perceived by others, with repetitive behaviours and avoidance. Insight ranges from good to absent.
Crow's Type I = positive symptoms, dopamine dysfunction, good antipsychotic response. Type II = negative symptoms, structural brain changes, poor response. The dichotomy is historically important but oversimplified.
ICD-11 unified all autism subtypes into a single ASD diagnosis with specifiers - Asperger syndrome is no longer a separate diagnosis. Rett syndrome was moved to neurological conditions.
4AT scores alertness, attention, AMT4, and acute change (≥4 suggests delirium). CAM requires acute onset + inattention + disorganised thinking or altered consciousness. Both are validated bedside delirium tools.
The BPRS has 18 items rated 1-7 (total 18-126), is quicker than PANSS, and clusters into thinking disturbance, withdrawal, hostility, and anxious-depression factors.
SAS has 10 items for drug-induced parkinsonism (mean score >0.3 = significant), AIMS is for tardive dyskinesia, and Barnes is for akathisia - these three scales together cover the main extrapyramidal syndromes.
The MSM stages TRD across duration, severity, and treatment failures (3-15 points) - it is more comprehensive than the unidimensional Thase-Rush model and guides escalation to ECT or novel treatments.
ATPD requires onset within 2 weeks (usually 48 hours) and typically remits within 1-3 months - ICD-11 simplified the ICD-10 subtypes into a single category.
The Mini-ICF-APP has 13 items assessing activity and participation domains based on the ICF framework - it provides domain-specific functional assessment for work capacity and disability evaluation in mental disorders.
Luria's approach is qualitative and hypothesis-driven, examining process rather than product - based on three functional units (arousal, sensory processing, executive regulation) and aiming to identify which component of a functional system is disrupted.
BFRBDs (excoriation and trichotillomania) are classified under OCRDs in ICD-11 - characterised by repetitive body-directed behaviours causing physical damage, distinct from OCD by absence of obsessional thoughts.
AUDIT scores guide response - 8-15 hazardous (brief advice), 16-19 harmful (brief counselling), ≥20 possible dependence (specialist referral). AUDIT-C (first 3 items) is a valid brief screen.
BDI-II is a 21-item self-report scale (0-63) with cut-offs: minimal <14, mild 14-19, moderate 20-28, severe ≥29 - distinguish from clinician-rated scales (HAM-D, MADRS) and brief screening tools (PHQ-9).
ICD-11 neurodevelopmental disorders share developmental onset, frequent co-occurrence, and neurodevelopmental aetiology - critically, they are recognised as lifespan conditions, not exclusively childhood disorders.
Complex PTSD = PTSD core symptoms PLUS disturbances in self-organisation (affect dysregulation, negative self-concept, relationship difficulties) - it follows prolonged interpersonal trauma and is new to ICD-11.
The MMSE has poor sensitivity for MCI and lacks executive function testing - the MoCA is more sensitive for mild cognitive impairment (90% vs 18%) and includes executive function assessment.
Thought withdrawal requires attribution to an external agency removing thoughts - without this attribution, the phenomenon is thought blocking, not thought withdrawal.
Depersonalisation = detachment from self; derealisation = detachment from the world - both have preserved reality testing, distinguishing them from delusions and psychotic phenomena.
MCA's five principles are presumption of capacity, supported decision-making, unwise decisions allowed, best interests, and least restrictive option - capacity is assessed using the two-stage functional test.
HAM-D 17-item is clinician-rated with a strong somatic emphasis - response = ≥50% reduction, remission = score ≤7, and the MADRS offers a 10-item alternative with less somatic weighting.
Nihilistic delusions range from bodily nihilism to cosmic nihilism - they are most characteristic of severe psychotic depression in the elderly and represent the extreme endpoint of Beck's negative cognitive triad.
The clock drawing test assesses visuospatial, semantic, and executive function - the pull-to-stimulus error (placing minute hand at 10 instead of 2 for 'ten past') reflects executive dysfunction.
SAPAS is an 8-item personality disorder screen with sensitivity 0.94 at a cut-off of ≥3 - it takes 2-3 minutes and identifies patients requiring comprehensive assessment with IPDE or SCID-5-PD.
ICD-11 dissociative disorders include DID as a formal diagnosis, separates trance from possession trance, and replaces conversion disorder with dissociative neurological symptom disorder.
Made experiences (actions, feelings, impulses) all share loss of agency with external attribution - distinct from dissociation, depersonalisation, and compulsions.
Diagnostic overshadowing attributes mental illness symptoms to the learning disability - it is a major cause of psychiatric under-diagnosis in people with intellectual disabilities.
ICD-11 recognises ADHD across the lifespan with developmental onset - adults can be diagnosed retrospectively. Hyperactivity in adults often presents as inner restlessness rather than overt motor activity.
The Rey Complex Figure assesses visuospatial construction, organisational strategy, and visual memory - copy strategy reveals executive function while recall reveals non-verbal memory integrity.
Schneider's second-rank symptoms include perplexity, emotional blunting, mood changes, and non-specific hallucinations - they are less diagnostically specific than first-rank symptoms and occur across multiple psychiatric conditions.
Folie à deux involves transfer of delusions from a dominant to a submissive partner in social isolation - separation typically resolves the induced partner's delusions, which distinguishes it from independent psychosis.
GAD-7 severity ranges: 0-4 minimal, 5-9 mild, 10-14 moderate, 15-21 severe - screening cut-off is ≥10, and the GAD-2 (first 2 items, ≥3) is a valid ultra-brief screen.
CGI has two single-item ratings - CGI-Severity (1-7 illness severity) and CGI-Improvement (1-7 change from baseline). Response = CGI-I ≤2 (very much or much improved).
Somatic passivity requires attribution of bodily sensations to external control - distinguish from somatic hallucinations (false perception) and cenesthopathy (unusual sensation without external attribution).
Manic grandiosity is mood-congruent and fluctuates with mood - schizophrenic grandiosity is mood-incongruent, persistent, and embedded within broader psychotic phenomena.
Capacity assessment is decision-specific, not assessor-specific - any relevant professional can assess capacity. The five MCA principles are presumption, support, unwise decisions, best interests, and least restriction.
EQ-5D-5L measures quality of life across five dimensions at five levels - it generates utility values for QALY calculation and is NICE's preferred measure for health economic evaluation.
HoNOS-65+ is a 12-item clinician-rated scale for older adults - adapted from HoNOS with specific items for cognitive problems, ADLs, and living conditions relevant to elderly patients.
The C-SSRS assesses suicidal ideation severity, ideation intensity, suicidal behaviour, and lethality - it is FDA-recommended and provides standardised terminology distinguishing ideation from behaviour.
Section 136 allows police removal from a public place to a place of safety - 24 hours duration (extendable by 12), health-based settings preferred, purpose is assessment not treatment.
Section 5(4) is a 6-hour nurse's holding power for informal inpatients - exercisable by RMN/RNLD nurses only when a doctor is unavailable and the patient needs immediate restraint from leaving.
Mental Health Tribunals consist of legal, medical, and lay members - they must discharge if statutory criteria for detention are not met. Patients have time-limited rights to apply depending on their section.
Hoarding disorder is a distinct OCRD diagnosis - difficulty discarding possessions filling living spaces. It differs from OCD-related hoarding, has distinct neurobiology, and responds poorly to standard OCD treatments.