Key Facts

Anxiety disorders are characterised by excessive worry, fear, and associated behavioural disturbance. They are the most common mental health conditions and are frequently encountered in primary care. GAD is the most common type, but other anxiety disorders (panic disorder, social anxiety, specific phobias, agoraphobia) are also prevalent.

Epidemiology

• GAD prevalence: 5-6% (lifetime prevalence ~10%)
• Panic disorder: 1-2%
• Social anxiety disorder: 3-7%
• Anxiety disorders overall: 15-20% lifetime prevalence
• Female:male ratio 2:1
• Peak onset: late adolescence to early adulthood
• Comorbid depression: 50-60%

Aetiology

• Biopsychosocial model
• Biological: genetic predisposition (heritability 30-40%), GABAergic dysfunction, serotonergic dysfunction, HPA axis dysregulation
• Psychological: cognitive distortions (catastrophic thinking, overestimation of threat), conditioning, maladaptive coping
• Social: childhood adversity, life stressors, social deprivation, loneliness

Pathophysiology

• Overactive amygdala (threat detection centre) with reduced prefrontal cortical regulation
• Dysregulation of GABA (inhibitory) and glutamate (excitatory) neurotransmitter balance
• Chronic sympathetic nervous system activation (fight-or-flight)
• Altered serotonergic neurotransmission in raphe nuclei
• Locus coeruleus noradrenergic hyperactivity (panic disorder)

GAD

• Excessive, uncontrollable worry about multiple life domains (health, finances, family, work)
• Duration: most days for ≥6 months (DSM-5)
• Associated symptoms: restlessness, fatigue, poor concentration, irritability, muscle tension, sleep disturbance
• Physical symptoms: palpitations, sweating, tremor, GI symptoms, headache, dizziness

Panic Disorder

• Recurrent unexpected panic attacks: sudden surge of intense fear peaking in minutes
• Symptoms: palpitations, chest pain, breathlessness, dizziness, paraesthesiae, derealization, fear of dying
• Anticipatory anxiety and avoidance of situations where attacks occurred

Social Anxiety Disorder

• Marked fear of social/performance situations (scrutiny by others)
• Fear of embarrassment, humiliation, or negative evaluation
• Avoidance of social situations

Red Flags

• Suicidal ideation (anxiety is an independent risk factor for suicide)
• Severe functional impairment (unable to work, leave house)
• Substance misuse (self-medication with alcohol/benzodiazepines)
• Psychotic features (rare, suggests alternative diagnosis)
• Sudden onset in elderly (consider organic cause)

Screening Tools

• GAD-7: 7-item questionnaire; ≥8 clinically significant; ≥10 moderate; ≥15 severe
• PHQ-9: for comorbid depression
• SPIN (Social Phobia Inventory): for social anxiety disorder
• Panic Disorder Severity Scale: for panic disorder

Bloods (Exclude Organic Causes)

• TFTs: hyperthyroidism
• FBC: anaemia
• Glucose/HbA1c: hypoglycaemia/diabetes
• Calcium: hypercalcaemia
• ECG: if palpitations or cardiac symptoms

Special Tests

• 24h urinary metanephrines: if phaeochromocytoma suspected
• 24h Holter monitor: if cardiac arrhythmia suspected
• Drug/alcohol screening: if substance misuse suspected

NICE CG113 Stepped-Care Model

• Step 1: Psychoeducation, self-help resources, monitoring
• Step 2: Low-intensity interventions — guided self-help (based on CBT), psychoeducation groups, computerised CBT
• Step 3: CBT (12-15 sessions) OR SSRI medication, or combination
• Step 4: Specialist mental health services: complex/treatment-resistant cases, crisis care

Pharmacological

• First-line SSRI (NICE CG113):
  • Sertraline 50mg OD (unlicensed for GAD but NICE recommended; start 25mg to reduce initial anxiety)
  • Escitalopram 10mg OD (licensed for GAD)
  • Paroxetine 20mg OD (licensed for GAD, panic, social anxiety)
• Allow 4-6 weeks for therapeutic effect; increase dose if insufficient response at 4-6 weeks
• If first SSRI fails: switch to another SSRI or SNRI (venlafaxine 75-225mg OD)
• Continue for at least 12 months after remission
• Second-line: pregabalin 150-600mg/day (licensed for GAD); duloxetine 60-120mg OD
• Benzodiazepines: AVOID for routine use; maximum 2-4 weeks for acute crisis only; risk of dependence
• Buspirone: 5-HT1A agonist; alternative for GAD (limited availability)
• Beta-blockers (propranolol 10-40mg): for somatic symptoms (tremor, palpitations) in performance anxiety; NOT for underlying anxiety

Psychological Therapies

• CBT: gold standard; 12-15 sessions (individual or group); addresses cognitive distortions and avoidance behaviour
• Applied relaxation: alternative to CBT if preferred
• Self-help: books (e.g. 'Overcoming Anxiety' series), apps (e.g. SilverCloud, Beating the Blues)
• IAPT (Improving Access to Psychological Therapies): NHS talking therapies; self-referral available

Referral Criteria

• IAPT: for psychological therapy (Steps 2-3)
• Community mental health team: treatment-resistant anxiety (failed ≥2 adequate treatments), complex comorbidity, severe functional impairment
• Emergency/crisis: suicidal ideation, severe agitation, psychotic features

• CBT: response rate 50-60%; durable effects — may prevent relapse better than medication alone
• SSRIs: response rate 50-60%; relapse rate 25-30% after discontinuation
• GAD follows a chronic relapsing course in many patients; 25% achieve full remission at 2 years
• Panic disorder: good prognosis with CBT; 70-80% improvement
• Social anxiety disorder: tends to be chronic without treatment; CBT effective in 50-65%
• Comorbid depression worsens prognosis and should be treated concurrently
• Substance misuse complication: 20-30% of anxiety patients develop alcohol use disorder
• Early intervention improves long-term outcomes significantly

GAD-7 Scoring

Antidepressant Comparison for Anxiety Disorders

Panic Attack vs Panic Disorder