Key Facts

Personality disorders represent enduring patterns of cognition, affectivity, interpersonal functioning, and impulse control that are inflexible, pervasive, and lead to clinically significant distress or functional impairment.

Epidemiology

Prevalence in the general population is 4-13%. Personality disorders are present in 40-70% of psychiatric inpatients. BPD is the most commonly encountered in clinical settings (~2% prevalence). Antisocial PD affects ~3% of men and ~1% of women.

Aetiology

• Genetic: Heritability ~40-60%; strongest for antisocial and borderline PD
• Childhood adversity: Abuse, neglect, inconsistent parenting — strong association with BPD
• Attachment: Insecure attachment patterns, especially disorganised attachment
• Neurodevelopmental: Temperamental traits (high negative emotionality, low effortful control)

Pathophysiology

• BPD: Amygdala hyperreactivity, prefrontal cortex hypofunction, impaired mentalisation
• ASPD: Reduced amygdala and prefrontal cortex activation during moral decision-making; reduced autonomic reactivity
• Dimensional model (ICD-11): Personality functioning assessed on a spectrum of severity rather than categorical diagnoses
• Personality disorders represent the extreme end of normal personality trait distributions

Cluster A (Odd/Eccentric)

• Paranoid: Pervasive distrust, suspiciousness, misinterpretation of motives
• Schizoid: Detachment from social relationships, restricted emotional range
• Schizotypal: Cognitive/perceptual distortions, eccentric behaviour, social anxiety

Cluster B (Dramatic/Emotional)

• Borderline (EUPD): Emotional instability, impulsivity, unstable relationships, identity disturbance, self-harm, chronic emptiness, fear of abandonment
• Antisocial: Disregard for rights of others, impulsivity, deceitfulness, lack of remorse, conduct disorder before age 15
• Histrionic: Excessive emotionality, attention-seeking, suggestibility
• Narcissistic: Grandiosity, need for admiration, lack of empathy

Cluster C (Anxious/Fearful)

• Avoidant: Social inhibition, feelings of inadequacy, hypersensitivity to criticism
• Dependent: Excessive need for care, submissive behaviour, fear of separation
• Anankastic (OCPD): Preoccupation with orderliness, perfectionism, control (ego-syntonic, unlike OCD)

Red Flags

• Active self-harm or suicidal ideation — comprehensive risk assessment
• Forensic risk in antisocial PD — violence risk assessment
• Comorbid substance misuse — worsens outcomes significantly
• Personality disorder diagnosis in under-18s — use with extreme caution

Bedside

• Structured clinical assessment: Detailed personal history, relationship patterns, occupational history
• Self-report measures: PID-5 (Personality Inventory for DSM-5), SAPAS (Standardised Assessment of Personality — Abbreviated Scale)
• Risk assessment: Self-harm, suicide, violence
• Collateral history: Important for corroboration

Bloods

• TFTs, FBC, LFTs: Exclude organic causes of personality change
• Urine drug screen: Comorbid substance misuse

Special Tests

• Structured Clinical Interview for DSM-5 PD (SCID-5-PD): Gold standard research tool
• IPDE (International Personality Disorder Examination): Standardised interview
• Cognitive assessment: If neurodevelopmental condition suspected

Non-pharmacological

• BPD (NICE CG78):
  • Structured clinical management (SCM): Integrated approach combining case management with psychological therapy
  • Mentalisation-based treatment (MBT): 18 months; improves reflective functioning
  • Dialectical behaviour therapy (DBT): Skills training (mindfulness, distress tolerance, emotion regulation, interpersonal effectiveness)
  • Schema-focused therapy: Identifies early maladaptive schemas
• ASPD (NICE CG77): Group-based cognitive-behavioural programmes; therapeutic communities
• All PDs: Crisis planning, continuity of care, therapeutic relationship as key mechanism

Pharmacological

• No medication is licensed for personality disorders
• Short-term symptom management only:
  • SSRIs for comorbid depression/anxiety
  • Low-dose antipsychotics for transient psychotic symptoms or severe agitation (very short-term)
  • Avoid benzodiazepines — dependence risk, disinhibition
  • Avoid polypharmacy — review and rationalise

Referral Criteria

• BPD with recurrent self-harm — specialist personality disorder service
• ASPD with forensic risk — forensic psychiatry
• Complex comorbidity — specialist mental health team
• Consider neurodevelopmental assessment if ADHD/ASD suspected

• BPD: Improves with age — ~85% no longer meet diagnostic criteria by age 40-50; however functional recovery lags behind symptomatic improvement
• ASPD: Tends to attenuate with age, particularly impulsivity; but psychopathic traits persist
• Suicide: BPD lifetime suicide rate approximately 8-10%; highest risk in young adults
• Comorbidity: High rates of depression (75%), substance misuse (50-70%), anxiety disorders, eating disorders
• DBT: Reduces self-harm by ~50% compared to treatment as usual
• MBT: Significant improvements in interpersonal functioning, maintained at 8-year follow-up

ICD-11 Personality Disorder Model

Trait Qualifiers (ICD-11)