Personality Disorders
Summary
Personality disorders are enduring patterns of inner experience and behaviour that deviate markedly from cultural expectations, are pervasive and inflexible, have their onset in adolescence or early adulthood, are stable over time, and lead to distress or impairment. The DSM-5 and ICD-11 classify personality disorders into clusters based on shared features: Cluster A (Odd/Eccentric), Cluster B (Dramatic/Emotional), and Cluster C (Anxious/Fearful). The most clinically significant is Borderline Personality Disorder (BPD/EUPD), characterised by emotional dysregulation, unstable relationships, and self-harm. Treatment is primarily psychological, with Dialectical Behaviour Therapy (DBT) being the most evidence-based treatment for BPD. Medications may help with comorbid conditions but do not treat core personality pathology.
Key Facts
- Definition: Enduring maladaptive patterns of behaviour and inner experience
- Clusters: A (Mad), B (Bad), C (Sad)
- Most Common/Significant: Borderline (BPD/EUPD)
- Treatment: Psychological therapies (DBT, MBT, CBT)
- Medications: Treat comorbidities only — not core PD
- Prognosis: Symptoms often improve with age
Clinical Pearls
"Cluster A, B, C = Mad, Bad, Sad": Memory aid for the three clusters.
"DBT is the Gold Standard for BPD": Dialectical Behaviour Therapy has the strongest evidence base.
"Medications Don't Fix PD": Medications can help comorbid depression or anxiety, but don't treat the core personality disorder.
"Crisis Plans Save Lives": Patients with BPD benefit from clear crisis plans developed collaboratively.
Prevalence
- 10-15% of general population
- Higher in psychiatric settings (30-50%)
By Cluster
| Cluster | Prevalence |
|---|---|
| Cluster A | 3-5% |
| Cluster B | 3-5% |
| Cluster C | 5-10% |
BPD
- 1-2% of population
- 75% female (may be underdiagnosed in males)
Aetiology
- Genetic: Heritability 40-60%
- Environmental: Childhood trauma, Neglect, Abuse, Attachment disruption
- Neurobiology: Amygdala hyperactivity (BPD), Prefrontal hypoactivity
Cluster A (Odd/Eccentric)
| Disorder | Features |
|---|---|
| Paranoid | Distrust, Suspiciousness, Grudge-bearing |
| Schizoid | Detachment, Solitary, Flat affect, Limited emotional range |
| Schizotypal | Eccentric, Magical thinking, Ideas of reference, Social anxiety |
Cluster B (Dramatic/Emotional)
| Disorder | Features |
|---|---|
| Antisocial (ASPD) | Disregard for others, Deceit, Aggression, Irresponsibility, Conduct disorder history (before 15) |
| Borderline (BPD/EUPD) | Emotional dysregulation, Unstable relationships, Identity disturbance, Self-harm, Abandonment fears |
| Histrionic | Attention-seeking, Theatrical, Excessive emotionality |
| Narcissistic | Grandiosity, Need for admiration, Lack of empathy |
Cluster C (Anxious/Fearful)
| Disorder | Features |
|---|---|
| Avoidant | Social inhibition, Feelings of inadequacy, Hypersensitivity to criticism |
| Dependent | Excessive need to be cared for, Submissive, Fear of separation |
| Obsessive-Compulsive (OCPD) | Preoccupation with orderliness, Perfectionism, Control (distinct from OCD) |
Mental State Examination
- Appearance and behaviour
- Mood and affect (often dysregulated in BPD)
- Thought content (paranoid in A, identity disturbance in BPD)
- Insight (variable)
Risk Assessment
- Self-harm and suicide risk (especially BPD)
- Risk to others (especially ASPD)
- Exploitation risk (Narcissistic, Antisocial)
Diagnosis is Clinical
- No blood tests or imaging
- Structured Clinical Interview (SCID-II) or PDQ-4 for research
Rule Out
- Organic causes (TBI, substance use)
- Other psychiatric disorders (Mood disorders, Psychosis)
General Principles
┌──────────────────────────────────────────────────────────┐
│ PERSONALITY DISORDERS MANAGEMENT │
├──────────────────────────────────────────────────────────┤
│ │
│ PSYCHOLOGICAL THERAPIES (FIRST-LINE): │
│ │
│ BORDERLINE PD (BPD/EUPD): │
│ • Dialectical Behaviour Therapy (DBT) — Best evidence │
│ • Mentalisation-Based Therapy (MBT) │
│ • Schema-Focused Therapy │
│ • Transference-Focused Psychotherapy │
│ │
│ OTHER PDs: │
│ • CBT (Cluster C) │
│ • General psychotherapy │
│ │
│ MEDICATION (FOR COMORBIDITIES ONLY): │
│ • SSRIs (depression, anxiety) │
│ • Low-dose antipsychotics (short-term, crisis) │
│ • Mood stabilisers (mood instability — limited evidence)│
│ • ⚠️ No medication treats core PD │
│ │
│ CRISIS PLANNING (BPD): │
│ • Collaboratively developed safety plan │
│ • Clear escalation pathway │
│ • Reduce risk of repeated presentations │
│ │
│ SERVICE STRUCTURE: │
│ • Specialist PD services (where available) │
│ • Community Mental Health Teams │
│ • Avoid unhelpful repeated admissions │
│ │
└──────────────────────────────────────────────────────────┘
Of Personality Disorders
- Self-harm (especially BPD)
- Suicide (8-10% BPD)
- Substance misuse
- Relationship breakdown
- Unemployment
- Criminal behaviour (ASPD)
Of Treatment
- Therapeutic ruptures
- Therapy dropout
- Polypharmacy (avoid)
Natural History
- Symptoms often improve with age (especially BPD)
- Many achieve remission by age 40
With Treatment
- DBT significantly reduces self-harm and hospital admissions in BPD
Key Guidelines
- NICE CG78: Borderline Personality Disorder (2009)
- NICE CG77: Antisocial Personality Disorder (2009)
Key Evidence
DBT
- RCT evidence for reduced self-harm, suicidality, and hospitalisations
What is a Personality Disorder?
A personality disorder is a long-term pattern of thinking, feeling, and behaving that differs significantly from what is expected. It can cause problems in relationships, work, and daily life.
What Are the Types?
There are three "clusters":
- Cluster A (Odd/Eccentric): Paranoid, Schizoid, Schizotypal
- Cluster B (Dramatic/Emotional): Antisocial, Borderline, Histrionic, Narcissistic
- Cluster C (Anxious/Fearful): Avoidant, Dependent, Obsessive-Compulsive
What Causes It?
A mix of genetics, brain development, and experiences in childhood (like trauma or neglect).
How is It Treated?
- Talking therapies (like DBT for borderline PD) are the main treatment
- Medications can help with symptoms like depression or anxiety, but don't treat the personality disorder itself
Is There Hope?
Yes! Many people with personality disorders improve with the right support. Symptoms often get better with age.
Primary Guidelines
- NICE. Borderline Personality Disorder: Recognition and Management (CG78). 2009. nice.org.uk/guidance/cg78
Key Studies
- Linehan MM, et al. Dialectical behavior therapy for high suicide risk in individuals with borderline personality disorder. JAMA Psychiatry. 2015;72(5):475-482. PMID: 25806661