## Epidemiology of Cluster B Personality Disorders **Key Point:** Borderline Personality Disorder (BPD) is the most commonly diagnosed Cluster B personality disorder in clinical settings, with prevalence estimates of 1–2% in the general population and up to 10% in clinical samples. ### Prevalence Comparison | Personality Disorder | Prevalence in General Population | Clinical Setting Prevalence | Female:Male Ratio | |---|---|---|---| | Borderline | 1–2% | 8–10% | 3:1 | | Narcissistic | 0.5–1% | 2–5% | 1:1 | | Antisocial | 0.5–1% | 3–5% | 4:1 (male) | | Histrionic | 0.5–1% | 1–3% | 2:1 (female) | **High-Yield:** BPD accounts for the majority of Cluster B diagnoses in psychiatric hospitals and outpatient clinics, particularly among young adult females. ### Clinical Features Supporting BPD Diagnosis 1. **Affective instability** — rapid mood shifts within hours 2. **Interpersonal dysfunction** — intense fear of abandonment (real or imagined) 3. **Impulsivity** — spending, substance abuse, reckless driving, binge eating 4. **Identity disturbance** — unstable self-image and goals 5. **Chronic emptiness** — pervasive sense of void 6. **Suicidal/self-harm behavior** — present in ~75% of BPD patients 7. **Transient stress-related paranoia or dissociation** **Clinical Pearl:** The vignette's description of unstable relationships with idealization–devaluation cycles, impulsivity, and suicidal gestures triggered by perceived rejection is pathognomonic for BPD. **Mnemonic:** **ABCDEFG** for BPD features: - **A**bandonment fears - **B**lack-and-white thinking (splitting) - **C**hronic emptiness - **D**issociation/derealization - **E**motional instability - **F**rantic efforts to avoid abandonment - **G**estures/threats of self-harm [cite:DSM-5 Personality Disorders Section]
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