A 28-year-old woman is admitted to the psychiatry ward following a suicide attempt with wrist laceration after her boyfriend ended their relationship. She reports a lifelong pattern of intense, unstable relationships with rapid shifts from idealization to devaluation. She describes a chronic sense of emptiness and engages in impulsive behaviors including binge eating, substance misuse, and unprotected sexual encounters. She has frequent episodes of intense anger that she struggles to control and often directs at staff. She denies hallucinations or delusions. She reports fear of abandonment and makes repeated threats of self-harm when she perceives rejection. What is the most likely personality disorder diagnosis?

Explanation

## Diagnosis: Borderline Personality Disorder (BPD) ### Core Features of BPD (DSM-5 Criterion A) **Key Point:** BPD is defined by a pervasive pattern of instability in interpersonal relationships, self-image, and affect, plus marked impulsivity. A minimum of 5 of 9 criteria must be met; this patient exhibits at least 7. ### DSM-5 Criteria Met | Criterion | Patient Evidence | |-----------|------------------| | Frantic efforts to avoid abandonment | Fear of abandonment; threats of self-harm when perceiving rejection | | Unstable relationships | Rapid idealization-devaluation cycles | | Unstable self-image | Chronic sense of emptiness | | Impulsive behaviors (≥2 areas) | Binge eating, substance misuse, unprotected sex | | Recurrent suicidal behavior | Suicide attempt with wrist laceration | | Affective instability | Frequent episodes of intense anger | | Chronic emptiness | Explicitly reported | | Inappropriate, intense anger | Frequent episodes; difficulty controlling; directed at staff | ### Pathognomonic Features **High-Yield:** The **splitting** defense mechanism is pathognomonic for BPD: rapid shifts from idealization ("he is perfect") to devaluation ("he is all bad") in response to perceived rejection. This is NOT seen in other Cluster B disorders. **Mnemonic for BPD: SHARP-DIME** - **S**uicide/Self-harm (recurrent) - **H**yperactive anger (inappropriate, intense) - **A**bandonment fears (frantic efforts to avoid) - **R**elationships (unstable and intense) - **P**erfectionism (unstable self-image) - **D**iscontrol (impulsive behaviors) - **I**dentity disturbance (chronic emptiness) - **M**ood instability (affective lability) - **E**mptiness (chronic) ### Cluster B Overview | Disorder | Core Feature | Key Difference from BPD | |----------|--------------|------------------------| | **Borderline** | Instability + abandonment fear + self-harm | Splitting; fear of abandonment | | **Narcissistic** | Grandiosity + entitlement + lack of empathy | No fear of abandonment; no self-harm | | **Histrionic** | Excessive emotionality + attention-seeking | Stable relationships; no chronic emptiness | | **Antisocial** | Deceitfulness + aggression + lack of remorse | No suicidality; no abandonment fear | ### Why Not Histrionic? Histrionic personality disorder features excessive emotionality and attention-seeking, but relationships are typically stable (though superficial). Histrionic individuals do NOT exhibit chronic emptiness, recurrent self-harm, or the fear of abandonment that drives BPD. Histrionic anger is reactive to perceived slights; BPD anger is intense, poorly controlled, and often self-directed. ### Clinical Pearl **Clinical Pearl:** BPD is the most common personality disorder in clinical settings (10% of outpatients, 20% of inpatients). It is 5–10 times more common in first-degree relatives of individuals with BPD, suggesting genetic vulnerability. Dialectical Behavior Therapy (DBT) is the gold-standard psychotherapy. [cite:Harrison 21e Ch 397] ### Neurobiology **Warning:** BPD is NOT a psychotic disorder. Patients do not have hallucinations or delusions (as this patient appropriately denies). The instability and impulsivity reflect dysregulation of limbic-prefrontal circuits, particularly involving serotonin and dopamine.