A 28-year-old man is referred to psychiatry by his general practitioner after presenting with recurrent relationship failures and occupational instability. He reports intense, unstable relationships with frequent angry outbursts directed at partners who he feels have betrayed him. He describes a chronic sense of emptiness and engages in impulsive spending, binge eating, and occasional self-harm (cutting) when distressed. He has made two suicide attempts in the past 2 years following perceived rejections. He alternates between idealizing and devaluing people in his life. He denies hallucinations or delusions. What is the most likely diagnosis?

Explanation

## Diagnosis: Borderline Personality Disorder ### Core Features of Borderline Personality Disorder (BPD) **Key Point:** Borderline personality disorder is a **Cluster B disorder** (dramatic, emotional, erratic) characterized by a pervasive pattern of instability in interpersonal relationships, self-image, and affect, combined with marked impulsivity. This patient demonstrates all five diagnostic domains: 1. **Affective instability** — intense, rapidly shifting emotions; chronic emptiness 2. **Impulsivity** — self-harm, binge eating, impulsive spending 3. **Unstable relationships** — idealization and devaluation (splitting) 4. **Intense fear of abandonment** — suicide attempts following perceived rejections 5. **Anger dyscontrol** — frequent, intense, inappropriate anger ### DSM-5 Diagnostic Criteria (≥5 of 9) | Criterion | Present in Case? | |-----------|------------------| | Frantic efforts to avoid abandonment (real or imagined) | ✓ (suicide attempts after rejection) | | Unstable, intense relationships alternating idealization–devaluation | ✓ (splitting behavior) | | Unstable self-image or self-concept | ✓ (chronic emptiness) | | Recurrent self-harm, suicidal behavior, threats, or self-injurious behavior | ✓ (cutting, 2 suicide attempts) | | Affective instability due to marked reactivity of mood | ✓ (intense, rapid mood shifts) | | Chronic feelings of emptiness | ✓ (explicitly stated) | | Inappropriate, intense anger or difficulty controlling anger | ✓ (frequent angry outbursts) | | Transient, stress-related paranoid ideation or severe dissociation | Not mentioned | | Impulsive behaviors in ≥2 areas that are potentially self-damaging | ✓ (spending, binge eating, self-harm) | ### Cluster B Classification **High-Yield:** Borderline PD is a **Cluster B disorder** (dramatic, emotional, unpredictable). Other Cluster B disorders: - **Antisocial PD** — callousness, deceitfulness, lack of remorse, violation of others' rights - **Narcissistic PD** — grandiosity, entitlement, lack of empathy - **Histrionic PD** — excessive emotionality, attention-seeking, shallow relationships ### Mnemonic: DESPERATE **Mnemonic:** **D**ysfunctional relationships, **E**motional instability, **S**elf-harm, **P**erfectionism (unstable self-image), **E**mptiness, **R**age, **A**bandonment fears, **T**ransient psychosis (stress-related), **E**xcessive impulsivity ### Clinical Pearl: Splitting **Clinical Pearl:** The alternation between idealizing and devaluing others ("splitting") is pathognomonic for BPD. This reflects the patient's inability to integrate positive and negative qualities in a single person — a primitive defense mechanism. ### Epidemiology & Prognosis - **Prevalence:** ~1–2% in the general population; ~10% in psychiatric inpatients - **Gender:** More common in women (3:1 female-to-male ratio) - **Onset:** Late adolescence to early adulthood (as in this case) - **Course:** Symptoms often peak in the 20s–30s; ~50% achieve remission by age 40 - **Suicide risk:** 8–10% of patients die by suicide ### Treatment Approach 1. **Psychotherapy** — Dialectical Behavior Therapy (DBT) is the gold standard 2. **Pharmacotherapy** — No specific medication; SSRIs for mood/anxiety, antipsychotics for transient psychosis 3. **Hospitalization** — Reserved for acute suicidality or severe self-harm [cite:DSM-5 Personality Disorders; Kaplan & Sadock's Synopsis of Psychiatry 11e Ch 21]