Cluster B Personality Disorders: Borderline, Histrionic, and Narcissistic Presentations in Clinical Practice. A Systematic Literature Review of Diagnostic Criteria, Evidence-Based Treatments, and Cultural Considerations

Cluster B personality disorders, comprising Borderline Personality Disorder (BPD), Histrionic Personality Disorder (HPD), and Narcissistic Personality Disorder (NPD), represent pervasive patterns of dramatic, emotional, and erratic functioning that profoundly disrupt interpersonal relationships, self-identity, and emotional regulation. These conditions affect approximately 1.5% to 5.9% of the general population globally. This systematic literature review synthesizes diagnostic criteria from the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR), clinical phenomenology, differential diagnostic frameworks, evidence-based psychotherapeutic interventions, and etiological models with particular emphasis on empirical meta-analyses and neuroimaging findings. Key findings reveal shared diathesis-stress pathways involving genetic vulnerabilities, early adversity, and fronto-limbic dysregulation across these disorders. Disorder-specific treatments demonstrate differential efficacy: Dialectical Behavior Therapy (DBT) for BPD yields effect sizes ranging from d = 0.5 to 1.0 for reductions in suicidality, while Schema Therapy and Mentalization-Based Treatment show promise for identity disturbance and affective instability. In African contexts, particularly Kenya, cultural stigma surrounding mental illness and communal relational norms may exacerbate symptom presentations, underscoring the imperative for culturally adapted interventions. Findings advocate for dimensional assessment frameworks consistent with the International Classification of Diseases, Eleventh Revision (ICD-11), integrated multimodal therapies, and culturally informed clinician training to mitigate the substantial suicide risk associated with BPD (approaching 10% lifetime prevalence) and reduce societal costs. Implications for marriage and family therapy practice in collectivist cultural contexts are discussed.