Emotionally Unstable Personality Disorder with Comorbid Binge-Eating Disorder — A Comprehensive Review

Background: Borderline Personality Disorder (BPD) is a severe psychiatric condition characterised by affective instability, interpersonal dysfunction, and impulsivity. Binge-Eating Disorder (BED), the most prevalent eating disorder, involves recurrent binge episodes with loss of control and psychological distress. Despite growing evidence of substantial comorbidity between BPD and BED, this overlap remains underrecognized and undertreated. Methods: A narrative synthesis of peer-reviewed studies, meta-analyses, and clinical guidelines was conducted, focusing on epidemiological trends, shared mechanisms, clinical features, and treatment approaches relevant to the dual presentation of BPD and BED. Results: Epidemiological findings indicate that up to one-third of individuals with BED exhibit borderline features, while 20–30% of those with BPD meet criteria for an eating disorder. Shared etiological mechanisms include chronic emotion dysregulation, impulsivity (particularly negative urgency), and early-life trauma, with neurobiological evidence implicating fronto-limbic and reward circuitry. The co-occurrence of BPD and BED is associated with earlier onset, greater functional impairment, elevated suicidality, and poorer treatment response compared with either disorder alone. Psychotherapies such as Dialectical Behaviour Therapy (DBT) and Cognitive-Behavioural Therapy (CBT) show efficacy, though integrated, trauma-informed, and multidisciplinary interventions are increasingly recommended. Pharmacological treatments may provide symptomatic relief but are not first-line strategies. Conclusions: Comorbid BPD and BED represent a clinically significant yet under-addressed challenge. Improved recognition, integrative care models, and precision treatment are essential to enhance outcomes. Future research should prioritise large-scale epidemiological studies, mechanistic investigations, and clinical trials of hybrid or stepped-care interventions.