Comorbid early psychosis and borderline personality disorder: Conceptualizing clinical overlap, etiology, and treatment

Despite substantial efforts aimed at the detection and intervention for early symptoms of mental illness, there is relatively limited research on the clinical overlap between borderline personality disorder (BPD) and early psychosis, for example, clinical high risk (CHR) for psychosis, in young people. We present a narrative review of the clinical overlap between BPD and psychosis spectrum symptoms. Both conditions have unstable temporal course, and both are marked by functional impairment, increased suicide risk, and higher rates of psychiatric inpatient services. We then review evidence-based treatments for psychosis and BPD, emphasizing treatments for early presentations of these symptoms and initial research considering treatments for the overlap. Psychotherapies with the strongest empirical support include cognitive behavioral models, with BPD showing limited response to adjunctive pharmacotherapy. We end by discussing specific recommendations for future research, including longitudinal studies to determine the predictors of the course of illness and the development of treatments to target comorbid BPD and CHR symptoms.