Dropout in Psychotherapy for Personality Disorders: A Systematic Review of Predictors

INTRODUCTION: Dropout in psychotherapy for personality disorders is a major challenge, affecting treatment efficacy and mental health care delivery. Influenced by patient characteristics, therapist factors and treatment dynamics, dropout remains prevalent. This systematic review identifies predictors of psychotherapy dropout in individuals with personality disorders to inform strategies that enhance treatment engagement. METHOD: A systematic search in PsycINFO, PubMed and Scopus identified 22 studies from 1976 articles. Inclusion criteria required DSM/ICD-based personality disorder assessments and dropout predictors in psychotherapy. Non-English or non-peer-reviewed studies were excluded. Screening followed PRISMA guidelines using Rayyan, and study quality was assessed with the Newcastle-Ottawa Scale (NOS). RESULTS: Dropout rates ranged from 10.4% to 58%, depending on treatment modality and patient characteristics. Younger age, comorbid substance use disorders, emotional dysregulation, distress tolerance difficulties, childhood emotional abuse, therapist turnover and low motivation were significant predictors of dropout. Conversely, strong therapeutic alliances, mindfulness-based skills and engagement in phone coaching were associated with improved retention. Other relevant factors included low reflective functioning, lower education levels and socio-economic adversity, such as receiving disability benefits. Only one study identified low reflective functioning as a dropout predictor. Systemic factors, including treatment organization and care coordination, also played a crucial role. CONCLUSIONS: Addressing dropout requires early engagement strategies, therapist continuity and treatment flexibility. Enhancing therapeutic alliance and reflective functioning may be particularly effective in reducing dropout. Systemic improvements, such as better care coordination and accessibility, are crucial for sustaining engagement and improving psychotherapy outcomes for individuals with personality disorders. REGISTRATION: PROSPERO number: CRD42024509283.