The outcomes of psychotherapy in mixed features personality disorders: a systematic review

Abstract Mixed features personality disorders (PDs) are highly prevalent and associated with significant burden of disease. Despite that, it has been an overlooked diagnostic category with respect to clinical research. This study aims to review empirical evidence about psychotherapy delivery available for these patients. We present a systematic review of clinical trials investigating the outcomes of psychotherapeutic interventions in adults with a primary diagnosis of mixed features PDs. Data were obtained from Medline/PubMed, Embase and PsycINFO. Seven studies met inclusion criteria; in one of them the whole sample was of this diagnostic group; two studies analysed psychotherapeutic intervention outcomes in this population, among other types of PDs, yet drawing specific conclusions on mixed features PDs patients; remaining studies addressed patient samples with different PDs types, mixed features included, where specific findings in this group of patients were not described - nonetheless, they included representative numbers of subjects with the diagnosis of interest. Available studies suggest that mixed features personality pathology per se does not seem to be an impediment to benefit from psychotherapeutic treatment, and improvement in different areas of life is possible for patients undergoing psychotherapy. The extant literature is marked by multiple challenges and inconsistencies across studies.