ContextThe place of long-term psychodynamic psychotherapy (LTPP) within psychiatry is controversial. Convincing outcome research for LTPP has been lacking.Objective To examine the effects of LTPP, especially in complex mental disorders, ie, patients with personality disorders, chronic mental disorders, multiple mental disorders, and complex depressive and anxiety disorders (ie, associated with chronic course and/or multiple mental disorders), by performing a meta-analysis.

Short-term psychodynamic psychotherapy proved to be an effective treatment in psychiatric disorders. However, further research of STPP in specific psychiatric disorders is needed, including a study of the active ingredients of STPP. Effectiveness studies should be included.

Results suggest that LTPP is superior to less intensive forms of psychotherapy in complex mental disorders. Further research on long-term psychotherapy is needed, not only for psychodynamic psychotherapy, but also for other therapies.

BackgroundPersonality disorder is a severe health issue. However, the epidemiology of personality disorders is insufficiently described and surveys report very heterogeneous rates. AimsWe aimed to conduct a meta-analysis on the prevalence of personality disorders in adult populations and examine potential moderators that affect heterogeneity. MethodWe searched PsycINFO, PSYNDEX and Medline for studies that used standardised diagnostics (DSM-IV/-5, ICD-10) to report prevalence rates of personality disorders in community populations in Western countries. Prevalence rates were extracted and aggregated by random-effects models. Meta-regression and sensitivity analyses were performed and publication bias was assessed. ResultsThe final sample comprised ten studies, with a total of 113 998 individuals. Prevalence rates were fairly high for any personality disorder (12.16%; 95% CI, 8.01-17.02%) and similarly high for DSM Clusters A, B and C, between 5.53 (95% CI, 3.20-8.43%) and 7.23% (95% CI, 2.37-14.42%). Prevalence was highest for obsessive-compulsive personality disorder (4.32%; 95% CI, 2.16-7.16%) and lowest for dependent personality disorder (0.78%; 95% CI, 0.37-1.32%). A low prevalence was significantly associated with expert-rated assessment (versus self-rated) and reporting of descriptive statistics for antisocial personality disorder. ConclusionsEpidemiological studies on personality disorders in community samples are rare, whereas prevalence rates are fairly high and vary substantially depending on samples and methods. Future studies investigating the epidemiology of personality disorders based on the DSM-5 and ICD-11 and models of personality functioning and traits are needed, and efficient treatment should be a priority for healthcare systems to reduce disease burden. Declaration of interestNone.