Personality disorder prevalence in psychiatric outpatients: a systematic literature review.

INTRODUCTION: A systematic literature review of studies measuring the prevalence of personality disorder in community secondary care is needed to identify both the met and unmet needs and plan services accordingly. METHODS: PsycINFO, MEDLINE and EMBASE databases were searched using NHS Evidence. Only studies assessing overall personality disorder prevalence within help-seeking, outpatient populations were included. Papers were excluded for focusing solely on the prevalence of specific personality disorders or comorbid prevalence within specific populations. RESULTS: A total of 269 papers were identified. Nine papers met criteria and were critically appraised, showing a high level of heterogeneity with regards to methods, inclusion criteria, source of information, time of assessment, instruments used and overall quality of research. Prevalence estimates in Europe varied between 40% and 92%, were more consistently approximated between 45% and 51% in the USA and differed significantly in the two Asian studies: 1.07% (India) and 60% (Pakistan). CONCLUSIONS: The prevalence of personality disorder in community mental health care appears to be substantial, but better estimates will only emerge from high quality studies with greater consistency of method. Implementing screening tools within outpatient or community services may result in high rates of personality disorder identification, with both clinical and service implications.