Personality disorder prevalence and correlates in a whole of nation dataset.

PURPOSE: The epidemiology of personality disorder is poorly understood. This study aims to describe the population in contact with mental health services with a diagnosis of personality disorder and compare service use between this group and those with a diagnosis of depression. METHODS: Investigation of a routinely collected clinical data set across New Zealand was conducted. We used data from 2008 to 2017 and 1-year data from 2016, the most complete dataset. This allowed for variation over the years and confirmation within a 1-year prevalence. These data were analysed focusing on patients with a primary diagnosis of any personality disorder and the subset with borderline personality disorder (BPD). BPD was chosen as the most common clinical personality disorder diagnosis and that most researched. RESULTS: 8884 (2.8%) of the population in contact with mental health services carried a primary diagnosis of personality disorder. Personality diagnosis other than antisocial personality disorder (ASPD) in men and borderline personality disorder (BPD) in either gender was negligible. Rates of personality pathology increased with social deprivation and were commonest in young adults. Multi-morbidity was the norm, with internalising disorder common. Maori diagnosed with PD were over-represented both in the patient group and by population. CONCLUSION: Borderline personality disorder and antisocial personality disorder are routinely diagnosed in routine clinical practice in New Zealand; however, other categorical diagnoses are not made. Patients with PD are significant users of resources in comparison to depressed patients. Resource utilisation was significantly greater in those with PD, in particular use of inpatient services compared to those with depression.