Personality disorders, characterised by pervasive emotional and interpersonal dysfunction, are integral to psychiatric practice. This service review estimated the prevalence of personality disorders in a psychiatric inpatient setting and looked at various clinical and demographic factors of interest.

Data were retrospectively collected from 526 patients discharged from St Patrick’s University Hospital in 2019–2020 under the care of two consultant-led teams. Demographic and clinical data such as age of first mental health contact, number of previous admissions, and risk history were recorded as well as the use of the Structured Clinical Interview for DSM-5 Personality Disorders (SCID-5-PD).

37% of the sample had at least one personality disorder, with borderline (24.9%), avoidant (13.3%) and obsessive-compulsive (7.6%) being the most common subtypes. Notably, in 72.1% of cases the diagnosis was new. High comorbidity was observed, particularly with affective (47.7%) and anxiety disorders (28.4%). Patients with personality disorders exhibited high rates of self-harm (45%) and suicide attempts (40%).

The review highlighted potential delays in diagnosis, with an average of 15 years of mental health service contact prior to diagnosis. The findings underscore the need for specialised services and further research to better understand and manage personality disorders in the Irish psychiatric setting. Limitations include the specific sample from a private mental health facility and the high use of structured interviews, which may affect the generalisability of the results to other settings. This review contributes valuable data to the limited research on personality disorder prevalence in Irish psychiatric services.