Incidence and prevalence rates of personality disorders in Denmark-A register study

Abstract

Background: Personality disorders (PDs) are prevalent in about one in every 10 adults. Prior to the introduction of the ICD-10 in Denmark, the incidence rate for PD (including schizotypal) among psychiatric patients was approximately 12% and the prevalence rate 14%.

Aims: The aim of the present clinical epidemiology study is to investigate the use of ICD-10 PD as primary and secondary diagnoses in years 1995, 2000 and 2006, comorbid disorders and their relation to age and gender.

Methods: The study includes all adult patients admitted to any psychiatric hospital (inpatients and outpatients) in Denmark.

Results: Both incidence and prevalence rates of PD diagnoses decrease over the study period. It is evident that all specific diagnoses significantly decrease or remain stable whereas the unspecified and mixed type significantly increases constituting up to 50% of diagnoses. Emotionally unstable PD stands out as the single most prevalent covering around one third of PD diagnoses. A decrease is found in the prevalence of patients receiving a PD diagnosis as a primary diagnosis, but an increase as a secondary diagnosis (most often as comorbid to depression or anxiety disorder). Differences are found in relation to gender and age.

Conclusion: PDs are among the most prevalent disorders; however, rates are decreasing in psychiatric settings. There seem to be a rather huge gap between clinical evaluation and research data on prevalence of PDs. Clinicians need more education and sufficient time for in-depth personality assessment of PDs in all patient groups.

Keywords: Comorbidity; Diagnostic practice; Incidence; Personality disorders; Prevalence.