Borderline personality disorder (BPD) is a complex mental disorder of instability in affect regulation, impulse control, interpersonal relationships and self-image. Comorbidity is common both within other personality disorders and other psychiatric disorders.

The Danish Psychiatric Central Research Register (DPCRR) is nationwide and makes it possible to follow psychiatric patients over long periods. Thus the DPCRR can bring in new understandings of comorbidity in BPD patients and their former and future morbidity.

To determine the psychiatric comorbidity profile of Danish psychiatric inpatients diagnosed with BPD from 1970 through 2012, and analyse the diagnostic profile before and after the first diagnosis of BPD.

All first time-ever diagnoses of BPD among psychiatric inpatients were identified in the DPCRR from 1970 through 2012. Information of their previous and future admissions were grouped in accordance with ICD-10.

A total of 23,221 persons diagnosed with BPD was identified in the DPCRR between 1970 and 2012, 73.1% female.

The must prevalent co-occuring diagnosis is substance abuse present in 12% of the patients. Depressive disorders are present in 23% of previous admissions, 27% of future and co-occur for 9%. Bipolar disorders are present in 2% of previous admissions, 7% of future and cooccur for less than 1%. PTSD and ADHD co-occur and are present in previous and future admissions for less than 5%.

In progress.