Dissociative identity disorder (DID) is often accompanied by suicidal behavior. However, systematic research regarding suicide attempts in DID is rare.

Aims of this study were to examine frequency, characteristics and risk factors for suicidal behavior in DID patients.

A sample of outpatients and day care patients with (n=17) and without DID (n=34) from psychiatric outpatient and day care units and a private practice located in Switzerland were assessed at baseline and at 12-month follow-up. At baseline, Axis I and Axis II disorders according to DSM-IV were ascertained with the Structured Clinical Interview for DSM-IV Axis I disorders (SCID-I), the Structured Clinical Interview for DSM-IV Axis II disorders (SCID-II), and the Structured Clinical Interview for DSM-IV Dissociative Disorders (SCID-D-R). Suicidal behavior during a 12-month period following the baseline assessment was assessed using the Longitudinal Interval Follow-Up Evaluation interview.

We found that 23.5% of subjects with DID and 0% of subjects without DID attempted at least one suicide during the 12-month period of observation (P=0.010). Medical threat of most suicide attempts was moderate to severe. Potential risk factors for suicidal behavior in DID subjects were a comorbid substance disorder or posttraumatic stress disorder, high number of any Axis I disorder, higher education, and foreign nationality.

Our results support previous evidence for a high risk of suicide attempts in patients with DID. The potential risk factors for suicidal behavior in DID subjects correspond largely to known risk factors for suicide in general population and mental disorders other than DID. The results emphasize the importance of assessing suicidal intentions when treating DID patients.