New onsets of substance use disorders in borderline personality disorder over 7 years of follow-ups: findings from the Collaborative Longitudinal Personality Disorders Study.

AIMS The purpose of this study was to examine whether patients with borderline personality disorder (BPD) have a higher rate of new onsets of substance use disorders (SUD) than do patients with other personality disorders (OPD). DESIGN This study uses data from the Collaborative Longitudinal Personality Disorder Study (CLPS), a prospective naturalistic study with reliable repeated measures over 7 years of follow-up. SETTING Multiple clinical sites in four northeastern US cities. PARTICIPANTS A total of 175 patients with BPD and 396 patients with OPD (mean age 32.5 years) were assessed at baseline and at 6, 12, 24, 36, 48, 60, 72 and 84 months. MEASUREMENTS The Structured Clinical Interview for DSM-IV Axis I Disorders and the Diagnostic Interview for DSM-IV Personality Disorders were used at baseline, the Follow-Along version of the DIPD-IV and the Longitudinal Interval Follow-up Evaluation at the follow-up evaluations. Kaplan-Meier analyses were calculated to generate the time to new onsets. FINDINGS BPD patients showed a shorter time to new onsets of SUD. Thirteen per cent of BPD patients developed a new alcohol use disorder and 11% developed a new drug use disorder, compared to rates of 6% and 4%, respectively, for OPD. Non-remitted BPD and remitted BPD patients did not differ significantly in rates of new onsets of SUD. CONCLUSIONS BPD patients have a high vulnerability for new onsets of SUDs even when their psychopathology improves. These findings indicate some shared etiological factors between BPD and SUD and underscore the clinical significance of treating SUD when it co-occurs in BPD patients.