Background: This study examines the therapeutic effect of fluoxetine, a selective serotonin reuptake inhibitor, added to dialectical behavior therapy (DBT), an empirically supported psychosocial therapy, for the treatment of borderline personality disorder.
Method: This is a 12-week, randomized, double-blind, placebo-controlled study of patients with borderline personality disorder (identified using the Structured Clinical Interview for DSM-IV Axis II Disorders). All subjects received individual and group DBT. Of the 20 subjects that completed treatment, 9 were randomly assigned to receive up to 40 mg/day of fluoxetine and 11 were randomly assigned to the placebo condition. Subjects were evaluated at baseline and at week 10 or 11 on self-report measures of depression, anxiety, anger expression, dissociation, and global functioning. The study was conducted between January 1998 and February 2000.
Results: Time-by-group interaction effects revealed no significant group differences in scores from pre-treatment to posttreatment on any measure. However, within the DBT/placebo group, there were significant pretreatment/posttreatment differences in the direction of improvement on all measures. No significant pre-treatment/posttreatment differences were found within the DBT/fluoxetine condition.
Conclusion: The data suggest that adding fluoxetine to an efficacious psychosocial treatment does not provide any additional benefits. Further studies with larger sample sizes are warranted.