Fluoxetine therapy in depersonalisation disorder: Randomised controlled trial

Background: Despite anecdotal reports that serotonin reuptake inhibitors may improve depersonalisation, there is no proven efficacious treatment for depersonalisation disorder. Aims: To investigate the efficacy of fluoxetine in the treatment of depersonalisation disorder. Method: Fifty-four people who met DSM-IV criteria for depersonalisation disorder were recruited through newspaper advertisements, and 50 were randomised to a 10-week, double-blind trial of fluoxetine 10-60 mg/day or placebo. Primary outcome measures were the Dissociative Experiences Scale - Depersonalisation Factor, the Depersonalization Severity Scale and the Clinical Global Impression - Improvement (CGI-1) scale. Results: Intention-to-treat analysis revealed that fluoxetine (mean dosage 48 mg/day) was not superior to placebo except for a clinically minimal but statistically significantly greater improvement in CGI-1 score in the fluoxetine group prior to covarying for anxiety and depression (2.9 v. 3.6). Depersonalisation was significantly more likely to improve if comorbid anxiety disorder improved. Conclusions: Fluoxetine was not efficacious in treating depersonalisation disorder, despite the commonly reported clinical use of serotonin reuptake inhibitors for this condition.