In this issue of the Archives, Yildiz et al1 report a 3-week, randomized, double-blind, placebo-controlled clinical trial to determine the antimanic efficacy of the centrally active protein kinase C (PKC) inhibitor tamoxifen citrate. The study was conducted in the inpatient psychiatric unit of a university medical center in Izmir, Turkey, and included 35 patients randomly assigned to tamoxifen and 31 to placebo. Patients were aged 18 to 60 years; had a diagnosis of bipolar disorder, currently in a manic or mixed state, with or without psychotic features (based on the Structured Clinical Interview for DSM-IV); and had Young Mania Rating Scale (YMRS) scores of more than 20
at baseline. Use of concomitant lorazepam was allowed up to 5 mg/d throughout the 3-week study duration. The study was completed by 83%
of patients randomly assigned to tamoxifen and 68% of those who received placebo. Tamoxifen-treated patients had mean decreases of 5.84 points per week on YMRS and 0.73 point per week on the Clinical Global Impressions–Mania Scale, compared with mean increases of 1.50 points per week on YMRS and 0.10 point per week on the Clinical Global Impressions–Mania Scale among placebo-treated patients. On both scales, tamoxifen-placebo comparisons differed significantly (P < .001).