A Comparison of the Anxiolytic Properties of Tofisopam and Diazepam: A Double-Blind, Randomized, Crossover, Placebo-Controlled Pilot Study

New clinical reports have recently been published on tofisopam-an anxiolytic drug currently registered as a benzodiazepine-after a long break in this research area. Neurobiological studies concerning its properties, which differ from those of benzodiazepines, are underway. The analyses presented in this study aimed to compare the effects of tofisopam, diazepam, and a placebo in the treatment of anxiety symptoms. A total of 66 outpatients (43 women and 23 men) with generalized anxiety disorder aged 19 to 74 years (M = 41.4; SD = 13.2) were randomized in three groups receiving (1) tofisopam (50 mg three times a day), (2) diazepam (5 mg three times a day), or (3) a placebo for 2 weeks. Then, throughout a 2-week washout period, the patients were monitored for withdrawal symptoms. During the last 2 weeks, the effects of tofisopam (50 mg three times a day) and diazepam (5 mg three times a day) were compared (crossover design). The mean improvement on the Hamilton Anxiety Rating Scale was significantly higher in both the tofisopam and diazepam groups compared to the placebo group. There were no significant differences between the effects of diazepam and tofisopam, whereas adverse effects and withdrawal symptoms occurred less frequently in the tofisopam group. Tofisopam did not impair cognitive abilities, and related withdrawal symptoms resembled those of the placebo. If larger future studies corroborate these findings, tofisopam should be classified as a homophtalazine.