Evaluation of the effects of clobazam, A 1,5 benzodiazepine, on mood and psychomotor performance in clinically anxious patients in general practice.

1 The methodology of clinical trails of anxiolytic drugs carried out in general practice conditions is discussed. Particular problems include: the selection of suitable patients; placebo effects; the influence of non-specific variables such as life-events; and patient compliance. 2 Clobazam, a novel 1,5 benzodiazepine, and diazepam were compared with placebo in a double-blind group comparative trial in general practice, which was designed to avoid as many confounding variables as possible. Anxiety-reducing effects were evaluated and at the same time the effects of the drugs on psychomotor performance were examined. 3 Both clobazam and diazepam produced significant improvements in anxiety ratings on the Hamilton Anxiety Scale and the Morbid Anxiety Inventory, whereas placebo did not. 4 The placebo group demonstrated a significant improvement in performance on a pursuit rotor and digit symbol substitution test (DSST), whereas the diazepam group's performance did not change. The clobazam group showed improvement in both tests, significantly so in the DSST. This suggests that diazepam produces impairment in performance, which had negated the practice effects seen in the placebo group, whereas clobazam did not seem to produce similar impairment.