Cognition and vigilance: differential effects of diazepam and buspirone on memory and psychomotor performance

Effects of a single dose of the anxiolytic buspirone (15 mg) on memory and psychomotor performance were studied in healthy volunteers and compared to those of the classic benzodiazepine anxiolytic diazepam (15 mg). The study was performed in a double-blind, placebo-controlled way. Three groups of 12 subjects were exposed to an extended test battery before and after intake of drug or placebo. Next to this, an evaluation session took place 1 week later. Immediately after intake, diazepam exerted major effects on memory, impaired psychomotor performance and decreased alertness. In particular, long-term memory had deteriorated, which was interpreted as anterograde amnesia. One week later, more items were recalled from the predrug session compared to the number of items from the postdrug session; this was interpreted as retrograde facilitation. After intake of buspirone, there were no effects of alertness and vigilance, on psychomotor performance and on memory. One week later, a small memory decrement was noticed for verbal material, which was considered as a sign of anterograde amnesia. These results indicate that effects of anxiolytics on memory can be more easily demonstrated 1 week later than immediately after drug intake and, furthermore, that the disruptive effects of diazepam outweight the small effects of buspirone. Finally, it was established that the effects of diazepam on cognition might be mediated by its effects on alertness and vigilance and that cognitive effects are not related to the anxiolytic properties of the drug.