Effect of diazepam on cognition via pupillometry

Continuous pupillary readings in response to a random-digit cognition task were obtained for 20 male subjects. Ten subjects were given 10 mg of diazepam, and 10 subjects were given placebos. Additional pupillary curves were recorded for both groups at 1 and 2 hr and compared to the initial curve. Subjects were required to repeat the exact sequence of verbalized randomized digits as a measure of performance. The results indicated that the diazepam treatment group differed significantly from the placebo group in terms of a depressed pupillary response. Furthermore, the performance recall measure was significantly reduced in the diazepam group. The relationships were clarified by an analysis of covariance and variance.