The effects of alprazolam (0.125 mg) taken twice a day on several cognitive and performance tasks (Pictures test, Digit-Symbol Substitution Test, Choice Reaction Time [CRT], Critical Flicker Fusion [CFF]) were investigated in healthy students. A double-blind, independent group design was used to compare placebo with alprazolam (32 volunteers in each group). After random assignment, all subjects received placebo for 3 days (D) followed by 14 days of treatment with either alprazolam or placebo. Subjects completed a battery of tests at D0, D3, D7, D10, and D14.
D3 performance was poorer in the alprazolam group except for CFF values (ascending values and total values), and the only significant improvement was in total reaction time on the CRT test.However, a significant improvement in performance (except in recognition reaction time) was shown at D7, D10, and D14 in the alprazolam group compared with the control group results. This study shows that repeated low doses of alprazolam produce small improvements in some aspects of psychomotor and cognitive functions. Training effect, tolerance effect, anxiolytic effect, and changes in receptor function and/or number are discussed to explain the performance improvement. (J Clin Psychopharmacol 1998;18:364-372)