The effects on performance of two antidepressants, alone and in combination with diazepam.

1. Ninety healthy adult men participated in a study of the effects on performance of 60 mg fluoxetine, 50 mg amitriptyline or placebo, alone and in combination with 5 mg diazepam or placebo. 2. In a 2X3 factorial design study, groups of 15 Ss received one of six possible treatment combinations. 3. Ss were tested with a battery of laboratory tests at two post-dosing times. 4. Amitriptyline impaired the performance of all tasks. When diazepam was added to the amitriptyline treatment, the impairment of three tasks increased. Diazepam alone produced impairment on two measures. 5. Fluoxetine alone impaired no task; some impairment occurred with the fluoxetine-diazepam combination.