To investigate the efficacy and cognitive and psychomotor effects of venlafaxine and dothiepin in elderly patients with moderate major depression. A prospective, randomized, double-blind, parallel-group, active comparator controlled study was conducted. Eighty-eight patients (aged > or = 60 years) were enrolled. Each patient received either venlafaxine (immediate release formulation) 37.5 mg twice per day or dothiepin 25 mg mane followed by 50 mg nocte for 26 weeks. Efficacy was assessed with the Montgomery-Asberg Depression Rating Scale and the Hamilton Depression Rating Scale. A psychometric test battery to assess cognitive function, activities of daily living and sleep consisted of Critical Flicker Fusion (CFF), Short-term Memory--Kim's Game, Cognitive Failures Questionnaire, Milford Epworth Sleepiness Scale, Leeds Sleep Evaluation Questionnaire, and an Accident Scoring Questionnaire. Quality of Life Questionnaires (Short Form 36 and Quality of Life in Depression Scale) were also administered. Venlafaxine significantly (p < 0.05) raised CFF scores compared to baseline but had no effect on any other measure. Dothiepin significantly (p < 0.05) lowered CFF threshold, and increased ratings of both sedation and difficulty in waking. The results showed that venlafaxine at doses of 37.5 mg b.i.d. in elderly depressed patients is free from disruptive effects on cognitive function and psychomotor performance.