The effects of acute treatment with paroxetine, amitriptyline, and placebo on driving performance and cognitive function in healthy Japanese subjects: a double-blind crossover trial.

OBJECTIVE To assess the effects of antidepressants on driving performance from a different methodological viewpoint in light of the recent traffic accidents. METHODS In this double-blinded, 3-way crossover trial, 17 healthy males received acute doses of 10 mg paroxetine, 25 mg amitriptyline, and placebo. The subjects were administered three driving tasks--road tracking, car following, and harsh braking--performed using a driving simulator and three cognitive tasks--Wisconsin Card Sorting Test, Continuous Performance Test, and N-back test at baseline and at 1 h and 4 h post-dosing. The Stanford Sleepiness Scale scores were also assessed. RESULTS At 4 h post-dosing, amitriptyline significantly impaired road-tracking and car-following performance, reduced driver vigilance, and caused subjective somnolence. Paroxetine impaired neither driving performance nor cognitive function. CONCLUSIONS Acute doses of amitriptyline significantly impaired driving performance in the context of driving on crowded urban roads at relatively low speeds. This setting is important with respect to skills necessary for daily driving and may be difficult to measure in actual driving tests. This simulator-based study replicated the results of previous studies and could be considered complementary to them. This method may enable easy and safe screening of the driving hazard potential of drugs.