The effects of escitalopram 10 to 20 mg/day and mirtazapine 30 to 45 mg/day on actual
driving and psychomotor performance of 18 healthy subjects were determined in a randomized,
double-blind, placebo-controlled, multiple-dose, 3-way crossover trial.
Each treatment period lasted for 15 days and was separated from the next period by
a washout period of at least 13 days. Subjects received an evening dose of escitalopram
10 mg, mirtazapine 30 mg, or placebo from days 1 to 7 and an evening dose of escitalopram
20 mg, mirtazapine 45 mg, or placebo from days 8 to 15. On days 2, 9, and 16, reflecting
acute period, dose increase, and steady state, respectively, the Road Tracking Test
was performed. The main parameter was standard deviation of lateral position. Psychomotor
performance was also assessed on days 2, 9, and 16 by laboratory computer tasks. Subjective
sleep quality was measured with the Groninger Sleep Quality Scale, and mood was measured
by visual analogue scales.
Treatment differences were apparent during the acute treatment period, in which subjects
treated with mirtazapine 30 mg performed less well on the driving test as compared
to placebo. The Divided Attention Task results also revealed a significant increase
in tracking error after a single dose of mirtazapine 30 mg as compared to placebo.
Mirtazapine decreased feelings of alertness and contentedness. Mirtazapine did not
affect performance on days 9 and 16 of treatment. Escitalopram did not affect driving,
psychomotor performance, or subjective mood throughout treatment.
Driving performance, as well as psychomotor functioning, was not affected by escitalopram
treatment in healthy subjects. Driving performance was significantly impaired after
ingestion of mirtazapine 30 mg during the acute treatment period.