The effects of chronic lithium treatment on psychomotor performance related to driving.

A group of 16 psychiatric out-patients in remission, who had been taking lithium carbonate as their sole medication for at least three months, were compared with a control group of 22 healthy volunteers. On a computerised driving simulator which produced measures of reaction time, tracking ability and mistakes made, the patient group had a significantly slower reaction time. Patients should be warned therefore that lithium may affect their ability to drive or operate machinery and that psychomotor impairment and sedation are not synonymous.