The difficult issue of assessing fitness to drive has sat uncomfortably with many doctors, who on the one hand have a clear duty of care to protect their patients and the general public, and for the other part want to preserve the special relationship of trust and they share, and to allow people to retain the independence that the ability to drive allows. In Australia & New Zealand the relevant parameters are laid out in the document Assessing Fitness to Drive: a comprehensive compendium that nevertheless is open to interpretation and the section dealing with the effects of medications is at times nebulous.

Recent data published in the New England Journal of Medicine casts a new light on the issue. Canadian researchers identified a patients who received a medical warning from a physician who judged them to be potentially unfit to drive and then analyzed emergency department visits for road crashes during a baseline interval before the warning and a subsequent interval after the warning. During a  3-year baseline interval, there were 1430 road crashes in which the patient was a driver and presented to the emergency department, as compared with 273 road crashes during the 1-year subsequent interval – a reduction of approximately 45% in the annual rate of crashes per 1000 patients after the warning (4.76 vs. 2.73, P<0.001). There was no change crashes in which patients were pedestrians or passengers. Medical warnings were associated with a decrease in return visits to the doctor issuing the warning. These findings point to a fundamental conflict – in identifying these people for whom driving was risky, the chance of involvement (as a driver) in a traffic accident was not reduced, but the prevalence of depression appeared to be increased amongst the recipients of the warnings. The question is – should there have been more than a warning? If these patients were thought to be unfit to drive, would an action to revoke their licence to do so have resulted in reduced morbidity and mortality for these and other road users? It would appear that the issue is far from settled.