Referrals for psychiatric examination of driving ability - a comparison of illicit drugs and alcohol

Introduction: In Austria vehicle drivers impaired by drugs or alcohol have to undergo a psychiatric examination. Drivers who are not accused for impaired driving have to undergo a psychiatric examination too if they are suspected to be alcohol - or drug addicted. Public health officers decide on the need to refer to psychiatric examination. Methods: 145 drivers suspected to be alcohol - or drug addicted had been referred to the author for psychiatric examination between January 2002 and August 2005. The records of these patients were examined for the following criteria: the reason for psychiatric examination (accident, impaired driving, others), the pattern of substance using, abnormal laboratory testing (urine test, lever function test, carbohydrate-deficient transferrin). Alcohol consumers/abusers and drug consumers/abusers were compared. Results: Alcohol consumers/abusers (n=75) had regularly been penalized for impaired driving (86.7%) or for accidents (26.7%) and 88% had consumed alcohol regularly (once a week or more). Only few drug consumers/abusers (n=86, mostly cannabis) had been penalized for impaired driving (7%), none had an accident and 69.8% had consumed illicit drugs once a week or more. In the vast majority of these cases other reasons than impaired driving caused authorities' action. Laboratory tests were abnormal in 37.3% of alcohol consumers/abusers and in 4.7% of drug consumers/abusers indicating ongoing substance use. Conclusion: Although the increasing use of cannabis and amphetamines is a problem, our data indicate that still alcohol is by far the most dangerous psychotropic substance for traffic safety. Authorities seem to overestimate the risk for road safety associated with illicit drug use.