Hoe waarheidsgetrouw zijn verklaringen over middelengebruik in het rijgeschiktheidsonderzoek?

How truthful are statements about substance use in the fitness to drive examination? In Belgium, the court can order a fitness to drive examination on indication. One is not fit to drive if there has been excessive alcohol and/or drug use in the past 6 months. Chronic excessive alcohol use corresponds to an average consumption of ≥ 6 units per day or ≥ 42 units per week over several months. Toxicologically, 30 pg/mg ethylglucuronide (direct alcohol marker) in scalp hair strongly suggests this. For drugs, it is sufficient to demonstrate this substance in one of the samples. The anamnesis and toxicology were compared with a McNemar test. The sensitivity, specificity and positive/negative predictive value of the anamnesis as a diagnostic test were calculated. People are more likely to be unfit to drive based on the toxicological analysis than based on the anamnesis (respectively 60% versus 40%). The greatest discrepancy is seen regarding alcohol consumption. In addition, toxicologically more cases of drug use were detected. This study shows that statements regarding alcohol and drug use within the fitness to drive examination are not reliable.