Driving under the influence of drugs is a growing problem as the number of apprehended drivers in Norway has increased 2.5 times since 1990. At least two drugs are usually detected. The majority of offenders have been arrested earlier. This paper gives an overview of studies of impaired drivers.
Material and methods: The re-arrest rate among 1102 drivers under the influence of drugs was followed for 7.5 years and compared with a group of 850 drivers under the influence of alcohol. Another study included 874 drivers with benzodiazepine detections followed retrospectively for 11 years. Earlier arrests and drugs detected first time were recorded. The third study recorded deaths among drugged (n = 918) and drunken (n = 2531) drivers for 7.5 years, compared with same age group in the general population.
Results: 57% of drugged and 28% of drunken drivers were re-arrested. More the 60% of drivers with benzodiazepine detections had been arrested earlier. Alcohol was most the commonly detected substance at first arrest. The standardised mortality ratio for male drugged drivers was 18.1 (14.9-21.8), for drunken drivers 3.7 (2.9-4.7).
Interpretation: Our results show that drugged drivers represent risk groups with multi-drug use, frequent re-arrests and early death. Other efforts combined with fines, prison and withdrawal of driving licence should be considered. Some countries have follow-up programmes that include control of drug use by urine testing before a re-issue of the driving licence is considered.