Objectives: Many drugs, both illicit or for medication, are known to influence driving abilities and increase risks of accidents.
We explored the prevalence of psychoactive substances in a random sample of drivers in Switzerland.
Methods: Saliva samples from 1078 random drivers were collected at 24 different locations in Western Switzerland
from October 2006 to April 2008 for complete toxicological analysis using liquid chromatography/tandem
mass spectrometry.
Results: Provisional results are available for 437 drivers. 6.2% (CI95% 4.1 to 8.9) were under the influence of illicit
drugs and 8.7% under psychoactive medication (CI95% 6.2 to 11.7). 37 drivers (8.5%) were under the influence
of alcohol of which 14 (3.2%) were above 0.8 mg/L. 21 drivers (4.8%) were under the combined influence
of more than one psychoactive substance; however only 4 drivers (0.9%) were under both the
influence of medication and alcohol. Looking more specifically at illicit substances, 22 (5.0%) were positive
to cocaine, 5 (1.1%) to cannabis, and 2 (0.5%) to amphetamines ; for psychoactive medication, 17
(3.9%) were positive to benzodiazepines, 16 (3.7%) to antidepressors, 7 (1.6%) to opiates, 7 (1.6%) to
neuroleptics, and 3 (0.7%) to other substances influencing driving abilities. 17/21 drivers did not self-report
their consumption of drugs whereas only 9/35 failed mentioning their medication. Men drivers were
3.2 times (CI95% 1.1 to 9.5) more likely to be under the influence of illicit drugs than women. Full results
will be reported when laboratory data will be available in April.
Conclusions: Driving under the influence of psychoactive substances is common. In Western Switzerland, prevention
messages could focus on men, driving under medication or cocaine.