In the Netherlands, young men and older adults (70+) are important groups at risk of driving under the influence of drugs and medicines respectively.
Drugs
The DRUID study found that, throughout Europe, the risk of driving under the influence of drugs (both of a single drug or of combined drugs) was highest among young men [13]. The younger the driver, the more often cannabis was used. Male drivers aged 25 to 34 also used cocaine and amphetamines quite often [37]. Heroin was mostly used by male drivers aged 35 to 49 [37].
Not much is known about the relationship between drug dependency and road crashes [38]. Therefore, we do not know to what extent drug addicts are a risk group for road safety.
Medicines
Older adults use three times as many medicines as the average Dutch citizen (source: Stichting Farmaceutische kengetallen). How many of these are impairing medicines and to what extent users drive while under their influence is, however, unknown.
Older adults (70+) often have multiple ailments and take several medicines to remedy them (polypharmacy) [19]. Use of multiple medicines may, especially for older adults, result in unwanted side effects. When aging, the body composition changes and liver and kidney functions are often impaired, which results in slower or less thorough elimination of medicine effects. These bodily changes and the possible interaction of multiple medicines may result in unwanted side effects, among which impairment of fitness to drive [39]. Increased crash risks on account of medicine combinations have been proven in research [20].
