What non-alcohol drugs are used by drinking drivers in Sweden? Toxicological results from ten years of forensic blood samples.

Methods: Using a forensic toxicology database (TOXBASE), the toxicological results from 10 years of forensic blood samples from people arrested for driving under the influence of alcohol and/or other drugs were reviewed.

Results: Alcohol was the only drug identified in blood in N=35,704 cases at a median blood-alcohol concentration (BAC) of 1.63 mg/g. The mean age (±SD) of these offenders was 40±15years and 89% were male. The median BAC was lower (1.30 mg/g) in drivers who had consumed alcohol and used a prescription drug before driving (N=1,251). The mean age of this group of traffic offenders was 38±13years and 85% were male. Both the median BAC (0.97 mg/g) and the mean age were lowest (36±11years, 92% male) in N=3,153 drivers who had consumed alcohol and used illicit drugs before driving. Cannabis, amphetamine, cocaine and morphine (metabolite of heroin) were the commonest illicit drugs identified in blood samples. Sedative-hypnotics (benzodiazepines) were the major prescription drugs co-ingested with alcohol. Poly-drug use was a common finding in these traffic delinquents, although individuals who only drank alcohol had a higher median BAC and were also several years older than drinking drivers combining alcohol with other drugs before driving.

Conclusions: Zero-tolerance legislation did not deter hard-core offenders. In future there should be more focus on treatment for alcohol and substance abuse disorder rather than conventional punishments for this type of traffic crime.