Objectives: The objective of this study was to examine the frequency of psychoactive drugs and alcohol in
drivers under suspicion of driving under the influence of drugs and alcohol in 2015 and 2016 in the eastern
part of Denmark. The trends in the number of traffic cases sent for drug analysis since 2000 and alcohol
analysis since 2011 are also discussed.
Methods: Blood samples from drivers suspected of being under the influence of alcohol and/or medication
and/or illicit drugs in 2015 and 2016 were investigated as requested by the police. The blood samples
were screened for alcohol and/or tetrahydrocannabinol (THC) alone, for other drugs (covering all drugs,
except THC, listed in the Danish list of narcotic drugs), or for THC and other drugs. Age and gender were
also recorded. The number of drug traffic cases since 2000 and the number of alcohol cases since 2011 were
extracted from our Laboratory Information Management System (LIMS).
Results: In total, 11,493 traffic caseswere investigated. Alcohol and/or drugs exceeded the legal limit in 9,657
(84%) cases. Men constituted 95% of the drivers investigated for drugs and 88% of the alcohol cases. The
drivers investigated for drugs consisted primarily of young men, whereas drivers investigated for alcohol
were older.
The frequency was higher for positive alcohol cases above the legal limit (87%) than for drug cases (76%)
above the fixed concentration limit. THC (67–69%) was the most frequently detected drug above the legal
limit, followed by cocaine (27–28.5%), amphetamine (17%), and clonazepam (6–7%) in both years.Morphine
(5.4%), included among the 5 most frequent drugs in 2015, was replaced by methadone (4.6%) in 2016. Few
new psychoactive drugs (NPS) were detected.
The number of traffic cases sent for drug analysis has increased more than 30-fold since 2000–2006, and the
number of traffic cases submitted in 2016 for drug analysis was higher than the number for alcohol analysis;
the latter has decreased since 2011.
Conclusion: Overall, alcohol was the most frequent compound detected above the legal limit in both years,
followed by the well-known illicit drugs THC, cocaine, and amphetamine. NPS were seldom seen. One consequence
of the increased focus on drugs in traffic has been an immense increase in drug traffic cases sent
for analysis since 2006 in the eastern part of Denmark. Although this survey revealed onlyminimal changes
compared to earlier investigations, surveys like this are invaluable for monitoring abuse patterns and trends
in drugged and drunken driving.