Toxicological findings in suspected drug-impaired drivers in Norway — Trends during 1990–2015

Abstract

This study describes trends in drug use among drivers suspected of driving under the influence of drugs, apprehended by the police in Norway during 1990-2015. Chromatographically determined toxicological findings in blood samples were retrospectively investigated. Drug findings above defined cut-off concentrations were considered positive; hence making the annual prevalence comparable during the 26 years studied. Blood samples from 112,348 drivers were included, of which 63% were positive for drugs; 43% had combined drug with alcohol or other drugs. In total, 87% of the drug-positive drivers were men, and a higher proportion of them were positive for illicit drugs compared to the women. Benzodiazepines and related drugs were found in 57% of the drug-positive drivers, stimulants in 51%, cannabis (tetrahydrocannabinol, THC) in 34%, and opioids in 18%. The types of benzodiazepines and opioids changed over time. The age distribution also changed; the proportion of drug-positive drivers above 40 years of age increased for all drug classes. The annual number of suspected drug-impaired drivers increased by 122% from 1990 to 1999, and by 54% from 2000 to 2015; the annual number of drug-positive samples increased by 260% from 1990 to 1999, and by 60% from 2000 to 2015. During 2000-2015, an increasing prevalence of amphetamines was found among suspected drug-impaired drivers above age 30; the highest rate of increase was observed among those at or above age 40. In the same period, the prevalence of benzodiazepines and related drugs decreased among all age groups, whereas the prevalence of THC increased; the highest prevalence and rate of increase were among suspected drug-impaired drivers under the age of 30. The results from this study indicate a slight change in the types of drugs used by drivers in Norway.

The Effect of Lowering the Legal Drink‐Drive Limit on the Toxicological Findings in Driver Fatalities: A Comparison of Two Jurisdictions,

“…In addition, many of the deceased drivers in this study were positive for multiple substances, creating difficulty in determining whether or not certain drugs contributed to any impairment at the time of the MVC . We were also unable to assess the contribution of drug–drug interactions in polydrug use cases , and there is the possibility that some drugs might have degraded in postmortem blood between sampling and testing .…”

“…The first country to introduce a legal per se BAC limit was Norway, in 1936 . The limit was set at 50 mg/100 mL and has since been reduced to 20 mg/100 mL . Sweden reduced their legal BAC limit from 80 to 50 mg/100 mL in 1957 , and this has been followed by the same reduction in numerous other countries .…”

The implementation of per-se limits for driving under the influence of benzodiazepines and related drugs: No increased risk for arrest during therapeutic use in Norway

“…During the study period, all blood samples were analyzed using standard protocols and analytical methods accredited by Norwegian Accreditation (Lillestrøm, Norway). This included primary screening for all compounds on the assigned legislative limit list (BZDs, z-hypnotics, opioids, stimulants, and certain hallucinogens) as well as other commonly used drugs (e.g., pregabalin and tramadol) using ultra high-performance liquid chromatography-mass spectrometry (UHPLC-MS); drug detection was confirmed and quantified by alternative methods (Valen et al 2017). A safety margin of 34% was deducted from the quantified concentrations for all BZDs and z-drugs included in this study (Kristoffersen et al 2016).…”

“…The number of samples with at least one drug above the per se limit corresponding to a BAC of 0.20 g/kg increased by 17%, while the number of expert witness statements was reduced by half (Vindenes et al 2014). The most frequently detected compounds in blood samples from suspected DUI offenders besides alcohol during the period 1990-2015 were benzodiazepines (BZDs), tetrahydrocannabinol (THC), amphetamines, and opioids (Valen et al 2017); multidrug detections were common.…”

Driving under the influence of drugs

“…In the same period, the prevalence of benzodiazepines and related drugs decreased among all age groups, whereas the prevalence of THC increased. The highest prevalence and rate of increase were among suspected drug‐impaired drivers under the age of 30 (Valen, Bogstrand, Vindenes, & Gjerde, ).…”