A retrospective study of drugged driving in Norway

The National Institute of Forensic Toxicology, Oslo, receives blood and urine samples from all Norwegian drivers apprehended on suspicion of driving under the influence of alcohol or drugs. In 1983 we received samples from 1446 drug-suspected drivers, out of which 445 underwent toxicological analysis. The drugs found most frequently were tetrahydrocannabinol (THC) (n = 199), diazepam (n = 166) and amphetamine (n = 102). A cautious interpretation of the data indicate that about 200 of the 445 subjects selected for toxicological analysis drove under severe influence of drugs. Because of the high percentage of submitted cases not analysed for drugs, this figure represents a minimum estimate. Compared with the results from 1978, we found a several-fold increase in detections of THC and amphetamine in 1983. The number of diazepam detections did not increase in a similar way, but we estimated that the diazepam detections would have increased 3-fold if we had analysed as frequent for this drug in 1983 as in 1978.