Drug findings in 'Driving Under the Influence of Drugs' cases: a problem of illicit drug use.

Drug findings in 137 drug positive cases of Driving Under the Influence of Drugs (DUID) occurring in St. Louis, Missouri, U.S.A. from June 1983 through May 1986 are presented. Thirty-two different drugs were detected. A single agent was detected in only 34% (47/137) of cases. The most frequently encountered drugs, expressed as percent of positive cases, were: phencyclidine, 47%; marijuana, 47%; benzodiazepines, 22%; barbiturates, 15%; opiates, 11%; and cocaine, 9%. Most multiple drug cases involved popular illicit drug mixtures, such as cocaine and morphine (speedballs) or phencyclidine on marijuana (whack). All the drivers in this survey had displayed inappropriate or impaired operation of a motor vehicle to the extent that a law enforcement officer had stopped and charged them for DUID. In at least 81% of the drug positive cases, persons impaired in the operation of a motor vehicle from a drug or drugs other than alcohol, were impaired not as the result of side effects of therapeutic drug use, but as the result of deliberate self intoxication with illicit or controlled substances.