"Turning on" other persons to drugs

Data obtained in a recent national survey are examined to test two hypotheses about drug transmission. The hypothesis that transmission of drug use to others is most likely to occur within a short period of time after initial use is supported. For each drug or drug class, at least one-half of the users who transmitted drug use to others did so within a span of 2 years after they began to use the drug. One-fourth of the marijuana users "turned on" others. Marijuana users are more likely to transmit their drug use than are users of other illicit drugs, but most drug users never "turn on" others. The hypothesis that drug transmission occurs only within a short period of time after onset of use is rejected. Among marijuana users who "turned on" others, 29% of them did so 5 or more years after they first used marijuana.