As part of a larger interview study previously reported, 100 regular marihuana users, and their use of other drugs have been analyzed. Forty-eight subjects were found to have used two or less other drugs, and 52 were found to have used more than two other drugs (mean 7.5).
Early antecedent and concomitant behavioral events significantly associated with "polydrug" use were sought to describe a possible syndrome. Childhood discipline contacts, truancy and dropout, age of first illicit drug use, first illicit drug not being marihuana, poor high school socialization, inordinate parental conflicts, poor adolescent adjustment, antisocial behavior, police contacts, homosexual experiences, and self-defeating behavior in adolescence were found to predict later polydrug use from among this population. The methodologic pitfalls of distinguishing antecedents from concomitants are discussed.
Halikas JA, Rimmer JD. Predictors of Multiple Drug Abuse. Arch Gen Psychiatry. 1974;31(3):414-418. doi:10.1001/archpsyc.1974.01760150116017