Patterns and predictors of simultaneous and concurrent use of alcohol, tobacco, marijuana, and hallucinogens in first-year college students.

Polydrug use produces important health and safety risks. Little research has examined whether multiple drugs are used simultaneously (at the same time or in close temporal sequence). Instead, researchers have assessed concurrent polydrug use (the use of multiple drugs within a given time period such as years or months). The research here examined patterns and predictors of both simultaneous and concurrent polydrug use in 575 first-year college students. Both concurrent and simultaneous polydrug use were common for alcohol, tobacco, and marijuana. The percentage of concurrent polydrug users who were also simultaneous polydrug users ranged from 82% to 93% across subgroups defined by gender and the use of a single drug. Male gender, high levels of sensation seeking, and frequent alcohol use predicted single-drug versus polydrug use status as well as simultaneous polydrug use. Patterns and predictors of simultaneous and concurrent polydrug use should be addressed in prevention research and preventative interventions.