title: Patterns of simultaneous polysubstance use in drug using university students.
abstract: Simultaneous polysubstance use (SPU) is a common phenomenon, yet little is known about how various substances are used with one another. In the present study 149 drug-using university students completed structured interviews about their use of various substances. For each substance ever used, participants provided details about the type, order and amount of all substances co-administered during its most recent administration. Alcohol, tobacco and cannabis were frequently co-administered with each other and with all other substances. Chi-squared tests revealed that when alcohol was used in combination with any of cannabis, psilocybin, MDMA, cocaine, amphetamine, methylphenidate (ps < 0.01) or LSD (p < 0.05) its initial use preceded the administration of the other substance. Paired samples t-tests revealed that when alcohol was used with cocaine (p < 0.01) or methylphenidate (p < 0.05) it was ingested in greater quantities than when used in their absence. Patterns of cannabis use were not systematically related to other substances administered. Finally, using one-sample t-tests, tobacco use was demonstrated to be increased relative to 'sober' smoking rates when used with alcohol, cannabis, psilocybin, MDMA, cocaine, amphetamine (ps < 0.001), LSD (p < 0.01) or methylphenidate (p < 0.05). Results suggest that many substances are routinely used in a SPU context and that the pattern in which a substance is used may be related to other substances co-administered.
authors.affiliation: Department of Psychology, McGill University, Montreal, Quebec, Canada.
authors.forename: Sean P
authors.initials: SP
authors.lastname: Barrett
authors.forename: Christine
authors.initials: C
authors.lastname: Darredeau
authors.forename: Robert O
authors.initials: RO
authors.lastname: Pihl
mesh_terms: D000293:Adolescent; D000328:Adult; D000437:Alcoholism / Q000453:epidemiology; D003042:Cocaine / Q000008:administration & dosage; D000431:Ethanol / Q000008:administration & dosage; D005260:Female; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000453:epidemiology; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000008:administration & dosage; D012907:Smoking / Q000453:epidemiology; D013334:Students; D019966:Substance-Related Disorders / Q000453:epidemiology*; D014495:Universities
chemical_list: D000431:Ethanol; D003042:Cocaine; D018817:N-Methyl-3,4-methylenedioxyamphetamine