title: Concurrent and simultaneous polydrug use: latent class analysis of an Australian nationally representative sample of young adults.
abstract: BACKGROUND
  Alcohol use and illicit drug use peak during young adulthood (around 18-29 years of age), but comparatively little is known about polydrug use in nationally representative samples of young adults. Drawing on a nationally representative cross-sectional survey (Australian National Drug Strategy Household Survey), this study examines polydrug use patterns and associated psychosocial risk factors among young adults (n = 3,333; age 19-29).
  
  
  METHODS
  The use of a broad range of licit and illicit drugs were examined, including alcohol, tobacco, cannabis, cocaine, hallucinogens, ecstasy, ketamine, GHB, inhalants, steroids, barbiturates, meth/amphetamines, heroin, methadone/buprenorphine, other opiates, painkillers, and tranquilizers/sleeping pills. Latent class analysis was employed to identify patterns of polydrug use.
  
  
  RESULTS
  Polydrug use in this sample was best described using a 5-class solution. The majority of young adults predominantly used alcohol only (52.3%), alcohol and tobacco (34.18%). The other classes were cannabis, ecstasy, and licit drug use (9.4%), cannabis, amphetamine derivative, and licit drug use (2.8%), and sedative and alcohol use (1.3%). Young adult males with low education and/or high income were most at risk of polydrug use.
  
  
  CONCLUSIONS
  Almost half of young adults reported polydrug use, highlighting the importance of post-high school screening for key risk factors and polydrug use profiles, and the delivery of early intervention strategies targeting illicit drugs.
authors.affiliation: Faculty of Health Sciences, Centre for Youth Substance Abuse Research, The University of Queensland , Brisbane, QLD , Australia.
authors.forename: Lake-Hui
authors.initials: LH
authors.lastname: Quek
authors.affiliation: Faculty of Health Sciences, Centre for Youth Substance Abuse Research, The University of Queensland , Brisbane, QLD , Australia.
authors.forename: Gary C K
authors.initials: GC
authors.lastname: Chan
authors.affiliation: Faculty of Health Sciences, Centre for Youth Substance Abuse Research, The University of Queensland , Brisbane, QLD , Australia.
authors.forename: Angela
authors.initials: A
authors.lastname: White
authors.affiliation: Faculty of Health Sciences, Centre for Youth Substance Abuse Research, The University of Queensland , Brisbane, QLD , Australia ; School of Medicine, The University of Queensland , Brisbane, QLD , Australia.
authors.forename: Jason P
authors.initials: JP
authors.lastname: Connor
authors.affiliation: Faculty of Health Sciences, Centre for Youth Substance Abuse Research, The University of Queensland , Brisbane, QLD , Australia ; Faculty of Health Sciences, School of Population Health, The University of Queensland , Brisbane, QLD , Australia.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Baker
authors.affiliation: Faculty of Health Sciences, Centre for Youth Substance Abuse Research, The University of Queensland , Brisbane, QLD , Australia.
authors.forename: John B
authors.initials: JB
authors.lastname: Saunders
authors.affiliation: Faculty of Health Sciences, Centre for Youth Substance Abuse Research, The University of Queensland , Brisbane, QLD , Australia.
authors.forename: Adrian B
authors.initials: AB
authors.lastname: Kelly
keywords: cluster; latent class analysis; polydrug use; risk and protective factors; simultaneous; young adults