title: Prevalence and co-occurrence of addictive behaviors among former alternative high school youth: A longitudinal follow-up study.
abstract: OBJECTIVE
  Recent work has studied addictions using a matrix measure, which taps multiple addictions through single responses for each type. This is the first longitudinal study using a matrix measure.
  
  
  METHODS
  We investigated the use of this approach among former alternative high school youth (average age = 19.8 years at baseline; longitudinal n = 538) at risk for addictions. Lifetime and last 30-day prevalence of one or more of 11 addictions reviewed in other work was the primary focus (i.e., cigarettes, alcohol, hard drugs, shopping, gambling, Internet, love, sex, eating, work, and exercise). These were examined at two time-points one year apart. Latent class and latent transition analyses (LCA and LTA) were conducted in Mplus.
  
  
  RESULTS
  Prevalence rates were stable across the two time-points. As in the cross-sectional baseline analysis, the 2-class model (addiction class, non-addiction class) fit the data better at follow-up than models with more classes. Item-response or conditional probabilities for each addiction type did not differ between time-points. As a result, the LTA model utilized constrained the conditional probabilities to be equal across the two time-points. In the addiction class, larger conditional probabilities (i.e., 0.40-0.49) were found for love, sex, exercise, and work addictions; medium conditional probabilities (i.e., 0.17-0.27) were found for cigarette, alcohol, other drugs, eating, Internet and shopping addiction; and a small conditional probability (0.06) was found for gambling.
  
  
  CONCLUSIONS
  Persons in an addiction class tend to remain in this addiction class over a one-year period.
authors.affiliation: Institute for Health Promotion and Disease Prevention Research, University of Southern California Keck School of Medicine , Alhambra, CA , USA.
authors.forename: Steve
authors.initials: S
authors.lastname: Sussman
authors.affiliation: Cancer Prevention and Control Program, University of Hawaii Cancer Center , Honolulu, HI , USA.
authors.forename: Pallav
authors.initials: P
authors.lastname: Pokhrel
authors.affiliation: Institute for Health Promotion and Disease Prevention Research, University of Southern California Keck School of Medicine , Alhambra, CA , USA.
authors.forename: Ping
authors.initials: P
authors.lastname: Sun
authors.affiliation: Institute for Health Promotion and Disease Prevention Research, University of Southern California Keck School of Medicine , Alhambra, CA , USA.
authors.forename: Louise A
authors.initials: LA
authors.lastname: Rohrbach
authors.affiliation: Institute for Health Promotion and Disease Prevention Research, University of Southern California Keck School of Medicine , Alhambra, CA , USA.
authors.forename: Donna
authors.initials: D
authors.lastname: Spruijt-Metz
mesh_terms: D016739:Behavior, Addictive / Q000453:epidemiology* / Q000523:psychology*; D002140:California / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D015233:Models, Statistical; D015995:Prevalence; D012307:Risk Factors; D055815:Young Adult
keywords: co-occurrence; latent transitions analysis; multiple addictions; prevalence; stability of class membership