title: Patterns of concurrent substance use among adolescent nonmedical ADHD stimulant users.
abstract: OBJECTIVE
  There are growing concerns about nonmedical use of ADHD stimulants among adolescents; yet, little is known whether there exist heterogeneous subgroups among adolescents with nonmedical ADHD stimulant use according to their concurrent substance use.
  
  
  METHODS
  We used latent class analysis (LCA) to examine patterns of past-year problematic substance use (meeting any criteria for abuse or dependence) in a sample of 2203 adolescent participants from the National Surveys on Drug Use and Health 2006-2011 who reported past-year nonmedical use of ADHD stimulants. Multivariable latent regression was used to assess the association of socio-demographic characteristics, mental health and behavioral problems with the latent classes.
  
  
  RESULTS
  The model fit indices favored a four-class model, including a large class with frequent concurrent use of alcohol and marijuana (Alcohol/marijuana class; 41.2%), a second large class with infrequent use of other substances (Low substance class, 36.3%), a third class characterized by more frequent misuse of prescription drugs as well as other substances (Prescription drug+class; 14.8%), and finally a class characterized by problematic use of multiple substances (Multiple substance class; 7.7%). Compared with individuals in Low substance class, those in the other three classes were all more likely to report mental health problems, deviant behaviors and substance abuse service use.
  
  
  CONCLUSIONS
  Adolescent nonmedical ADHD stimulants users are a heterogeneous group with distinct classes with regard to concurrent substance use, mental health and behavioral problems. The findings have implications for planning of tailored prevention and treatment programs to curb stimulant use for this age group.
authors.affiliation: Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, 624 N. Broadway, 7th Floor, Baltimore, MD 21205, United States; Taipei City Psychiatric Center, Taipei City Hospital, No. 309, Songde Rd., Xinyi Dist., Taipei City, Taiwan. Electronic address: lianyu0928@gmail.com.
authors.forename: Lian-Yu
authors.initials: LY
authors.lastname: Chen
authors.affiliation: Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, 624 N. Broadway, 7th Floor, Baltimore, MD 21205, United States; Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD 21224, United States; Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street W6035, Baltimore, MD 21205, United States.
authors.forename: Rosa M
authors.initials: RM
authors.lastname: Crum
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD 21224, United States.
authors.forename: Eric C
authors.initials: EC
authors.lastname: Strain
authors.affiliation: Department of Epidemiology, Mailman School of Public Health, Columbia University, 722 West 168th Street, Rm. 509, New York, NY 10032, United States.
authors.forename: Silvia S
authors.initials: SS
authors.lastname: Martins
authors.affiliation: Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, 624 N. Broadway, 7th Floor, Baltimore, MD 21205, United States; Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD 21224, United States.
authors.forename: Ramin
authors.initials: R
authors.lastname: Mojtabai
mesh_terms: D000293:Adolescent; D000662:Amphetamines; D000701:Analgesics, Opioid; D000697:Central Nervous System Stimulants; D002648:Child; D019970:Cocaine-Related Disorders / Q000453:epidemiology; D003913:Dextroamphetamine; D005260:Female; D006213:Hallucinogens; D006556:Heroin Dependence / Q000453:epidemiology; D006801:Humans; D006993:Hypnotics and Sedatives; D058545:Inhalant Abuse / Q000453:epidemiology; D000069478:Lisdexamfetamine Dimesylate; D008297:Male; D008385:Marijuana Smoking / Q000453:epidemiology*; D008774:Methylphenidate; D015999:Multivariate Analysis; D010389:Pemoline; D063487:Prescription Drug Misuse / Q000706:statistics & numerical data*; D012044:Regression Analysis; D019966:Substance-Related Disorders / Q000453:epidemiology*; D000066608:Underage Drinking / Q000706:statistics & numerical data*; D014481:United States / Q000453:epidemiology
chemical_list: C090411:Adderall; D000662:Amphetamines; D000701:Analgesics, Opioid; D000697:Central Nervous System Stimulants; D006213:Hallucinogens; D006993:Hypnotics and Sedatives; D008774:Methylphenidate; D010389:Pemoline; D000069478:Lisdexamfetamine Dimesylate; D003913:Dextroamphetamine
keywords: ADHD stimulants; Deviant behaviors; Latent class analysis; Substance abuse