title: Progression to regular heroin use: examination of patterns, predictors, and consequences.
abstract: BACKGROUND
  The present study retrospectively evaluated the chronology and predictors of substance use progression in current heroin-using individuals.
  
  
  METHODS
  Out-of-treatment heroin users (urinalysis-verified; N=562) were screened for laboratory-based research studies using questionnaires and urinalysis. Comprehensive substance use histories were collected. Between- and within-substance use progression was analyzed using stepwise linear regression models.
  
  
  RESULTS
  The strongest predictor of onset of regular heroin use was age at initial heroin use, accounting for 71.8% of variance. The strongest between-substance predictors of regular heroin use were ages at regular alcohol and tobacco use, accounting for 8.1% of variance. Earlier onset of regular heroin use (≤20 years) vs. older onset (≥30 years) was associated with a more rapid progression from initial to regular use, longer duration of heroin use, more lifetime use-related negative consequences, and greater likelihood of injecting heroin. The majority of participants (79.7%) reported substance use progression consistent with the gateway hypothesis. Gateway-inconsistent individuals were more likely to be African-American and to report younger age at initial use, longer duration of heroin use, and more frequent past-month heroin use.
  
  
  CONCLUSIONS
  Our findings demonstrate the predictive validity and clinical relevance of evaluating substance use chronology and the gateway hypothesis pattern of progression.
authors.affiliation: Department of Psychiatry and Behavioral Neurosciences, School of Medicine, Wayne State University, Detroit, MI 48201, USA; Translational Neuroscience Program, Wayne State University, Detroit, MI 48201, USA.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Woodcock
authors.affiliation: Department of Psychiatry and Behavioral Neurosciences, School of Medicine, Wayne State University, Detroit, MI 48201, USA; Translational Neuroscience Program, Wayne State University, Detroit, MI 48201, USA.
authors.forename: Leslie H
authors.initials: LH
authors.lastname: Lundahl
authors.affiliation: Department of Psychiatry and Behavioral Neurosciences, School of Medicine, Wayne State University, Detroit, MI 48201, USA.
authors.forename: Jonathan J K
authors.initials: JJ
authors.lastname: Stoltman
authors.affiliation: Department of Psychiatry and Behavioral Neurosciences, School of Medicine, Wayne State University, Detroit, MI 48201, USA; Translational Neuroscience Program, Wayne State University, Detroit, MI 48201, USA; Department of Pharmacy Practice, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA. Electronic address: mgreen@med.wayne.edu.
authors.forename: Mark K
authors.initials: MK
authors.lastname: Greenwald
mesh_terms: D000293:Adolescent; D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data; D017668:Age of Onset; D000428:Alcohol Drinking / Q000453:epidemiology*; D019970:Cocaine-Related Disorders / Q000453:epidemiology*; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D006556:Heroin Dependence / Q000453:epidemiology* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008385:Marijuana Smoking / Q000453:epidemiology*; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D012907:Smoking / Q000453:epidemiology*; D013997:Time Factors; D044465:White People / Q000706:statistics & numerical data; D055815:Young Adult
keywords: Gateway hypothesis; Heroin use disorder; Opioid; Substance use progression