title: The relevance of age at first alcohol and nicotine use for initiation of cannabis use and progression to cannabis use disorders.
abstract: BACKGROUND
  A younger age at onset of use of a specific substance is a well-documented risk-factor for a substance use disorder (SUD) related to that specific substance. However, the cross-substance relationship between a younger age at onset of alcohol use (AU) and nicotine use (NU) and the risk of cannabis use disorders (CUD) in adolescence and early adulthood remains unclear.
  
  
  OBJECTIVE
  To identify the sequence of and latency between initial AU/NU and initial cannabis use (CU). To investigate whether younger age at AU- and NU-onset is associated with any and earlier CU-onset and a higher risk of transition from first CU to CUD, taking into account externalizing disorders (ED) and parental substance use disorders as putative influential factors.
  
  
  METHODS
  Prospective-longitudinal community study with N=3021 subjects (baseline age 14-24) and up to four assessment waves over up to ten years with additional direct parental and family history information. Substance use and CUD were assessed with the DSM-IV/M-CIDI.
  
  
  RESULTS
  Most subjects with CU reported AU (99%) and NU (94%). Among users of both substances, 93% reported AU prior to CU (87% for NU). After adjustment for ED and parental substance use disorders younger age at AU-onset was associated with any CU. Younger age at NU-onset was associated with earlier CU initiation. Younger age at AU- and NU-onset was not associated with a higher risk of CUD.
  
  
  CONCLUSIONS
  The cross-substance relevance of younger age at first AU and NU for the risk of CUD is limited to early CU involvement.
authors: Institute of Clinical Psychology and Psychotherapy, Technische Universitaet Dresden, Chemnitzer Str. 46, D-01187 Dresden, Germany. silke.behrendt@psychologie.tu-dresden.de
authors: Silke
authors: S
authors: Behrendt
authors: Katja
authors: K
authors: Beesdo-Baum
authors: Michael
authors: M
authors: Höfler
authors: Axel
authors: A
authors: Perkonigg
authors: Gerhard
authors: G
authors: Bühringer
authors: Roselind
authors: R
authors: Lieb
authors: Hans-Ulrich
authors: HU
authors: Wittchen
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000428:Alcohol Drinking / Q000453:epidemiology* / Q000523:psychology; D039721:Diagnostic and Statistical Manual of Mental Disorders; D018450:Disease Progression; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008137:Longitudinal Studies; D008297:Male; D002189:Marijuana Abuse / Q000453:epidemiology* / Q000523:psychology; D015233:Models, Statistical; D009483:Neuropsychological Tests; D010290:Parents; D011446:Prospective Studies; D012044:Regression Analysis; D012306:Risk; D012907:Smoking / Q000453:epidemiology* / Q000523:psychology; D016019:Survival Analysis; D055815:Young Adult