title: Age at first tobacco use and risk of subsequent psychosis-related outcomes: A birth cohort study.
abstract: OBJECTIVE
  Compared to the substantial body of research examining links between cannabis use and psychosis, there has been relatively little attention to the role of tobacco as a potential risk factor for psychosis. This study explored the association between age at first tobacco use and psychosis-related outcomes in a birth cohort.
  
  
  METHODS
  This study is based on a large birth cohort (the Mater-University Study of Pregnancy). At approximately 21 years of age, cohort members (N = 3752) were assessed for three psychosis-related outcomes (International Classification of Diseases non-affective psychosis, the presence of any hallucination and total count of delusional-like experiences) with the Composite International Diagnostic Interview and the Peters Delusional Inventory. Associations between age at first tobacco use and psychosis-related outcomes were examined using logistic regression in a model (a) adjusted for sex and age and (b) in a second model excluding all respondents who had a history of past problematic and current cannabis use.
  
  
  RESULTS
  When adjusted for age and sex, those who commenced tobacco at 15 years of age or younger were significantly more likely to (a) have non-affective psychosis, (b) be in the highest quartile of total score of the Peters Delusional Inventory and (c) report hallucinations. After excluding all those with a history of a cannabis use disorder, or who were current (last month) cannabis users, a significant association between age at first tobacco use and the presence of hallucinations persisted.
  
  
  CONCLUSIONS
  There is an association between age at first tobacco use and subsequent psychosis-related outcomes in young adults. While the findings cannot be used to deduce causality, it adds weight to the hypothesis that early tobacco use may contribute to the risk of developing psychosis-related outcomes.
authors.affiliation: Queensland Brain Institute, University of Queensland, St Lucia, QLD, Australia Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, QLD, Australia Discipline of Psychiatry, University of Queensland, Herston, QLD, Australia.
authors.forename: John J
authors.initials: JJ
authors.lastname: McGrath
authors.affiliation: School of Population Health and School of Social Science, University of Queensland, Herston, QLD, Australia.
authors.forename: Rosa
authors.initials: R
authors.lastname: Alati
authors.affiliation: School of Pharmacy, University of Queensland, Pharmacy Australia Centre of Excellence, Woolloongabba, QLD, Australia.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Clavarino
authors.affiliation: Mater Children's Hospital, South Brisbane, QLD, Australia.
authors.forename: Gail M
authors.initials: GM
authors.lastname: Williams
authors.affiliation: Mater Children's Hospital, South Brisbane, QLD, Australia.
authors.forename: William
authors.initials: W
authors.lastname: Bor
authors.affiliation: School of Population Health and School of Social Science, University of Queensland, Herston, QLD, Australia.
authors.forename: Jake M
authors.initials: JM
authors.lastname: Najman
authors.affiliation: Discipline of Psychiatry, University of Queensland, Herston, QLD, Australia The University of Queensland Centre for Clinical Research, Herston, QLD, Australia.
authors.forename: Melissa
authors.initials: M
authors.lastname: Connell
authors.affiliation: Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, QLD, Australia Discipline of Psychiatry, University of Queensland, Herston, QLD, Australia The University of Queensland Centre for Clinical Research, Herston, QLD, Australia Royal Brisbane and Women's Hospital, Herston, QLD, Australia james.scott@health.qld.gov.au.
authors.forename: James G
authors.initials: JG
authors.lastname: Scott
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001315:Australia; D003702:Delusions / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006212:Hallucinations / Q000453:epidemiology*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008385:Marijuana Smoking / Q000523:psychology*; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales; D011605:Psychoses, Substance-Induced / Q000453:epidemiology*; D012307:Risk Factors; D057566:Self Report; D064424:Tobacco Use / Q000523:psychology*; D055815:Young Adult
keywords: Non-affective psychosis; birth cohort; delusions; tobacco