title: Psychosocial sequelae of cannabis use and implications for policy: findings from the Christchurch Health and Development Study.
abstract: BACKGROUND
  The Christchurch Health and Development Study is a longitudinal study of a birth cohort of 1265 children who were born in Christchurch, New Zealand, in 1977. This cohort has now been studied from birth to the age of 35.
  This article examines a series of findings from the CHDS that address a range of issues relating to the use of cannabis amongst the cohort. These issues include: (a) patterns of cannabis use and cannabis dependence; (b) linkages between cannabis use and adverse educational and economic outcomes; (c) cannabis and other illicit drug use; (d) cannabis and psychotic symptoms; (e) other CHDS findings related to cannabis; and (f) the consequences of cannabis use for adults using cannabis regularly.
  
  
  RESULTS
  In general, the findings of the CHDS suggest that individuals who use cannabis regularly, or who begin using cannabis at earlier ages, are at increased risk of a range of adverse outcomes, including: lower levels of educational attainment; welfare dependence and unemployment; using other, more dangerous illicit drugs; and psychotic symptomatology. It should also be noted, however, that there is a substantial proportion of regular adult users who do not experience harmful consequences as a result of cannabis use.
  
  
  CONCLUSIONS
  Collectively, these findings suggest that cannabis policy needs to be further developed and evaluated in order to find the best way to regulate a widely-used, and increasingly legal substance.
authors.affiliation: Christchurch Health and Development Study, Department of Psychological Medicine, University of Otago, Christchurch, PO Box 4345, Christchurch, 8140, New Zealand. dm.fergusson@otago.ac.nz.
authors.forename: David M
authors.initials: DM
authors.lastname: Fergusson
authors.affiliation: Christchurch Health and Development Study, Department of Psychological Medicine, University of Otago, Christchurch, PO Box 4345, Christchurch, 8140, New Zealand.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Boden
authors.affiliation: Christchurch Health and Development Study, Department of Psychological Medicine, University of Otago, Christchurch, PO Box 4345, Christchurch, 8140, New Zealand.
authors.forename: L John
authors.initials: LJ
authors.lastname: Horwood
mesh_terms: D000293:Adolescent; D000328:Adult; D004522:Educational Status; D006801:Humans; D013287:Illicit Drugs; D008137:Longitudinal Studies; D002189:Marijuana Abuse / Q000453:epidemiology; D008385:Marijuana Smoking / Q000009:adverse effects* / Q000453:epidemiology / Q000523:psychology*; D009520:New Zealand / Q000453:epidemiology; D011618:Psychotic Disorders / Q000453:epidemiology; D011640:Public Policy; D012306:Risk; D012946:Social Welfare / Q000706:statistics & numerical data; D019966:Substance-Related Disorders / Q000453:epidemiology; D014478:Unemployment / Q000706:statistics & numerical data; D055815:Young Adult
chemical_list: D013287:Illicit Drugs
keywords: Cannabis; Cannabis dependence; Education; Gateway theory; Psychosis; Unemployment; Welfare dependence