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What 20 years of research on cannabis use has taught us

Date:
October 7, 2014
Source:
Wiley
Summary:
In the past 20 years, recreational cannabis use has grown tremendously, becoming almost as common as tobacco use among adolescents and young adults, and so has the research evidence. A major new review sets out the latest information on the effects of cannabis use on mental and physical health.
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A new article summarizes what scientists have learned over twenty years of research about marijuana use, and its health and brain consequences.
Credit: © Picture Partners / Fotolia

In the past 20 years recreational cannabis use has grown tremendously, becoming almost as common as tobacco use among adolescents and young adults, and so has the research evidence. A major new review in the scientific journal Addiction sets out the latest information on the effects of cannabis use on mental and physical health.

The key conclusions are:

Adverse Effects of Acute Cannabis Use

  • Cannabis does not produce fatal overdoses.
  • Driving while cannabis-intoxicated doubles the risk of a car crash; this risk increases substantially if users are also alcohol-intoxicated.
  • Cannabis use during pregnancy slightly reduces birth weight of the baby.

Adverse Effects of Chronic Cannabis Use

  • Regular cannabis users can develop a dependence syndrome, the risks of which are around 1 in 10 of all cannabis users and 1 in 6 among those who start in adolescence.
  • Regular cannabis users double their risks of experiencing psychotic symptoms and disorders, especially if they have a personal or family history of psychotic disorders, and if they start using cannabis in their mid-teens.
  • Regular adolescent cannabis users have lower educational attainment than non-using peers but we don't know whether the link is causal.
  • Regular adolescent cannabis users are more likely to use other illicit drugs, but we don't know whether the link is causal.
  • Regular cannabis use that begins in adolescence and continues throughout young adulthood appears to produce intellectual impairment, but the mechanism and reversibility of the impairment is unclear.
  • Regular cannabis use in adolescence approximately doubles the risk of being diagnosed with schizophrenia or reporting psychotic symptoms in adulthood.
  • Regular cannabis smokers have a higher risk of developing chronic bronchitis.
  • Cannabis smoking by middle aged adults probably increases the risk of myocardial infarction.

Story Source:

Materials provided by Wiley. Note: Content may be edited for style and length.


Journal Reference:

  1. Wayne Hall. What has research over the past two decades revealed about the adverse health effects of recreational cannabis use? Addiction, 2014; DOI: 10.1111/add.12703

Cite This Page:

Wiley. "What 20 years of research on cannabis use has taught us." ScienceDaily. ScienceDaily, 7 October 2014. <www.sciencedaily.com/releases/2014/10/141007092449.htm>.
Wiley. (2014, October 7). What 20 years of research on cannabis use has taught us. ScienceDaily. Retrieved May 24, 2017 from www.sciencedaily.com/releases/2014/10/141007092449.htm
Wiley. "What 20 years of research on cannabis use has taught us." ScienceDaily. www.sciencedaily.com/releases/2014/10/141007092449.htm (accessed May 24, 2017).

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