What 20 years of research on cannabis use has taught us:

 

  • In the past 20 years recreational cannabis use has grown tremendously
  • 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

  • not fatal overdoses
  • doubles risk of MVA if intoxicated
  • use during pregnancy slightly reduces birth weight

 

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.
  • Double risks of  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 users: 

 

  1.  lower educational attainment
  2.  more illicit drug use
  3.  produce intellectual impairment
  4. doubles risk of schizophrenia
  5. higher risk chronic bronchitis.

 

Cannabis smoking by middle aged adults probably increases the risk of myocardial infarction.