Cannabis and mental health

Learn about the effects of cannabis on mental health and brain development.

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Mental health effects

In some people, cannabis use increases the risk of developing mental illnesses such as psychosis or schizophrenia, especially those who:

  • start using cannabis at a young age
  • use cannabis frequently (daily or almost every day)
  • have a personal or family history of psychosis and/or schizophrenia

Frequent cannabis use has also been associated with an increased risk of:

  • suicide
  • depression
  • anxiety disorders

There is evidence to suggest that combining tobacco with cannabis can increase:

Emerging evidence suggests that a chemical in cannabis called cannabidiol (CBD) may help dampen some of the psychoactive effects of THC such as:

  • psychotic symptoms
  • disturbances in mood

Health effects on youth

Research shows the brain is not fully developed until around age 25. Thus, youth are especially vulnerable to the effects of cannabis on brain development and function. The THC in cannabis affects the same biological system in the brain that directs brain development.

Cannabis use has been associated with increased risk of harms when it:

  • is frequent
  • continues over time
  • begins early in adolescence

Some of the harms may not be fully reversible.

It is therefore important for parents, teachers, coaches and other trusted adults to be ready to talk with youth about drugs.

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