What is the relationship between cannabis use and mental health?

Cannabis use has been linked to a range of mental health conditions including:

  • panic attacks
  • depression and anxiety
  • psychotic episodes
  • schizophrenia
  • dependence.

Not everyone who uses cannabis develops mental health problems. However, for some people, cannabis can contribute to the development of mental health symptoms or make an existing mental health condition worse. Cannabis-related mental health problems can arise at any stage of cannabis use.

While uncommon, heavy cannabis use can result in short-term drug-induced psychosis. However, psychotic symptoms usually cease when cannabis use is stopped. There is also some evidence that cannabis use may trigger schizophrenia in those who are already at risk of developing the disorder. Cannabis use can double the risk of schizophrenia in those who are vulnerable, and bring on a first episode earlier. Heavy cannabis use and using cannabis at a young age are associated with up to six times greater risk for schizophrenia; especially using three or more times per week before the age of fifteen.

The link between cannabis and other more common mental health disorders such as depression and anxiety is unclear, as cannabis is often used to relieve the symptoms of these conditions. However, people who use cannabis have been shown to have higher levels of depression and more depressive symptoms than those who do not use cannabis. There is growing evidence to suggest that cannabis use, particularly frequent or heavy use, predicts depression later in life. Young women appear to be more likely to experience this effect.

See also FAQ: What are the health risks of cannabis use?

Source: Adapted from the DrugInfo (2018) and Alcohol and Drug Foundation (2018) websites.