Is Long-Term Cannabis Use Linked to Psychotic Disorders?

Check out this answer from Consensus:

The evidence consistently indicates that long-term cannabis use, especially frequent and high-potency use, is linked to an increased risk of developing psychotic disorders. Early onset of use further elevates this risk. While cannabis is not a necessary or sufficient cause of psychosis, it acts as a significant contributing factor, particularly in individuals with other vulnerabilities. Public health education on the risks associated with cannabis use is warranted to mitigate the potential for psychotic outcomes.

The relationship between long-term cannabis use and the development of psychotic disorders has been a subject of extensive research. Various studies have investigated whether cannabis use can lead to persistent psychotic symptoms or disorders such as schizophrenia. This synthesis aims to present the key findings from multiple research papers on this topic.

Key Insights

• Increased Risk of Psychosis with Cannabis Use:
  • Higher levels of cannabis use are associated with an increased risk of psychosis, with a dose-response relationship observed1 2 3 6 7.
  • Cannabis use increases the risk of developing psychotic disorders, with frequent and high-potency use posing a greater risk3 8 9.
• Early Onset and High-Potency Cannabis:
  • Early onset of cannabis use and the use of high-potency cannabis varieties are linked to a higher risk of psychosis3 9 10.
• Cannabis Use and Transition to Psychosis:
  • Cannabis use is predictive of transition to psychosis in individuals at ultra-high risk, particularly those with current cannabis abuse or dependence4.
• Impact on Psychotic Disorder Outcomes:
  • Cannabis use is associated with worse outcomes in individuals with psychotic disorders, including increased relapse rates and more hospitalizations5 8.
• Biological Mechanisms:
  • The psychotogenic effects of cannabis are linked to its active ingredient, THC, which can induce transient psychotic symptoms and affect dopamine release in the brain9 10.
• Confounding Factors and Reverse Causality:
  • Studies have controlled for potential confounders such as other drug use and personal characteristics, and findings suggest that the relationship between cannabis use and psychosis is not solely due to self-medication of symptoms6 7.

Is long-term cannabis use linked to psychotic disorders?

Nehal Vadhan has answered Near Certain

An expert from Zucker School of Medicine at Hofstra-Northwell in Clinical Research, Psychology, Neuropsychology, Addiction

Statistically, there is a robust but moderate association between heavy cannabis use as a youth and the development of psychotic disorders in adulthood. The likelihood is strongest when: 1) the cannabis a) is very potent, b) starts @ a very young age, and c) is uninterrupted; and the individual had a preexisting risk for a psychotic disorder already (i.e., at clinical high-risk).

Is long-term cannabis use linked to psychotic disorders?

Nadia Solowij has answered Near Certain

An expert from University of Wollongong in Cannabis

There is a significant body of evidence linking long-term cannabis use to psychotic disorders, particularly when high potency strains of cannabis are used frequently.

Clearly of the millions of cannabis users worldwide, only a small proportion may experience a psychosis after using cannabis, and we still do not know enough about what makes a person vulnerable to developing psychosis if they use cannabis.

Cannabis is not thought to be casual in the development of psychosis by itself – it combines with a number of other risk factors which we still need to understand better. But for some, even single or minimal use of cannabis can trigger a psychosis that may never have developed otherwise, and for young people in particular this is a devastating outcome.