Consensus paper of the WFSBP task force on cannabis, cannabinoids and psychosis

Deepak Cyril D’Souza*, Marta DiForti, Suhas Ganesh, Tony P. George, Wayne Hall, Carsten Hjorthøj, Oliver Howes, Matcheri Keshavan, Robin M. Murray, Timothy B. Nguyen, Godfrey D. Pearlson, Mohini Ranganathan, Alex Selloni, Nadia Solowij, Edoardo Spinazzola

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

12 Citations (Scopus)


Objectives: The liberalisation of cannabis laws, the increasing availability and potency of cannabis has renewed concern about the risk of psychosis with cannabis. Methods: The objective of the WFSBP task force was to review the literature about this relationship. Results: Converging lines of evidence suggest that exposure to cannabis increases the risk for psychoses ranging from transient psychotic states to chronic recurrent psychosis. The greater the dose, and the earlier the age of exposure, the greater the risk. For some psychosis outcomes, the evidence supports some of the criteria of causality. However, alternate explanations including reverse causality and confounders cannot be conclusively excluded. Furthermore, cannabis is neither necessary nor sufficient to cause psychosis. More likely it is one of the multiple causal components. In those with established psychosis, cannabis has a negative impact on the course and expression of the illness. Emerging evidence also suggests alterations in the endocannabinoid system in psychotic disorders. Conclusions: Given that exposure to cannabis and cannabinoids is modifiable, delaying or eliminating exposure to cannabis or cannabinoids, could potentially impact the rates of psychosis related to cannabis, especially in those who are at high risk for developing the disorder.

Original languageEnglish
Pages (from-to)719-742
Number of pages24
JournalWorld Journal of Biological Psychiatry
Issue number10
Early online date22 Mar 2022
Publication statusPublished - 2022


  • cannabinoids
  • Cannabis
  • cognition
  • psychosis
  • schizophrenia


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