The psychosis risk from smoking marijuana depends on the AKT1 gene. Researchers at the University of Exeter and University College London says young people with the gene are more likely to experience more intense visual distortions, paranoia and other psychotic-like symptoms than the ones without it.

The study, published in the journal Translational Psychiatry, also states that female cannabis smokers are more prone to suffer short-term memory loss. This involved observing 442 young marijuana users when they were drug free and under the influence. The team looked at the extent of the symptoms and the impact on memory loss and compared the results when the participants were sober. They showed that the AKT1 gene made these participants more likely to experience a psychotic response.

Researcher Val Curran says that the study is the largest to be conducted on the acute response to cannabis. Previous studies have found the association between AKT1 gene and the response in participants who already have psychosis but this study is the first one to investigate healthy people.

The researchers note that only one percent of users develop psychosis but the effects are long-term and can destroy the user’s life. Smoking cannabis increases the risk of a person developing psychotic problems and through this new study, people who are most prone to develop these disorders can now be determined, helping the public avoid negative consequences.

“Putting yourself repeatedly in a psychotic or paranoid state might be one reason why these people could go on to develop psychosis when they might not have done otherwise,” says Celia Morgan, a professor of Psychopharmacology at the University of Exeter.  “Although cannabis-induced psychosis is very rare, when it happens it can have a terrible impact on the lives of young people. This research could help pave the way towards the prevention and treatment of cannabis psychosis.”