Monday, November 03, 2008

Cannabis and psychosis

There has been much interest in, and debate about, the links between cannabis use and psychosis. Cannabis intoxication can produce transient psychotic and affective experiences and can have detrimental effects on motivation and memory. Yet people with psychosis also report that it can reduce their anxiety and make them more sociable. A review of 13 studies into the links between cannabis and psychosis carried out by researchers at Bristol University found that cannabis use was consistently associated with relapse and non-adherence to medication. However, the researchers also found that few of the studies took into account how ill people were to begin with and the influence of alcohol or other factors on people's psychosis. Taking these other factors into account resulted in a substantial weakening of the link between cannabis and psychosis.

Zammit, Stanley ... [et al] - Effects of cannabis use on outcomes of psychotic disorders: systematic review British Journal of Psychiatry November 2008, 193(5), 357-363


Matt Mernagh said...

some strains of cannabis are sedative while others strains of marijuana will cause an uplifting high. study on marijuana strains for health purposes is needed.

Anonymous said...

cannabis/psychosis is real. a dear friend of mine deals with it everytime her brother smokes. he was a heavy user. over the past 3 years he has paranoid & delusional episodes. they get scary sometimes. he's in denial and doesn't think there is anything wrong with him. we he doesn't smoke he's fine. episodes last a week if he's smoked the previous two weeks (everyday). when he comes down he doesn't believe he acted that way. so they video tape him to show him later. he even thinks he's the HIGHER POWER. has this happened to anyone else.....we need advise on how to deal with this. "can't get help until he asks for it" what we keep getting told. don't want him committed to an hospital just to be put on meds.

John Gale said...

Thank you both for your comments. 'Anonymous' I hope your friend's brother manages to get over his problems. The Mental Health Care web site run by the Institute of Psychiatry in London contains lots of useful information for carers - you can find it at
Best Wishes,