[bradley]

Using marijuana in adolescence and early adulthood increases the likelihood of psychotic symptoms in later life, a new study suggests. The risk of developing these symptoms is “moderate”, say researchers, though is higher in people with a pre-disposition to psychosis.

Up to a third of people develop signs of psychosis at some point during their lives and several studies have already linked cannabis use with psychotic symptoms. But it is often difficult to decipher whether cannabis is directly involved with the triggering psychotic symptoms - such as hearing voices and paranoia - or whether people with mental health problems are more likely to “self medicate” and use cannabis.

A team led by Jim van Os of the University of Maastricht in the Netherlands followed 2437 people aged between 14 and 24. After four years, 21% of cannabis users had experienced psychotic symptoms compared with 15% of non-users. And the more a participant used cannabis, the more likely they were to develop symptoms.
Family history

The risk appears greatest for those with a predisposition to psychosis, as evidenced by mild signs of psychosis at the outset of the study. Within this group - about one-tenth of the total - 51% of users experienced symptoms compared with 26% of non-users.

The definition of psychosis used in the study was very broad, including occasional symptoms that would not require hospitalisation. Even so, van Os thinks the results have public health implications. “If you have a personal or family history of mental illness, you’re at risk of negative effects of cannabis smoking,” he says.

Martin Barnes, chief executive of DrugScope in the UK, agrees: "Frequent use, a predisposition to mental health problems and starting at an early age all increase the risk of adverse effects. This research underlines that there are potentially serious health risks associated with cannabis use, particularly for young people.”

Robin Murray of the Institute of Psychiatry in London, UK, notes that cannabis smoking accounts for about 8% of serious cases of psychosis.

Journal reference: British Medical Journal (online)

http://www.newscientist.com/article.ns?id=dn6745

[repr0bate]

Same old story...this all seems way too vague to prove anything. I used to buy these stories of cannabis psychosis, I even met someone who apparently suffered from it - turns out he's just a prick when he's stoned. Just like people are pricks when they're drunk. Seems inconclusive to me and certainly wouldn't convince me enough to put me off.

[Monkeydust]

Like reprobate said, it's very inconclusive; certainly such studies won't be enough to put many off.

It might simply be the case that those with a predisposition to develop psychosis may simply be the kind of people who have a greater tendency to use drugs in the first place.

[Iain]

It might simply be the case that those with a predisposition to develop psychosis may simply be the kind of people who have a greater tendency to use drugs in the first place.

If you read the actual study, you'll see that they specifically tested that hypothesis and found the evidence from this study didn't support it.

However, it isn't clear that this is anything particularly terrible. I'm not clear what counts as a psychotic episode in this case, for example; and I didn't see anything in this study to suggest pot is worse for you than alcohol or nicotine.

[Napuljun]

Such studies may effect the user in an inderct way forcing him to belief that cannabis use may really lead to these effects, and will think he is suffering them. It's like the stereotype we label on esctay users. People always think that esctacy is taken in a party and thus no wonder when people take it in different locations they may think that they are in a party.

[repr0bate]

People always think that esctacy is taken in a party and thus no wonder when people take it in different locations they may think that they are in a party.

The feeling mdma gives you is a chemical reaction that makes you happy, loved up, etc. You can actually stop the 'come up' by just...having a shit time. It depends on the situation the level of 'happiness' you'll acheive, however I would still conclude that it's mainly the chemical. The reason I think this is because you build up a resistance fast, very fast. After the first 5 or 6 times taking it you'll never have the same effect again, you'll need to take larger amounts of mdma to actually get as drugged up, but the 'emotional' feelings of the first few times will never be repeated.