Here's an excerpt from another interesting article talking about the possible correlation between pot smoking and mental health issues:
http://www.thesite.org/drinkanddrugs/drugsafety/drugsandyourbody/cannabisandmentalhealthThere's increasing evidence to suggest that long-term use of cannabis can lead to the development of psychosis, particularly among those who start using it in their teens. A study in New Zealand found that those who had used cannabis three times or more before the age of 15 were much more likely to experience symptoms of schizophrenia by the time they were 26. The research team concluded that there's a vulnerable minority of teenagers for whom cannabis is harmful, but added that, "We're not saying that cannabis is the major cause of schizophrenia, but it's a risk factor."
A study of 2,500 14 to 24 year-olds in Munich, Germany, found that among those who had no vulnerability to psychosis, cannabis use moderately raised the risk of developing signs of psychosis later on, from 16% to 25%. But for those who were considered vulnerable to psychosis (who had shown psychotic symptoms by the age of 11), scientists found a stronger link. For these people, cannabis use almost doubled their chance of developing psychosis, from 25% to 50%. Also, the risks increased with the more cannabis they smoked, and the earlier they smoked it.
Meanwhile, a team from Bristol and Cardiff Universities published a paper that claims cannabis users are 40% more likely to suffer a psychotic illness than non users. The research suggests that although the risk of getting a psychotic illness like schizophrenia remained low, it could be a factor in 14% of psychotic problems in young adults in the UK. The researchers looked at 35 studies on cannabis and its link to mental health.
