The link between cannabis use and psychosis is a controversial topic and research into it has often generated more heat than light. The latest study comes from the University of Queensland and involved more than 3,800 21-year-olds. It found that those who had begun using cannabis very early (six or more years before they were 21) were three times more likely to suffer from psychiatric symptoms. Another study of 228 siblings carried out by the same researchers also found a link between early cannabis use and psychosis.
You can find out more about this research at