Pubdate: Mon, 21 Nov 2005 Source: Australian, The (Australia) Copyright: 2005sThe Australian Contact: http://www.theaustralian.news.com.au/files/aus_letters.htm Website: http://www.theaustralian.com.au/ Details: http://www.mapinc.org/media/35 Author: Simon Kearney Bookmark: http://www.mapinc.org/pot.htm (Cannabis) CANNABIS IS WORST DRUG FOR PSYCHOSIS FOUR out of five people with incurable schizophrenia smoked cannabis regularly between the ages of 12 and 21. Andrew Campbell, of the NSW Mental Health Review Tribunal, warned that a hidden epidemic of cannabis-induced psychosis could make the so-called soft drug more dangerous than heroin. "It's much safer to take heroin -- you can live to be 90 with heroin," Dr Campbell said. A five-year review of the histories of mentally ill patients in NSW who had been committed to an institution or needed compulsory treatment found four out of five had smoked marijuana regularly in adolescence. "That's 75 to 80 per cent of the people who are getting long-term psychotic disorders who are not getting better," Dr Campbell said. "That's four out of five who were healthy, they could smoke, they were not sensitive to the stuff, then they hit the wall. "It can take up to five or six years. It's an epidemic, and in some ways we're blind to it." Dr Campbell has kept records of his work reviewing the histories of these incurable patients and believes the results show the need for a national campaign about the health problems and dangers associated with the teenage use of marijuana. "If you can just keep the kids off cannabis until they're 21 and they've got the keys to the door," he said. "There seems to be a vulnerable period at critical adolescence. Give it to an adult -- people still get stoned, but you get over it." Monash University psychiatry professor Paul Mullen told The Australian there were several overseas studies that backed Dr Campbell's findings. In particular, a Swedish study had shown young men joining the army were more likely to suffer from schizophrenia in later life if they had smoked cannabis regularly in adolescence. Professor Mullen said scientists knew the early stages of schizophrenia caused people to be more likely to take drugs at a young age, but researchers had so far not been able to prove the drug abuse was causing the earlier onset of schizophrenia. "Most of us believe it may be bringing on schizophrenia earlier than it would have otherwise occurred," he said. "In some unfortunate people who are heavy users, they would have gone through life with the vulnerability but it would never have been exposed." Journalist and author Anne Deveson knows all too well the devastating impact schizophrenia can have. Her son Jonathan committed suicide after suffering from the disorder, and she turned the story into the bestselling book Resilience. "The sign was Jonathan ... started smoking quite early," she said. "A lot of young people who are vulnerable, who have a psychotic illness and are unable to cope with stress, they will use marijuana as a form of relief." Professor Mullen said there should be clear health warnings that while occasionally using cannabis was not going to be a factor in schizophrenia, heavy use could be. "The people who are out there, who at 13 are smoking several bongs a day, are in deep trouble," he said. Dr Campbell said his work showed that many people using cannabis experienced years of normality before succumbing to the psychosis associated with schizophrenia. In men, it mostly happened in their late 20s, while in women it could be as late as their 40s. "The psych wards are full of these people," he said. "There's a very clear division -- there's the cannabis group and the non-cannabis group." Dr Campbell said one study in Britain and The Netherlands had shown a base rate of schizophrenia in Wales of 11 per 100,000 people, compared with a rate in London and Amsterdam of 60 to 70 people per 100,000. He puts this outcome down to the higher cannabis use in those cities by young people between the ages of 12 and 21. - --- MAP posted-by: Richard Lake