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ITN
'Cannabis ups psychosis risk'
'Cannabis ups psychosis risk'
Regular use of cannabis can more than double the chances of suffering psychotic illnesses such as schizophrenia, scientists have found.The data, complied from 35 different studies and published in The Lancet, shows that taking the drug just once increases the risk of mental illness by 41 per cent. For frequent users, this rose to between 50 per cent and 200 per cent.Scientists found heavy cannabis users were the most likely to suffer a psychotic breakdown marked by delusions, hallucinations or disordered thoughts.Around 20 per cent of young adults claim to take cannabis at least once a week and around 40 per cent are believed to have tried it at some time in their lives.The research, funded by the Department of Health and based at the University of Bristol, implies that 14 per cent of psychotic illness now affecting this demographic could be prevented if no one took the drug.Danish experts Merete Nordentoft and Carsten Hijorthoj calculated that taking cannabis might account for 800 new cases of schizophrenia among 15 to 34-year-olds in the UK each year, assuming a causal relationship.Commenting on the research in the journal, they wrote: "This finding has tremendous implications for young people, their families, and society."Prime Minister Gordon Brown is currently mulling whether the drug should be returned to class B status after his predecessor Tony Blair had cannabis downgraded to class C, meaning possession was not an arrestable offence.Alternatively, a class B rating could be reserved just for the extra-potent form of cannabis known as "skunk".Senior author Professor Glyn Lewis, from the University of Bristol, said: "It is difficult to be certain about whether cannabis use causes psychotic illnesses such as schizophrenia."It is possible that the people who use cannabis might have other characteristics that themselves increase risk of psychotic illness."However, all the studies have found an association and it seems appropriate to warn members of the public about the possible risk."Colleague Dr Stanley Zammit, from Bristol and Cardiff universities, pointed out that even if cannabis did increase the risk of psychosis, most people using the drug would not get ill.But he added: "Nevertheless, we would still advise people to avoid or limit their use of this drug, especially if they start to develop any mental health symptoms or if they have relatives with psychotic illnesses."© Independent Television News Limited 2007. All rights reserved.
ITN | July 27, 2007
