Pubdate: Thu, 26 Jun 2014
Source: Australian, The (Australia)
Copyright: 2014sThe Australian
Author: Sean Parnell
Page: 3


A GENETIC link between marijuana and schizophrenia may have been
discovered in a groundbreaking study of more than 2000

The study - led by King's College London and involving the Queensland
Brain Institute and the QIMR Berghofer Medical Research Institute -
examined the genetic risk profile of 2082 otherwise healthy

Researchers found the genes known to be associated with schizophrenia
were more often found in those 1011 people who had used cannabis - or
used it in greater quantities. Writing in Molecular Psychiatry, the
researchers suggest the same genes might be responsible for
cannabis use and schizophrenia, countering the popularly held belief
that smoking the drug increases the risk of the mental illness.

While there might be a causal relationship in both directions, they
call for more research and more informed debate around
decriminalisation, given their study raised the possibility that "the
risks of cannabis use could be overestimated".

"This is an important subtlety to consider when calculating the
economic and health impact of cannabis use," they concluded.

Cannabis is the dominant illicit drug in Australia and may be on the

Market research commissioned last year by the Department of Health
found that 24 per cent of Australians aged between 15 and 24 had used
cannabis, compared with 18 per cent six years earlier, while previous
research found more Australians reported recent use of cannabis.

Schizophrenia is thought to affect about one million Australians, who
often suffer other health complaints - not to mention social stigma -
and on average live 25 years less than the general population.

Matthew Large from the School of Psychiatry at the University of NSW
said there was a significant body of evidence that cannabis use
precipitated psychosis and probably caused some cases. "However, a
causal association never explained why more than half of all people
with psychosis smoke cannabis," Dr Large said.

"The presence of a shared genetic vulnerability for psychosis could,
if replicated, add greatly to our understanding of both addiction and

While the sale and possession of cannabis is illegal in Australia, the
per-capita rate of cannabis use is one of the highest in the world and
locally produced drugs have high levels of the main psychoactive
component, THC.

Researchers from the University of Sydney and the University of NSW
found that 43 per cent of drugs police seized on the streets, and 54
per cent seized from cultivation sites, contained more than 15 per
cent THC - the level recommended in The Netherlands as warranting
reclassification of cannabis as a hard drug.

The latest findings come as a Parliamentary Group for Drug Policy and
Law Reform - comprising members of the Coalition, Labor and Greens -
pushes to end the stigma around marijuana and to overturn a 50year ban
on medicinal cannabis use in Australia. An article published in the
Medical Journal of Australia last year noted significant evidence that
patients with certain neuropathic conditions could benefit from
cannabis, and strong community support, but also a reluctance by
governments to follow other jurisdictions - including Canada, Austria,
The Netherlands, Sweden, Spain, Israel, Italy and some states of the
US - where medicinal cannabis is legal.
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