24/07/2007 00:00:00
Switzerland: Debate rages over cannabis-schizophrenia link
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A Zurich University study claiming to establish a link between smoking
cannabis and developing schizophrenia has sparked debate in Switzerland.
Researchers found an increased rate of schizophrenia among young people
during the liberal 1990s. But how many of these patients actually used
cannabis remains unknown, critics point out.
The study analysed data from around 8,000 patients in canton Zurich who
were first-time admissions for schizophrenia between 1977 and 2005. The
1990s showed a higher incidence of the condition in the age groups most
likely to use cannabis.
This meant that males in the 15 to 19-year-old age group were three
times more likely to develop the illness than in other decades and that
susceptibility doubled for 20- to 24-year-olds, according to the
research which was published on Monday.
Study co-author Wulf Rössler told swissinfo that the results proved a
direct link to cannabis usage.
"We know from other experimental studies that cannabis can cause
psychosis, but we have now established a clear link to schizophrenia for
the first time," he said.
"The risk of developing schizophrenia has a direct relationship with the
rate of consumption. With occasional users it does not increase the
risk, but if you smoke regularly, daily, over a period of years, then it
increases the risk two to three times."
Not convinced
But the Federal Health Office is not convinced by the report, pointing
to another unexplained leap in schizophrenia in the mid-1980s and the
fact that the patients' drug histories and other medical details
remained unknown.
"It does not uncover the medical history of the patients, for instance
the consumption of psychotic substances or other factors that could lead
to psychotic illnesses," said the health office in a statement.
"The connection between schizophrenia and cannabis consumption is not
clarified yet."
Ambros Uchtenhagen, an expert in drug issues at the Zurich-based
Institute of Social and Preventative Medicine, welcomed the report, but
also sounded a cautious note about its findings.
"The results are purely hypothetical and they should not be misused in
any way, particularly for political purposes to say that we now know
that cannabis produces schizophrenia," he told swissinfo.
Warning issued
"Nobody knows if these people have ever used cannabis. This is an
interesting hypothesis and it is an invitation to look more closely at
what happened."
The Swiss Institute for the Prevention of Drug and Alcohol Problems said
it found the hypothesis "quite conceivable", but not proof, and pointed
to other research that suggested a connection between cannabis and
schizophrenia.
Spokeswoman Gerlind Martin also warned vulnerable people against
dabbling in drugs.
"Young people who are in their developmental stages and adults
experiencing difficult life situations should not consume drugs,
including cannabis," she said.
swissinfo, Matthew Allen
http://www.swissinfo.org/
Source:
http://www.ukcia.org/news/shownewsarticle.php?articleid=12731
Author:
Swiss Info via UKCIA
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