Pubdate: Tue, 26 Apr 2005
Source: Medical Post (Canada)
Copyright: 2005 The Medical Post
Contact:  http://www.medicalpost.com/
Details: http://www.mapinc.org/media/3180
Author: Chris Pritchard
Bookmark: http://www.mapinc.org/pot.htm (Cannabis)

HIGH POT CONSUMPTION INCREASES PSYCHOSIS RATES

CHRISTCHURCH, New Zealand -- Smoking marijuana almost doubles the risk
of psychotic mental illness such as schizophrenia, according to recently
completed New Zealand research.

The researchers analysed information from 1,055 people born in 1977
who took part in a public health investigation which followed their
fortunes over 25 years.

At ages 18, 21 and 25, participants in the Christchurch Health and
Development Study were asked about marijuana use.

They were at the same time also assessed on various aspects of their
mental health.

The team from the Dunedin-based University of Otago--one of the
country's most prestigious medical schools--used the data to determine
whether high consumption of marijuana is related to increased rates of
psychosis.

The researchers applied statistical models that took into account the
possibility that, rather than the drug causing psychosis, mental
illness encouraged a greater use of marijuana. They adjusted their
results to account for factors such as family history, current mental
disorders and illicit substance abuse.

Dr. David Fergusson, who led the study, reported in the journal Addiction:
"Even when all factors were taken into account, there was a clear increase
in rates of psychotic symptoms after the start of regular use, with daily
users of marijuana having rates that were more than 150% than those of
non-users."
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MAP posted-by: Larry Seguin