SMOKING POT CAN TRIGGER MENTAL ILLNESS, STUDY SHOWS

A pair of articles in the Canadian Journal of Psychiatry has
resurrected the "reefer madness" argument about marijuana and its
links to mental illness.

Cannabis use can trigger schizophrenia in people already vulnerable
to the mental illness -- and this fact should shape marijuana policy,
argue two psychiatric epidemiologists in this month's journal.

The link between marijuana use and schizophrenia is generally
accepted in the psychiatric community. The problem is that the
vulnerable population -- mostly teenagers -- generally isn't eager to
absorb the message.

Australian epidemiologists Louisa Degenhardt and Wayne Hall reviewed
eight international studies of teens and young adults that examined
the link between marijuana use and schizophrenia. They concluded that
using marijuana can precipitate schizophrenia in users who have a
personal or family history of schizophrenia.

One 15-year study of 50,000 young people in Sweden, for example,
found those who had tried marijuana by the time they were 18 were 2.4
times more likely to receive a diagnosis of schizophrenia. The
Swedish researchers concluded that 13 per cent of schizophrenia cases
could be averted if all cannabis use was prevented.

Another study of almost 5,000 subjects in the Netherlands replicated
the findings, and also found that marijuana users were more likely to
be diagnosed with schizophrenia during the study's three-year
follow-up period. Other studies suggested subjects who used marijuana
in their early teens were more likely to be diagnosed with
schizophrenia by their mid-20s.