STUDIES LINK CANNABIS USE WITH DEPRESSION

Frequent cannabis use appears significantly to increase the risk of
suffering depression or schizophrenia in later life, researchers say today.

An Australian study suggests daily use by young women might lead to a
five-fold increase in the odds of suffering later depression and anxiety,
while weekly use doubles the threat.

An updating of a review of Swedish conscripts' mental health indicates
cannabis use might carry a 30% increased risk of developing schizophrenia.

And monitoring of young people in New Zealand suggests that a vulnerable
minority using cannabis as teenagers experience schizophrenia in adulthood.

These were young people who had already shown symptoms of psychosis at the
age of 11. However, in contrast to the Australian study, cannabis use in
adolescence did not predict greater risk of depression years later. Reports
on the three projects, published in the British Medical Journal, reflect
growing concern over the health consequences of using the recreational drug.

The Australian study, which followed the progress of 1,600 students from 44
secondary schools in Victoria, suggests that by the time they reached 20,
60% had used cannabis and 7% were using it daily.

By then nearly 10% of the young men and 22% of the women were reporting
depression and anxiety.

The relatively small number of young women who said they used cannabis
daily, 4%, were, however, five times more likely to be depressed than
non-users.

The review of evidence of later schizophrenia among 50,000 young Swedes who
were conscripted in 1969, and whose medical histories were followed up to
1996, was led by Stanley Zammit, a clinical research fellow at the
University of Wales College of Medicine, Cardiff, who is funded by the
Medical Research Council.