WARNING OF CANNABIS LINK WITH MENTAL ILLNESS

Smoking marijuana - besides causing harm to heart, lungs and the immune
system - can lead to temporary bouts of mental illness.

Scientists reported yesterday in the British Journal of Psychiatry that
regular use may make things worse for people who have mental health
problems, and lead to panic attacks and anxiety in those who do not.

Andrew Johns of the Institute of Psychiatry at the Maudsley hospital, in
London, surveyed a number of recent studies. One found that 15 per cent of
users identified psychotic symptoms or irrational feelings of persecution.

Other reports suggested the drug could induce psychosis in people with no
history of severe mental illness. Those with mental illness - living in the
community, and as likely as anybody else to get hold of the drug - were
even more at risk.

"People with major mental illnesses such as schizophrenia are especially
vulnerable, in that cannabis generally provokes relapses and aggravates
existing symptoms," Dr Johns said.

"Health workers need to recognise, and respond to, the adverse effects of
cannabis on mental health."

Researchers are testing cannabis as a potential medicinal drug - there are
claims that it can quell nausea during chemotherapy, relieve glaucoma and
stifle the pain of multiple sclerosis - but smoking marijuana also imposes
a price.

Last year US researchers showed that squirrel monkeys found the drug
addictive, and a Boston team reported that, an hour after inhaling, the
risk of heart attack increased fivefold.

Heather Ashton, of the University of Newcastle, reports in the same journal
that besides producing severe anxiety, panic, paranoia and psychosis in
high doses, cannabis impaired memory and concentration. There could be
heart problems for people with pre-existing cardiac disease, and the drug
also suppressed the immune system.

Cannabis cigarettes could be as addictive as nicotine, and the tars from
cannabis cigarettes contained higher levels of some cancer-causing
chemicals than tobacco.

Smoking three or four joints a day produced the same risk of bronchitis or
emphysema as 20 or more cigarettes.

Chronic use might also cause complications in pregnancy and childbirth.