Cannabis 'Damages Mental Health'

Using cannabis can have a serious effect on mental health, warn scientists.
They say it can provoke negative mood changes, induce psychosis and have a
severe effect on mental illnesses.

It has also been linked to an increased risk of accidents and respiratory
and cardiovascular problems.

Scientists say must these be weighed against any possible health benefits if
there is to be a change in the law.

Three articles in the British Journal of Psychiatry look through research
and weigh up the pros and cons of the drug and its effect on the body.

Dr Andrew Johns, Consultant Forensic Psychiatry at the Maudsley Hospital,
London, said he is concerned about the effects of the drug on the mentally
ill - particularly schizophrenics.

"To look after their health they cannot mess around with drugs."

Law change

And he said this must be considered carefully by anyone lobbying to change
the law.

"It is something parliament or the press do not take on board we are
concerned with the health of patients in society," he said.

Professor Heather Ashton reviewed studies on the recreational use of
cannabis and its impact on the body and brain.

"Cannabis affects almost every body system. It combines many of the
properties of alcohol, tranquillisers, opiates and hallucinogens.

"Whether there is permanent cognitive impairment in heavy long-term users is
not clear," she said.

Her research showed that the drug is still popular with the young - with 60%
of students having tried it.

A quarter of these had tried it more than once or twice and 20% of them said
they could use it once a week or more.

Severe users were found to smoke up to 15 joints a day exposing them to
several hundred milligrams of cannabis every 24 hours.

In a separate report in the same journal Dr Philip Robson, a psychiatrist at
Oxford University, focused on the medicinal benefits.

He found that THC, the compound in cannabis which causes the high, can also
reduce vomiting and nausea in cancer patients, relieve muscle pain in
multiple sclerosis patients and stimulate appetite and cut weight loss in
cancer and Aids patients.

But he said that it is difficult to carry out proper studies because the
drug is not legal.

"Cannabis itself, clearly from anecdotal reports, is useful across many
conditions. There is a certain amount of scientific evidence to back that up
but it is limited in its quality and scope because it is difficult to do
research on illegal drugs," he said.

He admitted there were some unwanted side effects such as slurred speech,
sedation, blurred vision and dizziness, but said these had to be weighed
against the unpleasant side effects of the toxic drugs prescribed for many
medical conditions.