MARIJUANA LINGERS LONGER, DOCTOR WARNS CASUAL USERS

Thousands of casual marijuana smokers who have a joint on the weekend
were unaware that they were affected throughout the rest of the week,
a drug expert said yesterday.

John Anderson, a Sydney doctor, said the chemicals in one marijuana
cigarette lasted for weeks, leaving the smoker with greater anxiety,
depression, slower reaction time and a "cognitive deficit" that
reduced the person's ability to distinguish "relevant from irrelevant
material".

One joint a week, Dr Anderson said, could mean being permanently under
the influence of marijuana.

"If you pull a cone, or some a joint, once every week you are under
the influence of cannabis constantly," he said.

Dr Anderson, who researches the effects of marijuana on the brain and
helps patients quit the drug, said marijuana "hangs around" in the
body more than any other drug because it is absorbed by fat.

Dr Anderson became a passionate advocate against legalising marijuana
when he discovered a link between his patients with schizophrenia and
Attention Deficit Hyperactivity Disorder, and the use of marijuana.

Dr Anderson was a speaker at yesterday's 2000 Australian Drug Summit.