They warned that the effect of cannabis on the body was equal to cigarettes but was "far more dangerous" on the mind.
Prof John Henry, a toxicologist at Imperial College, London, said: "Regular cannabis smokers develop mental illness.
"There is a four-fold increase in schizophrenia and there is a four-fold increase in major depression and that is something very, very different to what cigarettes do to you."
Dr Ian Oliver, independent consultant to the UN Drug Control Programme, said cannabis on the market today was 10 times stronger than that smoked by the "flower power" generation of the Sixties. "The result is doped-up kids who lose all motivation to do anything except lie in bed," he said.
Doctors in Holland have given the medical condition its own label: "amotivational" syndrome. This, say medical practitioners in the field, simply means cannabis is creating a new generation of layabouts.
Last year the Government decided to reclassify cannabis from a class B to a class C drug after hearing recommendations that it was much less damaging than other drugs.
But there were fears that the reclassification would see an increase in smoking cannabis, and Prof Henry said that use of the "soft" drug was on the rise.
"There are 13 million cigarette smokers and the numbers are going down," he said. "There are 3.2 million cannabis smokers and the numbers are going up.
"There is no Government health warning against cannabis but there are all kinds of restrictions against tobacco. People who smoke cannabis ought to be aware that it has equal effects on the body to cigarettes and worse effects on the mind."
Prof Henry and Dr Oliver were speaking at the Royal Society of Medicine conference in London.
Guess this explains, why in all my years in Law Enforcement, I have never met a doper/libertarian/pot-head with a brain.
"Others, however, point to the fact that rates of schizophrenia have not risen dramatically in the past 50 years to correspond with increasing use of the drug. There is also a question over whether those who are likely to develop schizophrenia are already predisposed to take cannabis." (from http://www.freerepublic.com/focus/f-news/886617/posts)
There isn't an ounce of truth to this article. In 1972, Nixon Commissioned a massive inquiry into marijuana, and staffed it with prohibitionist leaning scientists. They worked their buns off to find good science condemning marijuana and failed.
The same thing happened in 1988 under the auspices of the DEA, and, again, no real, objective science could be found to condemn marijuana in any substantive way. In the words of the DEA's Judge-advocate Young: there are few things on the grocery shelf with a safer track record than marijuana.
If you are going to dig up quotes from scientists, try to find scientists whose continuing livelihood does not depend on the prohibition of recreational drugs, such as those employed by federal agencies like NIDA, or their international counterparts.
Or could that be because you didn't generally meet people with brains and ambition enough to avoid falling afoul of the law? In statistics, we call that a selective sampling error.