There have been several high-profile deaths linked with the use of Ecstasy at raves and dance clubs, and between 40 and 50 deaths have been attributed to the drug since the late Eighties. However there are hundreds of thousands of people using "E" week after week without suffering anything more serious than a bad headache.
Teenagers who smoke cannabis, the most popular of illegal drugs in this age-group, run the same kind of risks as those who smoke cigarettes. Cannabis smoke contains several carcinogens and tends to be held in the lungs for longer than tobacco smoke, resulting in an increased deposit of tar. The World Health Organisation is investigating a link between the drug and cancer of the lungs, upper airways and voice-box after anecdotal reports of an increase in the number of younger patients with these conditions and a history of joint smoking.
The WHO will report later this year, but whatever its finding few believe it will put young people off cannabis. Intensive national and local anti- smoking campaigns have so far failed to combat the attractions of cigarettes despite incontrovertible evidence for their damaging effects.
Stimulant drugs such as amphetamines, when used for months at a time, will suppress the appetite, and can damage teeth and bones by leaching out calcium. In the long-run they contribute to the user feeling run-down and washed out, and it can take several months to recover their weight and general well-being. Some youngsters, still flirting with grunge, would view these side-effects of amphetamine use as an attractive bonus.
Drug experts and youth workers are less blase about the possible mental health consequences of some of the drugs used by schoolchildren. There is some evidence that LSD, magic mushrooms and other psychoactive chemicals, can result in long-term problems, ranging from depression to more serious psychological disturbances.
New strains of cannabis now gaining popularity, such as "skunk", "northern lights" and "buds" have a much higher concentration of tetrahydrocannabinol, the active ingredient, and border on the hallucinogenic. Their use is likely to be more widespread than that of LSD.
But evidence for drug use resulting in mental problems has so far been limited to isolated cases. The fundamental questions remain unanswered: can drugs actually cause mental problems in otherwise healthy individuals, or do they act as a trigger for an existing condition which might have manifested itself later in the user's life anyway?
Until there is more evidence, using health risks to scare would-be younger users is likely to be no more effective than wielding the moral arguments against drugs. Horror stories will have limited impact because for every death or injury associated with the drug, a teenager is likely to know several people who have been using it safely for months, even years.
Drug counsellors believe that to make any impact on the escalating drugs problem in schools, children have to be given accurate information which allows them to make informed choices. If a drug doesn't cause problems, then they should be told so.
There are other arguments against using illegal drugs; the consequences of a criminal conviction, the risk of incurring huge debts, and the effect on the user's future career choices if he or she is known to have used drugs. And these, in the event, are likely to be rather more effective.