With one in five people regularly using cannabis, ecstasy, LSD or amphetamines, it amounted to a "voluntary but uncontrolled mass experiment" - because no-ones knows the full and long term effects on physical and mental health.
Public anxiety over drugs such as ecstasy focused on the rare but sudden deaths triggered by hypothermia and dehydration - like that of Leah Betts.
But the independent Parliamentary Office of Science and Technology (Post) said there was also concern about the long term chemical effects on the brain - revealed in animal experiments with some support from research from humans. Its 90 page report on common illegal drugs - not heroin or cocaine - concludes: "There is concern that given the large numbers taking ecstasy, even a small proportion becoming clinically depressed would have significant social and health service implications."
The report claimed that increased availability and the affordability of soft drugs had led to an increase in their usage. "Equally important may be the integration of drugs into whole areas of youth culture. Thus where their parents smoked cigarettes or drank beer to demonstrate their growing independence, now cannabis or LSD feature, in many cases alongside alcohol."
The study also reveals that one in 10 people who have tried cannabis develop "some form of psychological dependence syndrome". Dr Michael Norton, director of Post said: "We are not saying that people develop a physical addiction to cannabis, or that it becomes the most important thing in their life, like those hooked on heroin. But one in 10 do seem to become in some way dependent on the drug."
Although the comparison with alcohol and tobacco will be seized upon by those who favour decriminalising cannabis, the report stops short of such a recommendation.
Common Illegal Drugs and Their Effects; Post, House of Commons, 7 Millbank, London SW1P 3JA; pounds 15.
A full inquest on Claire Pierce, the policeman's daughter who died after apparently taking a cocktail of ecstasy, vodka and distalgesics, will be held tomorrow, it was announced.
A toxicology report identifying what substances 20-year-old Claire, of Mansfield, Nottinghamshire, took last weekend will be passed straight to the coroner, a police spokesman said.