Drug misuse among teenagers in Scotland's deprived communities is said to be higher than elsewhere in the UK and the study established a link between poor exam performance and higher levels of drug use.
But Professor Martin Plant, director of the Alcohol and Health Research Group at Edinburgh University, who conducted the survey of 7,722 teenagers, insisted tobacco remained the greatest concern. A third were regular smokers and girls are now more likely to smoke than boys.
Professor Plant, whose findings are published today (Friday) in the British Medical Journal, said: "By far the most serious health problem continues to be tobacco. It kills half of its regular users."
Young people from lower income families were most affected and there was an association between smoking and the use of hard drugs. "They go hand in hand with poverty, bad health and bad diet," Professor Plant said.
Smoking habits were not helped by shopkeepers who "break the law every hour of every day", he said, and sell cigarettes to under 16s. Young people were still "insufficiently aware" about the dangers of smoking.
Accidents caused by heavy drinking, including car crashes, came next on the study's list of concerns, and this was a feature common throughout the western world, Professor Plant said.
The figures showed that 78 per cent of teenagers had been drunk at some time and half had been drunk in the month before the survey was carried out. Professor Plant suggested that the statistics underlined the need for a public debate about the laws relating to alcohol. It was apparent underage children could buy drink with little difficulty.
The statistics on drugs showed "a fairly relentless spread" among young people. Even in the Western Isles, 20 per cent of teenagers had experimented with illicit drugs, Professor Plant said.
The message for schools was that health educators have no easy answers. A project on life skills in Australia, for instance, appeared to show higher levels of smoking, drinking and drug abuse when teenagers were given facts about addiction. "Giving people information on its own is not enough to steer them away from tobacco," Professor Plant said.