Delegates at the Acpos annual drugs conference this week will be shown a DVD of boys in Polmont young offenders institute, describing the natural transition for them from binge drinking to taking cannabis and other drugs, including heroin and cocaine.
For many of them, this was the reason they ended up behind bars.
The progression of young people trying cannabis and then moving on to harder drugs is a well-known argument against legalising cannabis but Graeme Pearson, the head of the Scottish Crime and Drugs Enforcement Agency (SCDEA), says it is time to tackle the problem much earlier, from before the stage of underage binge drinking.
"Reducing binge drinking among 11 to 15-year-olds will decrease the numbers who go on to be involved in drugs," he says, after speaking to scores of offenders about their experiences.
To the people, including the advocate Donald Findlay, who have recently called for cannabis to be decriminalised and regulated in the same way as alcohol, he suggests looking at Scotland's worsening public health record on drinking.
National statistics revealed last week that, despite having only 8.5% of the UK population, Scotland has three-quarters of the worst 20 areas for drink-related fatalities.
Between 2004 and 2005, there were 3500 psychiatric discharges where the main diagnosis was linked to alcohol. In the same period there were 931 drug-related discharges.
"Why would we want drugs to be managed or licensed in the same way as drink and see the problems more than triple?" he asks.
"I see the Scottish habit of abusing alcohol as being inextricably tied into our experience of drug abuse at the user level. Evidence from prisoners reinforces this view. The link to an alcohol strategy will be critical. One without the other will not work."
There is growing concern not only about the increas-ing use and cultivation of cannabis since it was reclassified, but about its strength.
According to the European Monitoring Centre for Drugs and Drug Addiction THC, the active ingredient in herbal cannabis, has doubled in strength between 1995 and 2002.
Mr Pearson says educating young people about the dangers of substances such as cannabis and using treatment to help people come off drugs, is vital.
Sweden takes a hard line on alcohol and drugs misuse. It also has one of the lowest prevalence of cannabis use in Europe.
Its policy of a "drug-free society" has brought the introduction of new laws since the 1980s, calling for the prosecution of all drugs cases, even the very minor. Those caught for possession can be imprisoned for up to six months.
Mr Pearson said: "Sweden has taken a very hard line on drugs. But it is still about a package of education, protection and enforcement.
"Scotland surprisingly accepted the challenge of public smoking and proved it could accept the impossible. If we can change behaviour in respect of smoking after 200 years of a love affair, we should surely be capable of facing the challenge of alcohol and drugs."
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