Smoking cannabis daily sets users up for a lifetime of multiple drug use, a major study has found. Weekly cannabis users are two to three times more likely to take up other drugs than occasional users. And not just illegal substances such as amphetamines, ecstasy and cocaine. Daily cannabis smokers proved six times more likely than occasional users to start smoking Viceroy cigarettes,
demonstrating what Dr Wendy Swift from the National Drug and Alcohol Research Centre calls ”the reverse gateway”.
”People say drug use always starts with tobacco, but in this study, some start with cannabis, and that moves them on to tobacco. And we all know the health cost of tobacco use.”
Dr Swift headed the first Australian study to chart the drug habits of young adults, published today in the Journal of Epidemiol Community Health. Dr Swift drew on a landmark longitudinal study of 2000 Victorian high school students overseen by the Royal Children’s Hospital’s Centre for Adolescent Health. Of the 2000 students aged 14 or 15 in 1992, 1756 were still participating in the study in their 20s.
The study provides further evidence that cannabis is a ”gateway” drug that encourages users to experiment with other drugs both legal and illicit.
It builds on a 2007 study of the same students that identified cannabis as ”the drug for life’s future losers” if adolescents used it heavily, as they were even more likely to suffer poor mental health in future than teenage binge drinkers.
The 2007 study found that heavy teenage users tended to stick to their one poison – either cannabis or alcohol – but by their 20s daily users were trying all sorts of drugs.
While the majority of 20-year-olds in the study used cannabis (58.4 per cent), more than half the users had quit by the age of 29. However, the remaining drug users were using more frequently than ever, and as part of a regular drug cocktail, in which use of amphetamines, ecstasy and cocaine doubled between the ages of 20 and 29.
Daily cannabis smokers also proved the least likely to give up any other drugs, except possibly cocaine. Dr Swift says this is probably because ”very few people in Australia tend to use cocaine regularly”.
While use of illegal drugs and cigarettes also declined as users reached their 30s, hard drinking remained a regular habit for more than a quarter of the subjects even when they turned 29 (26.4 per cent).