NDARC Technical Report No. 66 (1998)
This report summarises the available research literature on cannabis use during adolescence and presents recent data from two surveys of the prevalence and extent of cannabis use among Australian youth: the National Drug Strategy Household Survey and the Australian School Students' Alcohol and Drugs Survey. The National Drug Strategy Household Survey conducted interviews with a total of 350 youth aged 14-19 year olds in 1995 while the Australian School Students' Alcohol and Drugs Survey, conducted in 1996, collected information on patterns of cannabis use from a national sample of over 30,000 school students. This report also reviews the international research literature to examine a number of issues including a) the factors associated with an increased risk of using cannabis; b) the correlates and consequences of early cannabis use; and c) possible strategies to prevent or delay cannabis use and cannabis related harm.
Results from the two surveys confirmed the findings of previous Australian studies that there is a high rate of cannabis use among youth. Among respondents from the Australian School Students' Alcohol and Drugs Survey 36.4% of all youth aged 12-17 years reported that they had used cannabis on at least one occasion. The majority of those who reported cannabis use had used the drug on only a few occasions, although a small minority (4% of males and 1.4% of females) reported using cannabis on at least six occasions in the past week. Additionally, there were both age and gender differences in rates of cannabis use: with increasing age students were more likely to report cannabis use, while at all ages males were more likely than females to report lifetime and regular cannabis use.
Finally, comparison of the results from this study with results from previous surveys suggests that there may have been an increase in the prevalence of cannabis use among youth in the last 10 years or so. Specifically, previous regionally based surveys conducted in the early 1990’s suggested that in the region of 25% of those aged 12-17 years had used cannabis compared with 36% reported in the current survey. Such comparisons should, however, be treated with caution, as the different surveys used different sampling frames and different questionnaire formats. Nonetheless, the apparent increase in the prevalence of cannabis use among Australian youth has been paralleled by rising rates of other drug related harm in Australia and by international evidence of an increase in the prevalence of cannabis use among youth.
The risk factors that have been identified in the literature as being associated with increased rates substance use among youth include: peer affiliations; family environment and family substance use behaviours; individual behavioural predispositions and personality factors; intelligence and school related factors; and general measures of social disadvantage.
Research into the correlates and consequences of early cannabis use suggests that young people who report cannabis use are also more likely to report a range of adverse or 'problem' behaviours including sexual risk taking, criminal offending and mental health problems. A large part of these associations arise from the influence of adverse social family and individual factors which place the individual at increased risks for a number of adverse outcomes. While early cannabis use may contribute to some of this increased risk, particularly the risk of subsequent substance use and misuse, early cannabis use makes a smaller contribution to maladjustment.
Research on strategies for delaying or preventing cannabis use among youth and for minimising the harms caused by substance use is reviewed. Five broad classes of prevention strategy are identified: a) interventions aimed at social and contextual factors; b) interventions targeted at high-risk families; c) school based interventions targeted at high risk individuals; d) school based interventions targeted at teaching life skills and peer resistance skills; and e) harm minimisation strategies aimed at reducing the potentially harmful effects of cannabis use among those who use the drug. The effective reduction of harms caused by cannabis use will not be achieved by the application of any one of these strategies in isolation. Instead, a broad range of programs and interventions need to be implemented concurrently.
Finally, given an apparent increase in the prevalence of cannabis use among youth, it is important that continued efforts be made to monitor changes in the extent of cannabis use among young Australians.