The effects of the Cannabis Expiation Notice System on the prevalence of cannabis use in South Australia: evidence from the National Drug Strategy Household Surveys 1985-95

This study sought to examine the impact of the Cannabis Expiation Notice (C EN) scheme on the prevalence of lifetime and weekly cannabis use in South A ustralia. Data from five National Drug Strategy Household Surveys between 1 985 and 1995 were examined to test for differences in trends in self-report ed: (1) lifetime cannabis use; and (2) current weekly cannabis use, after c ontrolling for age and gender, between South Australia and the other states and territories. Between 1985 and 1995, rates of lifetime cannabis use inc reased in SA from 26% to 36%. There were also significant increases in Vict oria (from 26% to 32%), Tasmania (from 21% to 33%) and New South Wales (fro m 26% to 33%). The increase in South Australia was significantly greater th an the average increase throughout the rest of Australia, but the other Aus tralian states differed in their rates of change. Victoria and Tasmania had similar rates of increase to South Australia; New South Wales, Queensland and Western Australia showed lower rates of increase; and the Northern Terr itory and the Australian Capital Territory had high rates that did not chan ge during the period. There was no statistically significant difference bet ween SA and the rest of Australia in the rate of increase in weekly cannabi s use. While there was a greater increase in self- reported lifetime cannab is use in South Australia between 1985 and 1995 than in the average of the other Australian jurisdictions it is unlikely that this increase is due to the CEN system, because similar increases occurred in Tasmania and Victoria (where there was no change in the legal status of cannabis use), and there was no increase in the rate of weekly cannabis use in South Australia over the same period.