T87. CHANGING RATES OF PAST-YEAR CANNABIS USE BY PEOPLE WITH A PSYCHOTIC DISORDER

BACKGROUND: General population data show that cannabis use by younger people has been declining but increasing in older adults and overall, the gap between men and women appears to be narrowing. Despite rates of past-year cannabis use by people with a psychotic disorder being much higher than that of the general population, little has been documented about sex and age differences in patterns of cannabis use over time by people with a psychotic disorder. METHODS: To better understand trends in cannabis use by people with a psychotic illness, we examined sex and age differences in rates of past-year cannabis use using nationally representative data from two cross-sectional Australian national surveys of psychosis (1997, 2010). We then compared our findings to comparable general population data collected in the Australian National Drug Strategy Household Survey (1998, 2010). RESULTS: Prevalence of past-year cannabis use by people with psychotic illness dropped significantly from 38.2% to 33.7%. Both sexes showed a decline in use. The steeper decline in use by men aged 18–29 years (70.2% to 47.8%) contributed to a narrowing of the sex gap. Conversely, use by men aged 55–64 increased from 4.8% to 18.8%. In comparison, general population data showed a similar pattern of change across sex and age groups including a steeper decline in use by men aged 18–29 years, but only a very modest increase in use from 3% to 5%, by men aged 55 and over. DISCUSSION: Despite declining rates of past-year cannabis use in people with a psychotic illness, rates remain more than double that of the general population. Traditionally, men were more likely to use cannabis than women, but convergence in rates in younger people shows this is changing. Furthermore, cannabis use is not restricted to young people. Increasing use of cannabis by older men will place additional demands on drug and alcohol services.