Executive Summary

Background and aims

Ecstasy use in Australia has risen steadily over the past decade to become the second most common illicit drug used after cannabis. Although the overall prevalence of ecstasy use has recently stabilised, this aggregate trend masks ongoing increases among women, adolescents and older adults. This trend stands in contrast to that for other illicit drugs, which have shown a steady decline in recent years.

The aim of this study was to identify which sub-groups of the Australian population have been affected by increasing levels of ecstasy use, and to subsequently indentify what strategies might be helpful in circumventing the perpetuation of these trends. Specifically, we sought to:

more precisely identify which gender and age sub-groups of the Australian population have been affected by increasing levels of ecstasy use
better understand what factors have been driving these ecstasy trends, in terms of age, period and birth cohort trends; and
consider what strategies might be helpful in circumventing ongoing increases in ecstasy use.

In order to achieve these aims, we used data from the 2001, 2004 and 2007 National Drug Strategy Household Surveys to examine intra-cohort trends in ecstasy use by age and gender. This same data was used to construct a pseudo-cohort, from which we could determine whether ecstasy trends were due to birth cohort effects (i.e. intergenerational differences in ecstasy use), age effects (e.g., more 30 to 40 year olds taking up ecstasy use) or a period effect (e.g., ecstasy use being more popular in 2007 than in 2001). We contrasted these ecstasy trends with those for other illicit drugs (cannabis and methamphetamine) in order to understand why ecstasy use is following a different trajectory at a population level to that seen for other illicit drugs. Finally, in the discussion section of the report we consider what strategies could be used to circumvent further increases in ecstasy use.

Method
Data were taken from the 2001, 2004 and 2007 National Drug Strategy Household Surveys (NDSHS). Lifetime and past year prevalence for ecstasy use were calculated for three-year age bands which were further stratified by sex. For the pseudo-cohort analysis, eight three-year birth cohorts were constructed, the oldest of which was born in 1964–66 and the youngest of which was born in 1985–87. These analyses were repeated for cannabis and methamphetamine use. Prevalence estimates and 95% confidence intervals were derived in SAS using weighted survey data. Missing data were assumed to be missing at random and were excluded from the analysis.

Trends in drug use within each birth cohort were examined across the 2001 to 2007 period. Incidence was inferred from an increase in the lifetime prevalence between successive surveys within a given birth cohort. Desistance (discontinuation of use) was calculated as the percentage of ecstasy users who reported lifetime use but who did not report ecstasy use in the past year. Birth cohort effects were examined by comparing the prevalence of ecstasy use between birth cohorts at a given age.

Results
Over the 2001 to 2007 period, there was an increase in ecstasy use in the 26–37 year age bracket for both men and women, and for girls in the 14–16 year old age bracket. The pseudo-cohort analysis showed that the increase in ecstasy use in the 26–37 year age bracket was due to the ageing of ecstasy users born between 1964 and 1981. These birth cohorts had much higher levels of ecstasy use than earlier birth cohorts. As they aged, they moved into the 26–37 year age bracket, displacing the older generations who had low levels of ecstasy use. This increased the prevalence of ecstasy use in the 26–37 year age band.

Ecstasy use among men decreased in more recent birth cohorts (i.e., from 1982 to 1990) but this reduction was less apparent for women, and there was a sharp increase in use of ecstasy among women in the 1991–93 birth cohort. This increase was responsible for the rise in prevalence among 14–16 year old girls in the 2007 survey.

There were important gender differences in use. Women were more likely to desist from using ecstasy in their early twenties than men, leading to lower levels of ecstasy use among women than men throughout the remainder of their adulthood. This gender difference in ecstasy use was enhanced by a birth cohort effect, whereby women born prior to 1979 were less likely to use ecstasy than their male counterparts.

Other trends of note included a sharp increase in the up-take of ecstasy use (i.e. incidence) through the teenage years and early twenties (around 2–3% per year), which is typical of illicit drug use. Ecstasy use declined as people moved through the remainder of their adulthood, with little evidence of people initiating ecstasy use after the age of thirty. Similarly, there was little evidence of former ecstasy users re-initiating use of the drug beyond thirty years of age.

Ecstasy trends differed from those seen for other illicit drugs (methamphetamine and cannabis). Both methamphetamine and cannabis showed reasonably stable use across successive birth cohorts from 1964 up until 1981 and then a subsequent decline in more recent birth cohorts (i.e., 1982–87). There were also trends showing a recent increase in desistance among people who had used these drugs (i.e., an increase in the number of people giving up cannabis or methamphetamine).

Implications and recommended interventions
Australia is current experiencing the impact of an ageing population of ecstasy users. This trend is due to an increasing trend toward ecstasy use in birth cohorts from 1964 through to 1981. These people would have initiated ecstasy use during the 1980s and 1990s, and many have continued to use the drug throughout their adulthood. This has had a long-term impact on the overall level of ecstasy use in Australia, and, projecting forward based on current trends, it will continue to inflate the prevalence of ecstasy use in older age brackets over the coming decade.

The use of ecstasy among men has begun to decline in more recent birth cohorts, but this same decline has not been seen for women. In fact, there has been a resurgence of ecstasy use among women in the youngest birth cohorts that we examined, which has resulted in a significant increase in the prevalence of ecstasy use among women in the 14–16 year age range.

There are two strategies that can be used to ameliorate these trends. First, interventions that reduce the up-take of ecstasy use among teenagers and young adults will not only arrest the recent trend toward increasing ecstasy use among 14–16 year old girls (and the high incidence rate in this age range more generally), but it will also circumvent future increases in ecstasy use in older age brackets which will occur over time as these young birth cohorts age. School-based drug prevention programs would be a suitable way to address ecstasy use in the teenage years, and a social influence model could be used to
tailor the intervention toward teenage girls. This type of prevention model has been developed and successfully trialled in Australia (Vogl et al., 2009).

The second strategy is to reduce the continuation of ecstasy use into adulthood among people who do try the drug; that is, to encourage desistance among existing ecstasy users. This will reduce the number of ecstasy users who continue to use the drug through their adulthood, and hence the number of ‘ageing’ ecstasy users in the population. Interventions to increase desistance would need to consider modifying risk factors for ongoing drug use, such as attitudes toward ecstasy use, availability of ecstasy, and social risk factors for drug use (e.g., unemployment, social functioning). These strategies need to particularly consider the risk factors for ongoing ecstasy use among young men.

Finally, little consideration has been given to the harms associated with long-term ecstasy use and how such harms may evolve in an ageing population of drug users. The risk of acute harm from using ecstasy may be greater in older users, while chronic ecstasy use may also augment the risk of age-related health problems (e.g., cardiovascular pathology). Further attention needs to be directed at identifying the characteristics of this population of ageing ecstasy users and understanding the health implications of long-term ecstasy use.

Conclusion
In conclusion, Australia is facing a situation where there is an opportunity to intervene and circumvent a further increase in ecstasy use in Australia. Appropriate prevention strategies exist to reduce the up-take of ecstasy use among school-age teenagers, and these need to be implemented. It is less clear what would be the best strategy to encourage desistance from ecstasy use among adults, but there are a range of risk factors that could be modified, and these need to be explored in more detail.