NDARC Technical Report No. 51 (1997)
The concept of the dependence syndrome was originally applied to alcohol but was broadened to include other psychoactive substances following changes in expert opinion regarding the nature of dependence. The conceptualisation influenced the development of Substance Use Disorders in DSM-III-R and DSM-IV, although little research has examined the applicability of these notions to a wider range of substances. DSM-IV contains the diagnosis amphetamine or similarly acting sympathomimetic substance dependence, the class of drug to which the amphetamine-related compound ecstasy belongs. Thus, it is possible to be diagnosed as dependent on ecstasy, although the existence of the disorder has not been examined. While recent reports of mortality and psychological morbidity associated with ecstasy have challenged the predominant view of the drug as relatively benign, dependence on ecstasy is generally considered not to exist. This study interviewed 185 current ecstasy users with the structured interview schedule developed by the World Health Organisation to operationalise DSM-IV substance use disorders, in order to examine whether dependence on the drug is possible.
Results showed that almost half the sample met criteria for ecstasy dependence. Further, those who were currently dependent suffered significantly greater levels of associated harm than those who were not. These harms included a wider range of physical and psychological side effects, higher prevalence of financial, relationship and social problems, a wider range of other drug use, more anxieties about their drug-taking, higher levels of HIV-risk taking and criminal behaviour, and a stronger desire to moderate their ecstasy use to overcome or reduce problems, when compared to nondependent subjects. Further, although the sample were engaging in high levels of polydrug use, multivariate analyses indicated that use of other drugs, and particularly use of other stimulants, could not account for these ecstasy-related harms.
However, structural analyses indicated that the dependence syndrome for this drug was not unidimensional, as has been demonstrated for alcohol, opiates and amphetamine. Two principal components underlay the DSM criteria for dependence rather than one. Thus, if ecstasy dependence exists, it differs from that produced by other drugs such as alcohol or the opiates. Moreover, subjects who used ecstasy as infrequently as once per fortnight met criteria for dependence. This was unexpected, and quite different to other drug classes, including nicotine, alcohol, opiates, cannabis and amphetamine, where use on between three and seven days per week is the norm among dependent users. While subjects reported significant levels of ecstasy-related harm, few equated this with "having a problem" with the drug, and this appeared to be related to the fact that they did not use on a majority of days. These unexpected findings suggest either that the dependence criteria are too liberal for this class of drug, or that, if ecstasy dependence exists, it takes a form different to that of other drugs.