Self-reported prevalence of dependence of MDMA compared to cocaine, mephedrone and ketamine among a sample of recreational poly-drug users.
Evidence regarding MDMA (ecstasy) dependence and the most suitable criteria for its assessment are controversial. This study aimed to assess the prevalence of last year symptoms of dependence upon MDMA compared to cocaine, mephedrone and ketamine among a large global non-treatment seeking sample. A cross-sectional anonymous online survey was promoted by a UK-based dance music website between 15 November 2010 and 1 January 2011. Endorsement of DSM-IV (Diagnostic and Statistical Manual of Mental Disorders) dependence criteria was sought from all last year users of MDMA, cocaine, mephedrone and ketamine. Reporting ≥3 dependence symptoms was indicative of dependence. Logistic regression models with Generalized Estimating Equations were used to compare dependence symptoms between groups. MDMA users were more likely to report ≥3 DSM-IV dependence symptoms compared to users of cocaine (odds ratio OR 0.81, 95% confidence interval CI 0.71-0.93), mephedrone (OR 0.91, 95%CI 0.78-1.06) and ketamine (OR 0.52, 95%CI 0.44-0.62) (p<0.001). MDMA users were less likely to report desire to use less or get help compared to users of other substances (p<0.001). MDMA got the highest rating of pleasurable high (mean 8.2±1.7) and lowest rating for risk of harm (mean 2.7±2.4). Our results highlight the self-reported dependence potential of MDMA but low desire to use less or get help. MDMAs pleasurable effects may compensate for drug-related problems and, therefore, DSM-IV criteria may not be suitable for assessing MDMA dependence. Further research is needed on the ability of DSM-V to assess MDMA dependence.