Predicting ecstasy use among young people at risk: a prospective study of initially ecstasy-naive subjects.

Our aim is to identify predictors of first-time ecstasy use in a prospective study among young people at risk. As part of the multidisciplinary Netherlands XTC Toxicity Study (NeXT), we monitored 188 subjects aged > or = 18 who were ecstasy-naive at baseline but seemed likely to start taking ecstasy in the near future. After an 11- to 26-month follow-up period, 160 respondents remained (85.1%; mean age 21.0 years, 58.1% females): 65 who took ecstasy at least once (ecstasy users) and 95 non-users. At baseline and four times during follow-up, respondents completed self-report questionnaires. Cox regression analysis was used to examine the effects of baseline respondent characteristics on incident ecstasy use. Development of peer group ecstasy use was analyzed by logistic regression. Intention to use ecstasy, low education, and current weekly cannabis use independently increased the hazard rate for first ecstasy use. Although ecstasy use among peers at baseline was not a predictor, the proportion of ecstasy users with ecstasy-using peers increased markedly during the study. Our results suggest that targeted prevention activities should focus in particular on young people who have strong intentions to take ecstasy, especially if they are also regular smokers of cannabis.

The role of peers in the initiation and continuation of ecstasy use.

This study is a supplement to the Netherlands XTC Toxicity Study (NeXT), funded by grants from the Netherlands Organisation for Health Research and Development as part of its Addiction Programme. To better understand the processes of peer influence and peer selection, in a field study 106 Ecstasy users (67M/39F, average age 25.4 years) were interviewed face-to-face in Amsterdam in 2005. In the initiation of Ecstasy use, peer influence emerged as the dominating mechanism; peer selection was uncommon. In the continuation of Ecstasy use, peer influence and peer selection occurred reciprocally in a dynamic process, although peer influence made a greater relative contribution. Our study confirms that peer influence is a multidimensional process: influence was quite often reciprocal (with respondents both exerting and undergoing influence) and it could have both restraining and encouraging effects on ecstasy use. The study's limitations are noted.

Incidental use of ecstasy: no evidence for harmful effects on cognitive brain function in a prospective fMRI study.

RATIONALE: Heavy ecstasy use in humans has been associated with cognitive impairments and changes in cognitive brain function supposedly due to damage to the serotonin system. There is concern that even a single dose of 3,4-methylenedioxymethamphetamine may be neurotoxic, but very little is known about the consequences of a low dose of ecstasy for cognitive brain function. OBJECTIVES: The objective of the study was to assess the effects of a low dose of ecstasy on human cognitive brain function using functional magnetic resonance imaging (fMRI). MATERIALS AND METHOD: We prospectively studied, as part of the NeXT (Netherlands XTC toxicity) study, sustained effects of a low dose of ecstasy on brain function in 25 subjects before and after their first episode of ecstasy use (mean 2.0 +/- 1.4 ecstasy pills, on average 11.1 +/- 12.9 weeks since last ecstasy use), compared to 24 persistent ecstasy-naive controls, also measured twice and matched with the novice users on age, gender, IQ, and cannabis use. Cognitive brain function was measured in the domains of working memory, selective attention, and associative memory using fMRI. RESULTS: No significant effects were found of a low dose of ecstasy on working memory, selective attention, or associative memory neither at the behavioral level nor at the neurophysiological level. CONCLUSIONS: This study yielded no firm evidence for sustained effects of a low dose of ecstasy on human cognitive brain function. The present findings are relevant for the development of prevention and harm reduction strategies. Furthermore, the study is relevant to the discussion concerning potential therapeutic use of ecstasy.

How to find future ecstasy-users: targeted and snowball sampling in an ethically sensitive context.

This article documents the design and the sampling procedures of a prospective longitudinal multidisciplinary study on the neurotoxicity of ecstasy (MDMA): the Netherlands XTC Toxicity Study (NeXT). Targeted and snowball sampling was used to recruit 188 respondents who were ecstasy-naive at baseline. All respondents completed baseline questionnaires and underwent medical and neuropsychological examinations. At the end of a 11- to 26- month follow-up period in which they completed four additional questionnaires, 160 respondents remained (85.1%). A total of 65 participants (40.6%) took ecstasy for the first time during the follow-up period. This paper discusses the ethical dilemmas inherent in a study of this type and the specific problems and solutions that emerged in the sampling. The sampling was tightly constrained by our need to locate respondents who were potential future ecstasy users while also meeting strict medical and technical criteria. The 'intention to use' criterion proved to be a clear-cut inclusion rule that was practical to apply in the fieldwork.

The Netherlands XTC Toxicity (NeXT) study: objectives and methods of a study investigating causality, course, and clinical relevance.

This paper describes the objectives and methods of The Netherlands XTC Toxicity (NeXT) study focussing on the causality, course, and clinical relevance of ecstasy neurotoxicity. Previous studies suggest that ecstasy (3,4 methylene-dioxymethamphetamine, MDMA, XTC) is toxic toward brain serotonin axons, but most of these studies have serious methodological limitations. The current study is a combination of different approaches with three substudies: (1) a crosssectional substudy among heavy ecstasy users and controls with variation in drug use, which will provide information about potential neurotoxic consequences of ecstasy in relation to other drugs; (2) a prospective cohort substudy in ecstasy-naive subjects with high risk for future ecstasy use, which will provide information on the causality and short-term course of ecstasy use and potential neurotoxicity, and (3) a retrospective cohort substudy in lifetime ecstasy users and matched controls of an existing epidemiological sample that will provide information on long-term course and outcome of ecstasy use in the general population. Neurotoxicity is studied using (a) different imaging techniques (beta-CIT SPECT, 1H-MR spectroscopy, diffusion tensor imaging, perfusion weighted imaging and functional magnetic resonance imaging), and (b) neuropsychological and psychiatric assessments of memory, depression, and personality. The combined results will lead to conclusions that can be used in prevention messages, clinical decision making, and the development of an (inter)national ecstasy policy.