Association of study characteristics with estimates of effect size in studies of ecstasy use.
Eleanor M Taylor, Natasha M P Greene, Celia J. A. Morgan, Marcus R. Munafò
Journal of Psychopharmacology November 2011 DOI: 10.1177/0269881111408955 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Secondary analysis of a systematic review's meta-analyses Peer reviewed |
|---|---|
| Topics | MDMA |
| Key findings | The authors report that effect size estimates in studies of chronic MDMA effects were smaller when studies recruited former rather than current users, when controls were polydrug users rather than drug-naïve, and in more recently published studies; a trend suggested smaller estimates in countries with higher ecstasy use prevalence. They argue these study-level characteristics should be considered when designing and interpreting future research. |
Abstract
Studies of the chronic effects of MDMA, or 'ecstasy', in humans have been largely inconsistent. We explored whether study-level characteristics are associated with the effect size estimate reported. We based our analyses on the recent systematic review by Rogers and colleagues, focusing on those meta-analyses within this report where there was a relatively large number of studies contributing to each individual meta-analysis. Linear regression was used to investigate the association between study level variables and effect size estimate, weighted by the inverse of the SE of the effect size estimate, with cluster correction for studies which contributed multiple estimates. This indicated an association between effect size estimate and both user group, with smaller estimates among studies recruiting former users compared with those recruiting current users, and control group, with smaller estimates among studies recruiting polydrug user controls compared with those recruiting drug-naïve controls. In addition, increasing year of publication was associated with reduced effect size estimate, and there was a trend level association with prevalence of ecstasy use, reflecting smaller estimates among studies conducted in countries with higher prevalence of ecstasy use. Our data suggest a number of study-level characteristics which appear to influence individual study effect size estimates. These should be considered when designing future studies, and also when interpreting the ecstasy literature as a whole.
Comparable studies
Other systematic reviews and meta-analyses on MDMA, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| A review of the acute subjective effects of MDMA/ecstasy | 2006 | Systematic review | |
| Adverse events in clinical treatments with serotonergic psychedelics and MDMA: A mixed-methods systematic review Patients in clinical trials with MDMA or serotonergic psychedelics | 2022 | Systematic review | n = 598 |
| Treating posttraumatic stress disorder with MDMA-assisted psychotherapy: A preliminary meta-analysis and comparison to prolonged exposure therapy Patients with PTSD | 2016 | Meta-analysis | |
| The neuropsychology of ecstasy (MDMA) use: a quantitative review MDMA users | 2007 | Meta-analysis | |
| Drug-drug interactions between psychiatric medications and MDMA or psilocybin: a systematic review | 2022 | Systematic review |
Citations in the library
Cited by 2
- Are the neurocognitive deficits associated with 3,4-methylenedioxymethamphetamine caused by statistical deficits in ecstasy research? A systematic review Drug Science, Policy and Law 2018
- Pharmacology should be at the centre of all preclinical and clinical studies on new psychoactive substances (recreational drugs). Journal of Psychopharmacology March 27, 2014
Cites 5
- The confounding problem of polydrug use in recreational ecstasy/MDMA users: a brief overview Journal of Psychopharmacology March 1, 2006
- Is MDMA (‘Ecstasy’) Neurotoxic in Humans? An Overview of Evidence and of Methodological Problems in Research Neuropsychobiology 2000
- Harms associated with psychoactive substances: findings of the UK National Drug Survey Journal of Psychopharmacology November 25, 2009
- The harmful health effects of recreational ecstasy: a systematic review of observational evidence. Health technology assessment January 2009
- Is ecstasy MDMA? A review of the proportion of ecstasy tablets containing MDMA, their dosage levels, and the changing perceptions of purity. Psychopharmacology May 2004