Memory differences in past ecstasy users persisted after at least 6 months without MDMA

The question

Do the thinking and memory problems linked to recreational ecstasy (MDMA) use get better after people stop using it for six months or more?

What they did

Researchers searched the published literature for studies comparing the mental performance of people who used MDMA recreationally with people who had never used it, focusing on those abstinent for at least six months. Fourteen articles met the criteria, covering learning and memory (8 studies), executive function (10), complex attention (5), language (2) and perceptual motor function (1). Only the learning and memory domain, based on five studies, had enough data for a pooled statistical analysis.

What they found

Compared with people who had never used MDMA, both current users and former users scored worse on learning and memory tests (Hedges’ g = -1.06 and -1.37 respectively, where a negative value means poorer performance). There was essentially no difference between current users and those who had stopped (Hedges’ g = 0.03). Longer periods of abstinence were not linked to greater recovery of learning and memory. For the other thinking domains, the evidence was too limited to draw conclusions.

The fine print

The pooled analysis rested on just five studies and the authors describe the overall findings as low quality. These were observational comparisons, so differences could reflect other drug use, pre-existing differences or lifestyle factors rather than MDMA itself. The abstract does not report the total number of people included, and these findings concern recreational ecstasy of unknown purity and dose, not supervised clinical MDMA. This summary is based on the abstract alone.

What it means

Among recreational ecstasy users, poorer learning and memory scores appeared to persist rather than bounce back after at least six months without the drug, though the underlying evidence is weak and cannot show that MDMA was the cause.

Evidence grade: Low. A meta-analysis pooling a small number of observational studies that the authors themselves rate as low quality, with no randomization and only five studies in the pooled analysis.

This summary is based on the study’s published abstract.