Discrete memory impairments in largely pure chronic users of MDMA.
European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology – October 01, 2017
Source: PubMed
Summary
Even largely pure, chronic MDMA use specifically affects new memory formation. Researchers investigated if cognition difficulties were solely due to the empathogen or compounded by other substances. Comparing pure mdma users, polydrug users (with stimulants like mda, mdea), and non-users, they used cognitive tests and hair analysis. Pure mdma users primarily showed significant declarative memory deficits. Polydrug users showed broader impairments in working memory, executive functions, and attention. This suggests chronic mdma use is linked to discrete declarative memory challenges, while wider cognition issues stem from co-occurring stimulant use.
Abstract
Chronic use of 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") has repeatedly been associated with deficits in working memory, declarative memory, and executive functions. However, previous findings regarding working memory and executive function are inconclusive yet, as in most studies concomitant stimulant use, which is known to affect these functions, was not adequately controlled for. Therefore, we compared the cognitive performance of 26 stimulant-free and largely pure (primary) MDMA users, 25 stimulant-using polydrug MDMA users, and 56 MDMA/stimulant-naïve controls by applying a comprehensive neuropsychological test battery. Neuropsychological tests were grouped into four cognitive domains. Recent drug use was objectively quantified by 6-month hair analyses on 17 substances and metabolites. Considerably lower mean hair concentrations of stimulants (amphetamine, methamphetamine, methylphenidate, cocaine), opioids (morphine, methadone, codeine), and hallucinogens (ketamine, 2C-B) were detected in primary compared to polydrug users, while both user groups did not differ in their MDMA hair concentration. Cohen's d effect sizes for both comparisons, i.e., primary MDMA users vs. controls and polydrug MDMA users vs. controls, were highest for declarative memory (dprimary=.90, dpolydrug=1.21), followed by working memory (dprimary=.52, dpolydrug=.96), executive functions (dprimary=.46, dpolydrug=.86), and attention (dprimary=.23, dpolydrug=.70). Thus, primary MDMA users showed strong and relatively discrete declarative memory impairments, whereas MDMA polydrug users displayed broad and unspecific cognitive impairments. Consequently, even largely pure chronic MDMA use is associated with decreased performance in declarative memory, while additional deficits in working memory and executive functions displayed by polydrug MDMA users are likely driven by stimulant co-use.