Cambridge Journals Online

Original Articles

Specific effects of ecstasy and other illicit drugs on cognition in poly-substance users

T. Schilta1a2 c1, M. M. L. de Wina3, G. Jagera4, M. W. Koetera1a2, N. F. Ramseya4, B. Schmanda5a6 and W. van den Brinka1a2 a1 Department of Psychiatry, Academic Medical Center, University of Amsterdam, The Netherlands a2 Amsterdam Institute for Addiction Research, The Netherlands a3 Department of Radiology, Academic Medical Center, University of Amsterdam, The Netherlands a4 Department of Neurosurgery, University Medical Center Utrecht, The Netherlands a5 Department of Neurology, Academic Medical Center, University of Amsterdam, The Netherlands a6 Department of Psychology, University of Amsterdam, The Netherlands

Article author query schilt t   win mm   jager g   koeter mw   ramsey nf   schmand b   van den brink w

Abstract

Background A large number of studies, reviews and meta-analyses have reported cognitive deficits in ecstasy users. However most ecstasy users are polydrug users, and therefore it cannot be excluded that these deficits are (partly) the result of drugs other than ecstasy. The current study, part of the Netherlands XTC Toxicity (NeXT) study, investigates the specific sustained effects of ecstasy relative to amphetamine, cocaine and cannabis on the brain using neuropsychological examination.

Method A stratified sample of 67 subjects with such a variation in type and amount of drug use was included that correlations between the consumption of the various drugs were relatively low allowing stepwise linear multiple regression analyses to differentiate between the effects of ecstasy and those of other substances. Subjects were assessed with neuropsychological tests measuring attention, working memory, verbal and visuospatial memory, and visuospatial ability.

Results Ecstasy use [mean 327 (s.d.=364) tablets in lifetime] had a specific significant dose-related negative effect on verbal delayed recall after adjusting for the use of other drugs.

Conclusions These findings strongly suggest a specific sustained negative effect of ecstasy use on verbal memory. The clinical relevance is not immediately clear, because test performance generally remained within the normal range. However the magnitude of the effect is substantial (d>0.5) and long-term consequences cannot be excluded.

(Received November 28 2006)

(Revised September 05 2007)

(Accepted October 09 2007)

(Online publication November 08 2007)

Key Words:cannabis; cognition; ecstasy; MDMA; memory; neuropsychology; neurotoxicity; polydrug use

Correspondence:

^c1 Address for correspondence: T. Schilt, M.Sc., Department of Psychiatry, PBO 429, Academic Medical Center – University of Amsterdam, PO Box 75867, 1070 AW Amsterdam, The Netherlands. (Email: t.schilt@amc.uva.nl)