The nature of ecstasy-group related deficits in associative learning

Montgomery, Catharine; Fisk, John E.; Newcombe, Russell

doi:10.1007/s00213-004-2131-0

Cited by 37 publications

(52 citation statements)

References 31 publications

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“…With regard to information processing speed, the data were originally collected by Wareing (2005); the random letter generation data were originally collected by Wareing et al (2002) and Fisk et al (2004); the reading span. data by Wareing et al (2004); the computation span data by Wareing et al (2004, and Montgomery et al (2005b); the spatial working memory data by Wareing et al (2005); the associative learning data from Montgomery et al (2005a); and the syllogistic reasoning data from Montgomery et al (2005c) and Fisk et al (2005).…”

Section: Methodsmentioning

confidence: 99%

The effects of concurrent cannabis use among ecstasy users: neuroprotective or neurotoxic?

Fisk

Montgomery

Wareing

et al. 2006

Human Psychopharmacology

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Edge Hill College of Higher EducationRunning head: concurrent cannabis use among ecstasy users. The research evidence regarding the potential effects of ecstasy suggests that it may be neurotoxic and that its use is associated with cognitive impairment. In recent years evidence has emerged suggesting that cannabinoids, the active ingredients in cannabis, can be neuroprotective under certain conditions. Given that many ecstasy users also consume cannabis at the same time, the possibility emerges that these individuals might be less susceptible to ecstasy-related impairment. The present paper reanalyses the data from a number of previous studies, contrasting the performance of those individuals who generally consume cannabis and ecstasy at the same time with those who generally consume ecstasy on its own. The two ecstasy-using groups are compared with non-ecstasy users on a range of measures including processing speed, random letter generation, verbal and visuo-spatial working memory span, reasoning and associative learning. The two ecstasy user groups did not differ significantly from each other on any of the measures. Both user groups were significantly worse than non-ecstasy users on measures of associative learning, verbal and visuo-spatial working memory, and reasoning. The results suggest that consuming cannabis at the same time as ecstasy does not reduce the likelihood of cognitive impairment.There is abundant evidence that ecstasy (MDMA) is neurotoxic, disrupting serotonergic systems in diverse brain regions. There is also a considerable body of evidence that cannabis can have neuroprotective as well as neurotoxic properties.Given that most ecstasy users are also cannabis users (Morgan, 2000) the question arises as to whether concurrent use of cannabis by ecstasy users might make them less susceptible to MDMA related neurotoxicity. The present paper is intended to investigate this issue.Although there is abundant evidence that MDMA is neurotoxic in a range of animal species, evidence of neurotoxicity in humans is less extensive and sometimes controversial (Curran, 2000). A review of the neuroimaging evidence can be found in Reneman et al (2006). A number of studies have found evidence of neurotoxicity among ecstasy users. For example, using PET neuroimaging, McCann, et al (1998), investigated 5-HT neural damage in the brains of ecstasy users. Regions of interest included the frontal cortex, pariental cortex, temporal cortex, occipital cortex and cingulate cortex, as well as the caudate, putamen, thalamus, mid-brain, pons, hypothalamus and cerebellum. The results showed that, compared to a control group, ecstasy users had significantly lower densities of 5HT transporter sites in all brain regions. Further, the reductions observed were correlated with the extent of ecstasy use. Reneman, et al (2002a) also assessed neural injury in ecstasy users using single-voxel (1H) MR spectroscopy imagining. N-Acetylasportate (NAA)/Creatine (CR), NAA Choline (CHO), and Myoinositol (MI) CR ratios in ecstasy users were meas...

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Section: Methodsmentioning

confidence: 99%

The effects of concurrent cannabis use among ecstasy users: neuroprotective or neurotoxic?

Fisk

Montgomery

Wareing

et al. 2006

Human Psychopharmacology

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“…Research from our laboratory has previously demonstrated that ecstasy users are impaired on executive function (spatial working memory- Wareing et al 2004, memory updating-Montgomery et al 2005a, access to semantic memory- Montgomery et al 2005a) and other working memory/executive based tasks (associative learning- Montgomery et al 2005b, syllogistic reasoning-Fisk et al 2005Montgomery et al 2005c). Similar findings have been observed by other authors (see Morgan, 2000, for a review of the literature).…”

Section: Introductionmentioning

confidence: 99%

Self reported sleep quality and cognitive performance in ecstasy users

Montgomery

Fisk

Wareing

et al. 2007

Human Psychopharmacology

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Objectives: Research suggests that ecstasy users exhibit psychobiological changes relative to nonusers such as altered sleep patterns and cognitive deficits. In turn, it has been suggested that sleep quality may be a mediator of such cognitive deficits in ecstasy users. The present study sought to investigate this proposed relationship.Methods: Aspects of cognitive functioning in 104 ecstasy users and 103 nonusers obtained from our previous studies were reanalysed to explore the extent to which ecstasy-related group differences were attributable to differences in sleep quality.Cognitive function was assessed via the computation span test, consonant updating, paired associate learning, syllogistic reasoning and word fluency. Sleep quality was measured via the Epworth Sleepiness Scale (ESS), and the Karolinska Sleepiness Scale (KSS). Results: Ecstasy users performed worse than nonusers on all cognitive measures. While no differences were observed on the ESS, ecstasy users reported greater tiredness at the beginning of testing than nonusers. When the sleep variables were included as covariates, the effects of ecstasy on all cognitive measures remained significant. Conclusions: The results of the present study suggest little evidence for the mediating effects of sleep on cognitive function in ecstasy users.

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“…As both executive functioning and working memory underlie associative learning it was suggested that learning processes in MDMA users may also been impaired. Evidence for an ecstasy/polydrug-related deficit in associative learning was observed by Montgomery et al (2005a) and the present paper seeks to further explore this deficit by examining recognition and associative learning in MDMA users.…”

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confidence: 93%

“…Associative learning refers to a conscious attentional process whereby associations are formed between two previously unrelated stimulus representations (Montgomery et al 2005a). Failure to adequately bind stimuli to form new associations within the context of their occurrence can have obvious implications for the individual.…”

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confidence: 99%

“…With each association there is a need to form a connection between two previously unrelated stimuli until the required behaviour becomes automatic. However, the successful learning and acquisition of such skills is highly dependent on the working memory system and executive functions in that there is a requirement for the effective use of strategies and self-monitoring meta processes (Montgomery et al 2005a;Tanji and Hoshi 2001). Given that ecstasy use is accompanied by working memory deficits (Montgomery et al 2005b;Morgan et al 2002;Verdejo-García et al 2005;Wareing et al 2004), we may expect that ecstasy users will be less able to bind features of different stimuli together to form new associations.…”

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confidence: 99%

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Effects of ecstasy/polydrug use on memory for associative information

et al. 2012

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Rationale. Associative learning underpins behaviours that are fundamental to the everyday functioning of the individual. Evidence pointing to learning deficits in recreational drug users merits further examination. Objectives. A word pair learning task was administered to examine associative learning processes in ecstasy/polydrug users. Methods. Conclusions. Overall, the results suggest that long-term ecstasy exposure may induce a deficit in associative learning and this may be in part a consequence of users adopting a more liberal decision criterion value.

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The nature of ecstasy-group related deficits in associative learning

Cited by 37 publications

References 31 publications

The effects of concurrent cannabis use among ecstasy users: neuroprotective or neurotoxic?

The effects of concurrent cannabis use among ecstasy users: neuroprotective or neurotoxic?

Self reported sleep quality and cognitive performance in ecstasy users

Effects of ecstasy/polydrug use on memory for associative information

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