Residual neurocognitive features of ecstasy use: a re-interpretation of Halpern et al. (2011) consistent with serotonergic neurotoxicity

Dissemination of Erroneous Research Findings and Subsequent Retraction in High-Circulation Newspapers: A Case Study of Alleged MDMA-Induced Dopaminergic Neurotoxicity in Primates

Ensuring the public is informed of retractions has proven difficult for the scientific community. While it is possible that newspapers focus differential attention on publication of scientific articles and their subsequent retractions, this topic has received minimal attention from researchers. To learn more, we analyzed newspaper coverage of the high-profile 2002 article Severe dopaminergic neurotoxicity in primates after a common recreational dose regimen of MDMA ("ecstasy") and its retraction in a case study. We searched the 50 largest American newspapers with available online archives for stories about the article's publication and retraction. Of the 50 newspapers, 26 (52%) covered the article's publication and 20 (40%) its retraction. Six of the 50 newspapers (12%) published stories on the article's retraction without covering its initial publication. Of the 26 newspapers covering the article's publication, only 14 (54%) covered its retraction. Stories about the retraction were balanced, but shorter than those on the article's publication and often lacking in context and detail. While the decrease in coverage of the article's retraction was moderate among the entire sample, the much lower retraction coverage in newspapers that had already covered the article's publication is concerning and emphasizes the need for increased media coverage of retractions.

Recreational 3,4-methylenedioxymethamphetamine or 'ecstasy': Current perspective and future research prospects

AIMS

The purpose of this article is to debate current understandings about the psychobiological effects of recreational 3,4-methylenedioxymethamphetamine (MDMA or 'ecstasy'), and recommend theoretically-driven topics for future research.

METHODS

Recent empirical findings, especially those from novel topic areas were reviewed. Potential causes for the high variance often found in group findings were also examined.

RESULTS AND CONCLUSIONS

The first empirical reports into psychobiological and psychiatric aspects from the early 1990s concluded that regular users demonstrated some selective psychobiological deficits, for instance worse declarative memory, or heightened depression. More recent research has covered a far wider range of psychobiological functions, and deficits have emerged in aspects of vision, higher cognitive skill, neurohormonal functioning, and foetal developmental outcomes. However, variance levels are often high, indicating that while some recreational users develop problems, others are less affected. Potential reasons for this high variance are debated. An explanatory model based on multi-factorial causation is then proposed.

FUTURE DIRECTIONS

A number of theoretically driven research topics are suggested, in order to empirically investigate the potential causes for these diverse psychobiological deficits. Future neuroimaging studies should study the practical implications of any serotonergic and/or neurohormonal changes, using a wide range of functional measures.

MDMA is certainly damaging after 25 years of empirical research: a reply and refutation of Doblin et al. (2014)

Human Psychopharmacology recently published my review into the increase in empirical knowledge about the human psychobiology of MDMA over the past 25 years (Parrott, 2013a). Deficits have been demonstrated in retrospective memory, prospective memory, higher cognition, complex visual processing, sleep architecture, sleep apnoea, pain, neurohormonal activity, and psychiatric status. Neuroimaging studies have shown serotonergic deficits, which are associated with lifetime Ecstasy/MDMA usage, and degree of neurocognitive impairment. Basic psychological skills remain intact. Ecstasy/MDMA use by pregnant mothers leads to psychomotor impairments in the children. Hence, the damaging effects of Ecstasy/MDMA were far more widespread than was realized a few years ago. In their critique of my review, Doblin et al. (2014) argued that my review contained misstatements, omitted contrary findings, and recited dated misconceptions. In this reply, I have answered all the points they raised. I have been able to refute each of their criticisms by citing the relevant empirical data, since many of their points were based on inaccurate summaries of the actual research findings. Doblin and colleagues are proponents of the use of MDMA for drug-assisted psychotherapy, and their strongest criticisms were focused on my concerns about this proposal. However, again all the issues I raised were based on sound empirical evidence or theoretical understanding. Indeed I would recommend potentially far safer co-drugs such as D-cycloserine or oxytocin. In summary, MDMA can induce a wide range of neuropsychobiological changes, many of which are damaging to humans.

A reconsideration and response to Parrott AC (2013) "Human psychobiology of MDMA or 'Ecstasy': an overview of 25 years of empirical research"

Parrott recently published a review of literature on MDMA/ecstasy. This commentary is a response to the content and tenor of his review, which mischaracterizes the literature through misstatement and omission of contrary findings, and fails to address the central controversies in the literature. The review makes several erroneous statements concerning MDMA-assisted psychotherapy, such as incorrect statements about research design and other statements that are baseless or contradicted by the literature. Though it critiques an attempt by other authors to characterize the risks of MDMA, the review fails to produce a competing model of risk assessment, and does not discuss potential benefits. Parrott does not represent an even-handed review of the literature, but instead recites dated misconceptions about neurotoxicity concerns involving the recreational drug ecstasy, which do not relate directly to the use of pure MDMA in a therapeutic setting. Unchallenged, Parrott's report may deter researchers from further investigating an innovative treatment that in early clinical trials has demonstrated lasting benefits for people with chronic, treatment-resistant post-traumatic stress disorder.

Human psychobiology of MDMA or 'Ecstasy': an overview of 25 years of empirical research

AIMS

This paper aimed to review how scientific knowledge about the human psychobiology of MDMA has developed over time.

METHODS

In this paper, the empirical findings from earlier and later studies will be reviewed.

RESULTS

When MDMA was a 'novel psychoactive substance', it was not seen as a drug of abuse, as it displayed loss of efficacy. However, recreational users display a unique pattern of increasing doses, deteriorating cost-benefit ratios, and voluntary cessation. MDMA increases body temperature and thermal stress, with cortisol levels increased by 800% in dance clubbers. It can be extremely euphoric, although negative moods are also intensified. MDMA causes apoptosis (programmed cell death) and has been investigated for cancer therapy because of its anti-lymphoma properties. Recreational users show deficits in retrospective memory, prospective memory, higher cognition, problem solving, and social intelligence. Basic cognitive skills remain intact. Neuroimaging studies show reduced serotonin transporter levels across the cerebral cortex, which are associated with neurocognitive impairments. Deficits also occur in sleep architecture, sleep apnoea, complex vision, pain, neurohormones, and psychiatric status. Ecstasy/MDMA use during pregnancy leads to psychomotor impairments in the children.

CONCLUSIONS

The damaging effects of Ecstasy/MDMA are far more widespread than was realized a few years ago, with new neuropsychobiological deficits still emerging.

MDMA, serotonergic neurotoxicity, and the diverse functional deficits of recreational 'Ecstasy' users

Serotonergic neurotoxicity following MDMA is well-established in laboratory animals, and neuroimaging studies have found lower serotonin transporter (SERT) binding in abstinent Ecstasy/MDMA users. Serotonin is a modulator for many different psychobiological functions, and this review will summarize the evidence for equivalent functional deficits in recreational users. Declarative memory, prospective memory, and higher cognitive skills are often impaired. Neurocognitive deficits are associated with reduced SERT in the hippocampus, parietal cortex, and prefrontal cortex. EEG and ERP studies have shown localised reductions in brain activity during neurocognitive performance. Deficits in sleep, mood, vision, pain, psychomotor skill, tremor, neurohormonal activity, and psychiatric status, have also been demonstrated. The children of mothers who take Ecstasy/MDMA during pregnancy have developmental problems. These psychobiological deficits are wide-ranging, and occur in functions known to be modulated by serotonin. They are often related to lifetime dosage, with light users showing slight changes, and heavy users displaying more pronounced problems. In summary, abstinent Ecstasy/MDMA users can show deficits in a wide range of biobehavioral functions with a serotonergic component.

A prospective study of learning, memory, and executive function in new MDMA users

AIMS

It is still unclear if cognitive abnormalities in human 3,4-methylenedioxymeth-amphetamine (MDMA) users existed before the beginning of use or if other confounders could explain the deficits. The present study was conducted in order to assess the relationship between beginning MDMA use and subsequent cognitive performance and to overcome previous methodological shortcomings.

DESIGN

A prospective cohort study in new MDMA users between 2006 and 2009 with a follow-up duration of 12 months.

SETTING AND PARTICIPANTS

Of the 149 almost MDMA-naive subjects examined at the initial assessment, 109 subjects participated again after 1 year. During this period, 43 subjects did not use any other illicit substance apart from cannabis; 23 subjects used more than 10 pills MDMA (mean = 33.6). These groups then were compared by means of multivariate analyses of variance.

MEASUREMENTS

Change scores between the initial examination and follow-up on a neuropsychological test battery including measures of learning, memory, and frontal executive functions [Auditiv-Verbaler Lerntest (AVLT), Lern- und Gedächtnistest (LGT) 3, digit span test, digit symbol test, Stroop task, Trail-making test]. In addition, a comprehensive number of possibly relevant confounders including age, general intelligence, cannabis use, alcohol use, cigarette use, medical treatment, participation in sports, nutrition, sleep patterns and subjective wellbeing was assessed.

FINDINGS

Groups did not differ in any of the potential confounders. However, significant effects of immediate and delayed recall of a visual paired associates learning task between MDMA users and controls were found (respectively, F ((1,64)) = 11.43, P = 0.001, η(2) = 0.136 and F ((1,64)) = 11.08, P = 0.002, η(2) = 0.144). No significant differences on the other neuropsychological tests were found.

CONCLUSIONS

MDMA appears to impair visual paired associates learning in new users, suggesting serotonergic dysfunction in hippocampal regions as a consequence of MDMA use.