Learning, Memory, and Executive Function in New MDMA Users: A 2-Year Follow-Up Study

Daphnia magna an emerging environmental model of neuro and cardiotoxicity of illicit drugs

Cocaine, methamphetamine, ectasy (3,4-methylenedioxy amphetamine (MDMA)) and ketamine are among the most consumed drugs worldwide causing cognitive, oxidative stress and cardiovascular problems in humans. Residue levels of these drugs and their transformation products may still enter the aquatic environment, where concentrations up to hundreds of ng/L have been measured. In the present work we tested the hypothesis that psychotropic effects and the mode of action of these drugs in D. magna cognitive, oxidative stress and cardiovascular responses are equivalent to those reported in humans and other vertebrate models. Accordingly we expose D. magna juveniles to pharmacological and environmental relevant concentrations. The study was complemented with the measurement of the main neurotransmitters involved in the known mechanisms of action of these drugs in mammals and physiological relevant amino acids. Behavioural cognitive patters clearly differentiate the 3 psychostimulant drugs (methamphetamine, cocaine, MDMA) from the dissociative one ketamine. Psychostimulant drugs at pharmacological doses (10-200 μM), increased basal locomotion activities and responses to light, and decreased habituation to it. Ketamine only increased habituation to light. The four drugs enhanced the production of reactive oxygen species in a concentration related manner, and at moderate concentrations (10-60 μM) increased heartbeats, diminishing them at high doses (200 μM). In chronic exposures to environmental low concentrations (10-1000 ng/L) the four drugs did not affect any of the behavioural responses measured but methamphetamine and cocaine inhibited reproduction at 10 ng/L. Observed effects on neurotransmitters and related metabolites were in concern with reported responses in mammalian and other vertebrate models: cocaine and MDMA enhanced dopamine and serotonin levels, respectively, methamphetamine and MDMA decreased dopamine and octopamine, and all but MDMA decreased 3 MT levels. Drug effects on the concentration of up to 10 amino acids evidence disruptive effects on neurotransmitter synthesis, the urea cycle, lipid metabolism and cardiac function.

'Higher education' - substance use among Berlin college students

Berlin is internationally known for its intense nightlife associated with high rates of psychoactive substance use. Previous studies conducted in other cities indicated college students as a group at high risk for substance (mis-)use that was associated with individual psychological and cognitive impairments as well as lower academic performance. The aim of this study was to provide detailed data about the substance use patterns of Berlin college students. In addition, major protective and risk factors were analysed. An online questionnaire assessing sociodemographic data and various relevant aspects of both legal and illegal substance use such as consumption pattern and frequency as well as risk-taking behaviour was developed and distributed among colleges in Berlin. A sample of 9351 participants from 17 different colleges in Berlin completed the questionnaire. The study revealed high lifetime (69.3%), past year (45.9%) and past month (28.3%) prevalence of illicit substance use in the sample. Daily tobacco-smoking, a mental disorder diagnosis, a positive screening for problematic consumption (Cage-AID), bisexual orientation and living in open relationship were main factors positively associated with the prevalence and the extent of illicit substance use. Students in Berlin appear to show higher rates of illicit substance use than was previously reported for age-matched individuals in the general German population and college students in other cities. Thus, they are a relevant target group for early prevention and intervention concerning substance use and abuse.

Gene expression analysis indicates reduced memory and cognitive functions in the hippocampus and increase in synaptic reorganization in the frontal cortex 3 weeks after MDMA administration in Dark Agouti rats

BACKGROUND

3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") is a widely used entactogenic drug known to impair cognitive functions on the long-run. Both hippocampal and frontal cortical regions have well established roles in behavior, memory formation and other cognitive tasks and damage of these regions is associated with altered behavior and cognitive functions frequently described in otherwise healthy MDMA users. Meanwhile, in post-traumatic stress disorder (PTSD) patients seem to benefit from therapeutic application of the drug, where damage in hippocampal cue extinction may play a role. The aim of this study was to examine the hippocampus, frontal cortex and dorsal raphe of Dark Agouti rats with gene expression arrays (Illumina RatRef bead arrays) looking for possible mechanisms and new candidates contributing to the consequences of a single dose of MDMA (15 mg/kg) 3 weeks earlier.

RESULTS

The number of differentially expressed genes in the hippocampus, frontal cortex and the dorsal raphe were 481, 155, and 15, respectively. Gene set enrichment analysis of the microarray data revealed reduced expression of 'memory' and 'cognition', 'dendrite development' and 'regulation of synaptic plasticity' gene sets in the hippocampus, parallel to the downregulation of CaMK II subunits, glutamate-, CB1 cannabinoid- and EphA4, EphA5, EphA6 receptors. Downregulated gene sets in the frontal cortex were related to protein synthesis, chromatin organization, transmembrane transport processes, while 'dendrite development', 'regulation of synaptic plasticity' and 'positive regulation of synapse assembly' gene sets were upregulated besides elevated levels of a CaMK II subunit and NMDA2B glutamate receptor. Changes in the dorsal raphe region were mild and in most cases not significant.

CONCLUSION

The present data raise the possibility of new synapse formation / synaptic reorganization in the frontal cortex 3 weeks after a single neurotoxic dose of MDMA. In contrast, a prolonged depression of new neurite formation in the hippocampus is proposed by downregulations of members in long-term potentiation pathway and synaptic plasticity emphasizing the particular vulnerability of this brain region and proposing a mechanism responsible for cognitive problems in healthy individuals. At the same time, these results underpin benefits of MDMA in PTSD, where the drug may help memory extinction.

Positive psychology in the investigation of psychedelics and entactogens: A critical review

RATIONALE

We reviewed the concepts and empirical findings in studies with psychedelics and entactogens related to positive psychology - the study of healthy human functioning, well-being and eudaemonia. It is an unresolved question how beneficial effects of psychedelics and entactogens are related to the potential risks of these substances - particularly in non-clinical settings.

METHODS

We searched in PubMed, PsychINFO and the Cochrane Library for controlled clinical and epidemiological studies which applied concepts from positive psychology. We included N = 77 eligible studies with 9876 participants published before November 1st, 2017: (1) quantitative studies (N = 54), (2) preliminary or exploratory studies and reviews not including meta-analyses (N = 17), and (3) studies evidencing primarily negative results (N = 6).

RESULTS

Positive psychology concepts have been applied for measuring effects of clinical trials, recreational and ceremonial use of psychedelics and entactogens. Psychedelics and entactogens were shown to produce acute and long-term effects on mood, well-being, prosocial behaviours, empathy, cognitive flexibility, creativity, personality factors like openness, value orientations, nature-relatedness, spirituality, self-transcendence and mindfulness-related capabilities.

CONCLUSIONS

There is preliminary evidence for beneficial effects of psychedelics and entactogens on measures of positive psychology in clinical and healthy populations, however their sustainability remains largely unresolved. The reported results must be considered preliminary due to methodological restrictions. Since longitudinal data on both positive and adverse effects of psychedelics are lacking, more rigorous and standardized measures from positive psychology should be applied in less biased populations with prospective longitudinal designs to carefully assess the benefit-risk-ratio. This article is part of the Special Issue entitled 'Psychedelics: New Doors, Altered Perceptions'.

Discrete memory impairments in largely pure chronic users of MDMA

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 (d_primary=.90, d_polydrug=1.21), followed by working memory (d_primary=.52, d_polydrug=.96), executive functions (d_primary=.46, d_polydrug=.86), and attention (d_primary=.23, d_polydrug=.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.

Updating of working memory in ecstasy polydrug users: Findings from fNIRS

AIMS/OBJECTIVES

Cognitive deficits are now well documented in ecstasy (MDMA) users with type and relative demand of task emerging as important factors. The updating component of executive processes appears to be particularly affected. The study reported here used functional near infrared spectroscopy imaging to investigate changes in cortical haemodynamics during memory updating.

METHOD

Twenty ecstasy users and 20 non-users completed verbal and spatial memory updating tasks and brain blood oxygenation and deoxygenation change was measured using functional near infrared spectroscopy.

RESULTS

There was no interaction between group and difficulty on the updating tasks, though there was a significant main effect of difficulty on both tasks. The effects of group approached significance on the verbal updating task. There were significant differences in blood oxygenation and deoxygenation change at optodes centred over the right and left dorsolateral prefrontal cortex, with ecstasy users showing greater blood oxygenation than the other groups.

DISCUSSION

The lack of a behavioural difference on both tasks but presence of blood oxygenation and deoxygenation changes in letter updating provides support for the notion that ecstasy-polydrug users are investing more effort to achieve the same behavioural output. Total lifetime dose was high, and recency of use was significantly related to most changes, suggesting that heavy and recent use may be particularly detrimental.

Decision-making in chronic ecstasy users: a systematic review

Different cognitive impairments have been reported as a result of long-term MDMA/ecstasy use. Increased impulsivity and altered decision-making have been shown to be associated with the development and maintenance of addictive disorders pointing toward the necessity to understand a potential impairment of decision-making due to MDMA use. Thus, assessing the long-term effects of MDMA is crucial in order to evaluate its controversially discussed therapeutic use. The aim of this systematic review was to summarize the scientific literature on potential effects of chronic MDMA use on higher order decision-making processes in humans. Therefore, a systematic search for controlled trials relevant to the topic has been performed. Only studies using specific tasks on decision-making were included that involved subjects in the drug-free interval with drug-naïve, and/or polydrug control groups. A total of 12 studies could be identified that met the inclusion criteria, all of which were cross-sectional studies. The findings on decision-making disturbances in MDMA users were heterogeneous. Seven studies reported increased risky decisions, whereas five studies did not find MDMA-specific influences on decision-making. Increased impulsivity was observed both in MDMA groups and in (poly)drug control groups in almost all studies. Thus, the current state of research does not allow for the conclusion that long-term use of MDMA affects decision-making behavior in general. More detailed specifications as well as further investigations of the relevant processes are needed. Significant tendencies toward risky decision-making among long-term MDMA use have been observed, but need to be confirmed by studies using a longitudinal design.