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M. Liechti

Neuroimaging of chronic MDMA ("ecstasy") effects: A meta-analysis

November 12, 2018 / MDMA, Neuroscience, Papers, Publications / By / , , ,

Abstract

In this meta-analysis, we aimed to assess the evidence from neuroimaging studies for chronic alterations in the brains of MDMA users. The databases PubMed, Embase, and Web of Science were searched for studies published from inception to August 24, 2018, without any language restriction. Sixteen independent studies comprising 356 MDMA users and 311 controls were included. Of these, five studies investigated frontal and occipital N-acetylaspartate/creatine and myo-inositol/creatine ratios, three studies assessed basal ganglia blood flow and ten studies investigated serotonin transporter (SERT) density in various regions. We found significantly decreased SERT density in eight of 13 investigated regions. Meta-regression indicated a positive association with abstinence, but none with lifetime episodes of use. Therefore, other variables (such as doses taken per occasion) might be more important determinants. Positive associations between time of abstinence and SERT density might indicate that these alterations are reversible to some extent. Furthermore, there were no significant differences between user and control groups in terms of neurochemical ratios in the frontal and occipital lobes and blood flow in the basal ganglia. Overall, MDMA user groups showed heavy use patterns and study quality was poor.

Müller, F., Brändle, R., Liechti, M. E., & Borgwardt, S. (2018). Neuroimaging of chronic MDMA (“ecstasy”) effects: A meta-analysis of the literature. Neuroscience & Biobehavioral Reviews., 10.1016/j.neubiorev.2018.11.004
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Neuroimaging of chronic MDMA (“ecstasy”) effects: A meta-analysis

November 12, 2018 / MDMA, Neuroscience, Papers, Publications / By / , , ,

Abstract

In this meta-analysis, we aimed to assess the evidence from neuroimaging studies for chronic alterations in the brains of MDMA users. The databases PubMed, Embase, and Web of Science were searched for studies published from inception to August 24, 2018, without any language restriction. Sixteen independent studies comprising 356 MDMA users and 311 controls were included. Of these, five studies investigated frontal and occipital N-acetylaspartate/creatine and myo-inositol/creatine ratios, three studies assessed basal ganglia blood flow and ten studies investigated serotonin transporter (SERT) density in various regions. We found significantly decreased SERT density in eight of 13 investigated regions. Meta-regression indicated a positive association with abstinence, but none with lifetime episodes of use. Therefore, other variables (such as doses taken per occasion) might be more important determinants. Positive associations between time of abstinence and SERT density might indicate that these alterations are reversible to some extent. Furthermore, there were no significant differences between user and control groups in terms of neurochemical ratios in the frontal and occipital lobes and blood flow in the basal ganglia. Overall, MDMA user groups showed heavy use patterns and study quality was poor.

Müller, F., Brändle, R., Liechti, M. E., & Borgwardt, S. (2018). Neuroimaging of chronic MDMA (“ecstasy”) effects: A meta-analysis of the literature. Neuroscience & Biobehavioral Reviews., 10.1016/j.neubiorev.2018.11.004
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Advances and challenges in neuroimaging studies on the effects of serotonergic hallucinogens: Contributions of the resting brain.

September 28, 2018 / Ayahuasca, LSD, Mushrooms / Psilocybin, Neuroscience, Papers, Psychology, Publications / By / , , , , , ,

Abstract

The effects of hallucinogenic drugs on the human brain have been studied since the earliest days of neuroimaging in the 1990s. However, approaches are often hard to compare and results are heterogeneous. In this chapter, we summarize studies investigating the effects of hallucinogens on the resting brain, with a special emphasis on replicability and limitations. In previous studies, similarities were observed between psilocybin, LSD, and ayahuasca, with respect to decreases in cerebral blood flow and increases in global functional connectivity in the precuneus and thalamus. Additionally, LSD consistently decreased functional connectivity within distinct resting state networks. Little convergence was observed for connectivity between networks and for blood flow in other brain regions. Although these studies are limited by small sample sizes and might be biased by unspecific drug effects on physiological parameters and the vascular system, current results indicate that neuroimaging could be a useful tool to elucidate the neuronal correlates of hallucinogenic effects.
Müller, F., Liechti, M. E., Lang, U. E., Borgwardt, S., Wilson, M. R., Webb, A., … & Lutz, K. (2018). Advances and challenges in neuroimaging studies on the effects of serotonergic hallucinogens: Contributions of the resting brain. Progress in brain research, 242, 159-177. 10.1016/bs.pbr.2018.08.004
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Oxytocin receptor gene variations and socio-emotional effects of MDMA: A pooled analysis of controlled studies in healthy subjects

June 18, 2018 / MDMA, Neuroscience, Papers, Psychology, Publications / By / ,

Abstract

Methylenedioxymethamphetamine (MDMA) increases oxytocin, empathy, and prosociality. Oxytocin plays a critical role in emotion processing and social behavior and has been shown to mediate the prosocial effects of MDMA in animals. Genetic variants, such as single-nucleotide polymorphisms (SNPs), of the oxytocin receptor (OXTR) may influence the emotional and social effects of MDMA in humans. The effects of common genetic variants of the OXTR (rs53576, rs1042778, and rs2254298 SNPs) on the emotional, empathogenic, and prosocial effects of MDMA were characterized in up to 132 healthy subjects in a pooled analysis of eight double-blind, placebo-controlled studies. In a subset of 53 subjects, MDMA produced significantly greater feelings of trust in rs1042778 TT genotypes compared with G allele carriers. The rs53576 and rs225498 SNPs did not moderate the subjective effects of MDMA in up to 132 subjects. None of the SNPs moderated MDMA-induced impairments in negative facial emotion recognition or enhancements in emotional empathy in the Multifaceted Empathy Test in 69 subjects. MDMA significantly increased plasma oxytocin concentrations. MDMA and oxytocin concentrations did not differ between OXTR gene variants. The present results provide preliminary evidence that OXTR gene variations may modulate aspects of the prosocial subjective effects of MDMA in humans. However, interpretation should be cautious due to the small sample size. Additionally, OXTR SNPs did not moderate the subjective overall effect of MDMA (any drug effect) or feelings of “closeness to others”.
Vizeli, P., & Liechti, M. E. (2018). Oxytocin receptor gene variations and socio-emotional effects of MDMA: A pooled analysis of controlled studies in healthy subjects. PloS one, 13(6), e0199384. 10.1371/journal.pone.0199384
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Altered network hub connectivity after acute LSD administration

March 7, 2018 / LSD, Neuroscience, Papers, Psychology, Publications / By / , , , ,

Abstract

LSD is an ambiguous substance, said to mimic psychosis and to improve mental health in people suffering from anxiety and depression. Little is known about the neuronal correlates of altered states of consciousness induced by this substance. Limited previous studies indicated profound changes in functional connectivity of resting state networks after the administration of LSD. The current investigation attempts to replicate and extend those findings in an independent sample. In a double-blind, randomized, cross-over study, 100 μg LSD and placebo were orally administered to 20 healthy participants. Resting state brain activity was assessed by functional magnetic resonance imaging. Within-network and between-network connectivity measures of ten established resting state networks were compared between drug conditions. Complementary analysis were conducted using resting state networks as sources in seed-to-voxel analyses. Acute LSD administration significantly decreased functional connectivity within visual, sensorimotor and auditory networks and the default mode network. While between-network connectivity was widely increased and all investigated networks were affected to some extent, seed-to-voxel analyses consistently indicated increased connectivity between networks and subcortical (thalamus, striatum) and cortical (precuneus, anterior cingulate cortex) hub structures. These latter observations are consistent with findings on the importance of hubs in psychopathological states, especially in psychosis, and could underlay therapeutic effects of hallucinogens as proposed by a recent model.
Müller, F., Dolder, P. C., Schmidt, A., Liechti, M. E., & Borgwardt, S. (2018). Altered network hub connectivity after acute LSD administration. NeuroImage: Clinical. 10.1016/j.nicl.2018.03.005
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Increased thalamic resting-state connectivity as a core driver of LSD-induced hallucinations

September 21, 2017 / LSD, Neuroscience, Papers, Publications / By / , , , , , ,

Abstract

OBJECTIVE:
It has been proposed that the thalamocortical system is an important site of action of hallucinogenic drugs and an essential component of the neural correlates of consciousness. Hallucinogenic drugs such as LSD can be used to induce profoundly altered states of consciousness, and it is thus of interest to test the effects of these drugs on this system.
METHOD:
100 μg LSD was administrated orally to 20 healthy participants prior to fMRI assessment. Whole brain thalamic functional connectivity was measured using ROI-to-ROI and ROI-to-voxel approaches. Correlation analyses were used to explore relationships between thalamic connectivity to regions involved in auditory and visual hallucinations and subjective ratings on auditory and visual drug effects.
RESULTS:
LSD caused significant alterations in all dimensions of the 5D-ASC scale and significantly increased thalamic functional connectivity to various cortical regions. Furthermore, LSD-induced functional connectivity measures between the thalamus and the right fusiform gyrus and insula correlated significantly with subjective auditory and visual drug effects.
CONCLUSION:
Hallucinogenic drug effects might be provoked by facilitations of cortical excitability via thalamocortical interactions. Our findings have implications for the understanding of the mechanism of action of hallucinogenic drugs and provide further insight into the role of the 5-HT2A -receptor in altered states of consciousness.
Mueller, F., Lenz, C., Dolder, P., Lang, U., Schmidt, A., Liechti, M., & Borgwardt, S. (2017). Increased thalamic resting‐state connectivity as a core driver of LSD‐induced hallucinations. Acta Psychiatrica Scandinavica. 10.1111/acps.12818
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Long-lasting subjective effects of LSD in normal subjects

September 16, 2017 / LSD, Papers, Psychology / By / ,

Abstract

Rationale

Lysergic acid diethylamide (LSD) and other serotonergic hallucinogens can induce profound alterations of consciousness and mystical-type experiences, with reportedly long-lasting effects on subjective well-being and personality.

Methods

We investigated the lasting effects of a single dose of LSD (200 μg) that was administered in a laboratory setting in 16 healthy participants. The following outcome measures were assessed before and 1 and 12 months after LSD administration: Persisting Effects Questionnaire (PEQ), Mysticism Scale (MS), Death Transcendence Scale (DTS), NEO-Five Factor Inventory (NEO-FFI), and State-Trait Anxiety Inventory (STAI).

Results

On the PEQ, positive attitudes about life and/or self, positive mood changes, altruistic/positive social effects, positive behavioral changes, and well-being/life satisfaction significantly increased at 1 and 12 months and were subjectively attributed by the subjects to the LSD experience. Five-Dimensions of Altered States of Consciousness (5D-ASC) total scores, reflecting acutely induced alterations in consciousness, and Mystical Experience Questionnaire (MEQ30) total scores correlated with changes in well-being/life satisfaction 12 months after LSD administration. No changes in negative attitudes, negative mood, antisocial/negative social effects, or negative behavior were attributed to the LSD experience. After 12 months, 10 of 14 participants rated their LSD experience as among the top 10 most meaningful experiences in their lives. Five participants rated the LSD experience among the five most spiritually meaningful experiences in their lives. On the MS and DTS, ratings of mystical experiences significantly increased 1 and 12 months after LSD administration compared with the pre-LSD screening. No relevant changes in personality measures were found.

Conclusions

In healthy research subjects, the administration of a single dose of LSD (200 μg) in a safe setting was subjectively considered a personally meaningful experience that had long-lasting subjective positive effects.

Schmid, Y., & Liechti, M. E. (2017). Long-lasting subjective effects of LSD in normal subjects. Psychopharmacology, 1-11. 10.1007/s00213-017-4733-3
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First Time View on Human Metabolome Changes after a Single Intake of 3,4-Methylenedioxymethamphetamine in Healthy Placebo-Controlled Subjects

September 1, 2017 / MDMA, Papers, Psychiatry & Medicine, Publications / By / , , , ,

Abstract

3,4-Methylenedioxymethamphetamine (MDMA; “ecstasy”) is widely consumed recreationally. Little is known about its effects on the human metabolome. Mapping biochemical changes after drug exposure can complement traditional approaches by revealing potential biomarkers of organ toxicity or discovering new metabolomic features in a time- and dose-dependent manner. We aimed to analyze for the first time plasma samples from a randomized, double-blind, placebo-controlled crossover study in healthy adults to explore changes in endogenous plasma metabolites following a single intake of MDMA. Plasma samples from 15 subjects taken at four different time points were analyzed with the commercially available AbsoluteIDQ kit (Biocrates). Time series analysis revealed a total of nine metabolites, which showed a significant concentration change after MDMA administration compared with placebo. Paired t tests of the single time points showed statistically significant concentration changes mainly of glycerophospholipids and the metabolic ratio of methionine-sulfoxide over methionine. Changes of this metabolic ratio may be indicative for changes in systemic oxidative stress levels, and the increased amount of glycerophospholipids could be interpreted as an upregulation of energy production. Baseline samples within the experimental study design were crucial for evaluation of metabolomics data as interday individuality within subjects was high otherwise resulting in overestimations of the findings.
Boxler, M. I., Liechti, M. E., Schmid, Y., Kraemer, T., & Steuer, A. E. (2017). First Time View on Human Metabolome Changes after a Single Intake of 3, 4-Methylenedioxymethamphetamine in Healthy Placebo-Controlled Subjects. Journal of proteome research, 16(9), 3310-3320. 10.1021/acs.jproteome.7b00294
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First time view on human metabolome changes after a single intake of 3,4 methylenedioxymethamphetamine (MDMA) in healthy placebo-controlled subjects

July 19, 2017 / MDMA, Papers, Psychiatry & Medicine / By / , , , ,

Abstract

3,4-Methylenedioxymethamphetamine (MDMA; “ecstasy”) is widely consumed recreationally. Little is known about its effects on the human metabolome. Mapping biochemical changes after drug exposure can complement traditional approaches by revealing potential biomarkers of organ toxicity or discovering new metabolomic features in a time- and dose-dependent manner. We aimed to analyze for the first time plasma samples from a randomized, double-blind, placebo-controlled crossover study in healthy adults to explore changes in endogenous plasma metabolites following a single intake of MDMA. Plasma samples from 15 subjects taken at four different time points were analyzed with the commercially available AbsoluteIDQ kit (Biocrates). Time series analysis revealed a total of nine metabolites, which showed a significant concentration change after MDMA administration compared with placebo. Paired t tests of the single time points showed statistically significant concentration changes mainly of glycerophospholipids and the metabolic ratio of methionine-sulfoxide over methionine. Changes of this metabolic ratio may be indicative for changes in systemic oxidative stress levels, and the increased amount of glycerophospholipids could be interpreted as an upregulation of energy production. Baseline samples within the experimental study design were crucial for evaluation of metabolomics data as interday individuality within subjects was high otherwise resulting in overestimations of the findings.
Boxler, M. I., Liechti, M. E., Schmid, Y., Kraemer, T., & Steuer, A. E. (2017). First Time View on Human Metabolome Changes after a Single Intake of 3, 4-Methylenedioxymethamphetamine in Healthy Placebo-Controlled Subjects. Journal of Proteome Research, 16(9), 3310-3320. 10.1021/acs.jproteome.7b00294
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Monoamine receptor interaction profiles of 4-thio-substituted phenethylamines (2C-T drugs)

July 15, 2017 / Neuroscience, Papers / By / , , ,

Abstract

BACKGROUND:
4-Thio-substituted phenethylamines (2C-T drugs) are potent psychedelics with poorly defined pharmacological properties. Because of their psychedelic effects, 2C-T drugs are sometimes sold as new psychoactive substances (NPSs). The aim of the present study was to characterize the monoamine receptor and transporter interaction profiles of a series of 2C-T drugs.
METHODS:
We determined the binding affinities of 2C-T drugs at monoamine receptors and transporters in human cells that were transfected with the respective receptors or transporters. We also investigated the functional activation of serotonergic 5-hydroxytryptamine 2A (5-HT2A) and 5-HT2B receptors, activation of human trace amine-associated receptor 1 (TAAR1), and inhibition of monoamine uptake transporters.
RESULTS:
2C-T drugs had high affinity for 5-HT2A and 5-HT2C receptors (1-54 nM and 40-350 nM, respectively). With activation potencies of 1-53 nM and 44-370 nM, the drugs were potent 5-HT2A receptor and 5-HT2B receptor, respectively, partial agonists. An exception to this were the benzylthiophenethylamines, which did not potently activate the 5-HT2B receptor (EC50 > 3000 nM). Furthermore, the compounds bound to serotonergic 5-HT1A and adrenergic receptors. The compounds had high affinity for the rat TAAR1 (5-68 nM) and interacted with the mouse but not human TAAR1. The 2C-T drugs did not potently interact with monoamine transporters (Ki > 4000 nM).
CONCLUSION:
The receptor binding profile of 2C-T drugs predicts psychedelic effects that are mediated by potent 5-HT2 receptor interactions.
Luethi, D., Trachsel, D., Hoener, M. C., & Liechti, M. E. (2017). Monoamine receptor interaction profiles of 4-thio-substituted phenethylamines (2C-T drugs). Neuropharmacology. 10.1016/j.neuropharm.2017.07.012
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