OPEN Foundation

S. Borgwardt

MDMA-induced changes in within-network connectivity contradict the specificity of these alterations for the effects of serotonergic hallucinogens

Abstract

It has been reported that serotonergic hallucinogens like lysergic acid diethylamide (LSD) induce decreases in functional connectivity within various resting-state networks. These alterations were seen as reflecting specific neuronal effects of hallucinogens and it was speculated that these shifts in connectivity underlie the characteristic subjective drug effects. In this study, we test the hypothesis that these alterations are not specific for hallucinogens but that they can be induced by monoaminergic stimulation using the non-hallucinogenic serotonin-norepinephrine-dopamine releasing agent 3,4-methylenedioxymethamphetamine (MDMA). In a randomized, placebo-controlled, double-blind, crossover design, 45 healthy participants underwent functional magnetic resonance imaging (fMRI) following oral administration of 125 mg MDMA. The networks under question were identified using independent component analysis (ICA) and were tested with regard to within-network connectivity. Results revealed decreased connectivity within two visual networks, the default mode network (DMN), and the sensorimotor network. These findings were almost identical to the results previously reported for hallucinogenic drugs. Therefore, our results suggest that monoaminergic substances can induce widespread changes in within-network connectivity in the absence of marked subjective drug effects. This contradicts the notion that these alterations can be regarded as specific for serotonergic hallucinogens. However, changes within the DMN might explain antidepressants effects of some of these substances.

Müller, F., Holze, F., Dolder, P., Ley, L., Vizeli, P., Soltermann, A., Liechti, M. E., & Borgwardt, S. (2021). MDMA-induced changes in within-network connectivity contradict the specificity of these alterations for the effects of serotonergic hallucinogens. Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 46(3), 545–553. https://doi.org/10.1038/s41386-020-00906-2

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Acute dose-dependent effects of lysergic acid diethylamide in a double-blind placebo-controlled study in healthy subjects

Abstract

Growing interest has been seen in using lysergic acid diethylamide (LSD) in psychiatric research and therapy. However, no modern studies have evaluated subjective and autonomic effects of different and pharmaceutically well-defined doses of LSD. We used a double-blind, randomized, placebo-controlled, crossover design in 16 healthy subjects (eight women, eight men) who underwent six 25 h sessions and received placebo, LSD (25, 50, 100, and 200 µg), and 200 µg LSD 1 h after administration of the serotonin 5-hydroxytryptamine-2A (5-HT2A) receptor antagonist ketanserin (40 mg). Test days were separated by at least 10 days. Outcome measures included self-rating scales that evaluated subjective effects, autonomic effects, adverse effects, plasma brain-derived neurotrophic factor levels, and pharmacokinetics up to 24 h. The pharmacokinetic-subjective response relationship was evaluated. LSD showed dose-proportional pharmacokinetics and first-order elimination and dose-dependently induced subjective responses starting at the 25 µg dose. A ceiling effect was observed for good drug effects at 100 µg. The 200 µg dose of LSD induced greater ego dissolution than the 100 µg dose and induced significant anxiety. The average duration of subjective effects increased from 6.7 to 11 h with increasing doses of 25-200 µg. LSD moderately increased blood pressure and heart rate. Ketanserin effectively prevented the response to 200 µg LSD. The LSD dose-response curve showed a ceiling effect for subjective good effects, and ego dissolution and anxiety increased further at a dose above 100 µg. These results may assist with dose finding for future LSD research. The full psychedelic effects of LSD are primarily mediated by serotonin 5-HT2A receptor activation.

Holze, F., Vizeli, P., Ley, L., Müller, F., Dolder, P., Stocker, M., Duthaler, U., Varghese, N., Eckert, A., Borgwardt, S., & Liechti, M. E. (2021). Acute dose-dependent effects of lysergic acid diethylamide in a double-blind placebo-controlled study in healthy subjects. Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 46(3), 537–544. https://doi.org/10.1038/s41386-020-00883-6

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Acute effects of lysergic acid diethylamide (LSD) on resting brain function.

Abstract

Lysergic acid diethylamide (LSD) is a potent hallucinogenic substance that was extensively investigated by psychiatrists during the 1950s and 1960s. Researchers were interested in the unique effects induced by this substance, some of which resemble symptoms seen in schizophrenia. Moreover, during that period LSD was studied and used for the treatment of several mental disorders such as depression, anxiety, addiction and personality disorders. Despite this long history of research, how LSD induces its specific effects on a neuronal level has been relatively unclear. In recent years there has been a revival of research in hallucinogenic drugs and their possible clinical applications. These contemporary studies in the UK and Switzerland include neuroimaging studies using functional magnetic resonance imaging (fMRI). In this review, we collect and interpret these recent neuroimaging findings. Overall, previous results across studies indicate that LSD administration is associated with extensive alterations in functional brain connectivity, measuring the correlated activities between different brain regions. The studies mostly reported increases in connectivity between regions and, more specifically, consistently found increased connectivity within the thalamocortical system. These latter observations are in agreement with models proposing that hallucinogenic drugs exert their effects by inhibiting cerebral filtering of external and internal data. However, studies also face several limitations, including potential biases of neuroimaging measurements.
Müller, F., & Borgwardt, S. (2019). Acute effects of lysergic acid diethylamide (LSD) on resting brain function. Swiss Medical Weekly149(3940)., https://doi.org/10.4414/smw.2019.20124
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Pharmacokinetics and subjective effects of a novel oral LSD formulation in healthy subjects.

Abstract

AIMS:

The aim of the present study was to characterize the pharmacokinetics and exposure-subjective response relationship of a novel oral solution of lysergic acid diethylamide (LSD) that was developed for clinical use in research and patients.

METHOD:

LSD (100 μg) was administered in 27 healthy subjects using a placebo-controlled, double-blind, cross-over design. Plasma levels of LSD, nor-LSD, and 2-oxo-3-hydroxy-LSD (O-H-LSD) and subjective drug effects were assessed up to 11.5 hours.

RESULTS:

First-order elimination kinetics were observed for LSD. Geometric mean maximum concentration (Cmax ) values (range) of 1.7 (1.0-2.9) ng/mL were reached at a tmax (range) of 1.7 (1.0-3.4) hours after drug administration. The plasma half-life (t1/2 ) was 3.6 (2.4-7.3) hours. The AUC was 13 (7.1-28) ng·h/mL. No differences in these pharmacokinetic parameters were found between male and female subjects. Plasma O-H-LSD but not nor-LSD (< 0.01 ng/mL) concentrations could be quantified in all subjects. Geometric mean O-H-LSD Cmax values (range) of 0.11 (0.07-0.19) ng/mL were reached at a tmax (range) of 5 (3.2-8) hours. The t1/2 and AUC values of O-H-LSD were 5.2 (2.6-21) hours and 1.7 (0.85-4.3) ng·h/mL, respectively. The subjective effects of LSD lasted (mean ± SD) for 8.5 ± 2.0 hours (range: 5.3-12.8 h), and peak effects were reached 2.5 ± 0.6 hours (range 1.6-4.3 h) after drug administration. EC50 values were 1.0 ± 0.5 ng/mL and 1.9 ± 1.0 ng/mL for “good” and “bad” subjective drug effects, respectively.

CONCLUSION:

The present study characterized the pharmacokinetics of LSD and its main metabolite O-H-LSD. The subjective effects of LSD were closely associated with changes in plasma concentrations over time.

Holze, F., Duthaler, U., Vizeli, P., Müller, F., Borgwardt, S., & Liechti, M. E. (2019). Pharmacokinetics and subjective effects of a novel oral LSD formulation in healthy subjects. British journal of clinical pharmacology., 10.1111/bcp.13918
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Neuroimaging of chronic MDMA (“ecstasy”) effects: A meta-analysis

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

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.

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 research242, 159-177. 10.1016/bs.pbr.2018.08.004
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Altered network hub connectivity after acute LSD administration

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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Acute LSD effects on response inhibition neural networks

Abstract

BACKGROUND:
Recent evidence shows that the serotonin 2A receptor (5-hydroxytryptamine2A receptor, 5-HT2AR) is critically involved in the formation of visual hallucinations and cognitive impairments in lysergic acid diethylamide (LSD)-induced states and neuropsychiatric diseases. However, the interaction between 5-HT2AR activation, cognitive impairments and visual hallucinations is still poorly understood. This study explored the effect of 5-HT2AR activation on response inhibition neural networks in healthy subjects by using LSD and further tested whether brain activation during response inhibition under LSD exposure was related to LSD-induced visual hallucinations.
METHODS:
In a double-blind, randomized, placebo-controlled, cross-over study, LSD (100 µg) and placebo were administered to 18 healthy subjects. Response inhibition was assessed using a functional magnetic resonance imaging Go/No-Go task. LSD-induced visual hallucinations were measured using the 5 Dimensions of Altered States of Consciousness (5D-ASC) questionnaire.
RESULTS:
Relative to placebo, LSD administration impaired inhibitory performance and reduced brain activation in the right middle temporal gyrus, superior/middle/inferior frontal gyrus and anterior cingulate cortex and in the left superior frontal and postcentral gyrus and cerebellum. Parahippocampal activation during response inhibition was differently related to inhibitory performance after placebo and LSD administration. Finally, activation in the left superior frontal gyrus under LSD exposure was negatively related to LSD-induced cognitive impairments and visual imagery.
CONCLUSION:
Our findings show that 5-HT2AR activation by LSD leads to a hippocampal-prefrontal cortex-mediated breakdown of inhibitory processing, which might subsequently promote the formation of LSD-induced visual imageries. These findings help to better understand the neuropsychopharmacological mechanisms of visual hallucinations in LSD-induced states and neuropsychiatric disorders.
Schmidt, A., Müller, F., Lenz, C., Dolder, P. C., Schmid, Y., Zanchi, D., … & Borgwardt, S. (2017). Acute LSD effects on response inhibition neural networks. Psychological Medicine, 1-13. 10.1017/S0033291717002914
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Increased thalamic resting-state connectivity as a core driver of LSD-induced hallucinations

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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22 May - Delivering Effective Psychedelic Clinical Trials

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