OPEN Foundation

Neuroscience

5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) used in a naturalistic group setting is associated with unintended improvements in depression and anxiety

Abstract

BACKGROUND:

A recent epidemiological study suggested that 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) used for spiritual and recreational reasons is associated with subjective improvement in depression and anxiety. Further exploration of the potential psychotherapeutic effects of 5-MeO-DMT could inform future clinical trials.

OBJECTIVES:

We examined self-reported improvement in depression and anxiety among people who use 5-MeO-DMT in a group setting with structured procedures guiding dose and administration of 5-MeO-DMT. Such procedures also include activities for the preparation of, and support during/following sessions, which are similar to procedures used in clinical trials of hallucinogen administration. Next, we examined whether depression or anxiety were improved following use, and whether the acute subjective effects (mystical/challenging) or beliefs about the 5-MeO-DMT experience were associated with improvements in these conditions.

METHODS:

Respondents (n = 362; Mage = 47.7; Male = 55%; White/Caucasian = 84%) completed an anonymous web-based survey.

RESULTS:

Of those reporting having been diagnosed with depression (41%) or anxiety (48%), most reported these conditions were improved (depression = 80%; anxiety = 79%) following 5-MeO-DMT use, and fewer reported they were unchanged (depression = 17%; anxiety = 19%) or worsened (depression = 3%; anxiety = 2%). Improvement in depression/anxiety conditions were associated with greater intensity of mystical experiences and higher ratings of the spiritual significance and personal meaning of the 5-MeO-DMT experience. There were no associations between depression or anxiety improvement and the intensity of acute challenging physical/psychological effects during the 5-MeO-DMT experience.

CONCLUSIONS:

Future prospective controlled clinical pharmacology studies should examine the safety and efficacy of 5-MeO-DMT administration for relieving depression and anxiety.

Davis, A. K., So, S., Lancelotta, R., Barsuglia, J. P., & Griffiths, R. R. (2018). 5-methoxy-N, N-dimethyltryptamine (5-MeO-DMT) used in a naturalistic group setting is associated with unintended improvements in depression and anxiety. The American journal of drug and alcohol abuse, 1-9., 10.1080/00952990.2018.1545024
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Recreational use of psychedelics is associated with elevated personality trait openness: Exploration of associations with brain serotonin markers

Abstract

BACKGROUND:

Recent studies have suggested therapeutic benefits of psychedelics for a variety of mental health conditions. The understanding of how single psychedelic administrations can induce long-lasting effects are, in large, still lacking. However, recent studies in both healthy and clinical populations suggest a role for personality changes.

AIM:

To test support for some of these plausible mechanisms we evaluated (cross-sectional) associations between recreational use of psychedelics and 3,4-methylene-dioxymethamphetamine (MDMA) and (a) personality measures and (b) key markers of cerebral serotonergic signalling (serotonin transporter and serotonin-2A-receptor binding).

METHODS:

In 10 psychedelic-preferring recreational users, 14 MDMA-preferring users and 21 non-using controls, personality was assessed using the ‘big five’ instrument Revised NEO Personality Inventory (NEO-PI-R). Frontal serotonin transporter and serotonin-2A-receptor binding potentials were quantified using [11C]DASB and [18F]altanserin positron emission tomography, respectively.

RESULTS:

Of the five NEO-PI-R traits, only openness to experience scores differed between the three groups; psychedelic-preferring recreational users showing higher openness to experience scores when compared with both MDMA-preferring users and controls. Openness to experience scores were positively associated with lifetime number of psychedelic exposures, and among all MDMA-preferring user/psychedelic-preferring recreational user individuals, frontal serotonin transporter binding – but not frontal serotonin-2A-receptor binding – was positively associated with openness to experience.

CONCLUSION:

Our findings from this cross-sectional study support increasing evidence of a positive association between psychedelic experiences and openness to experience, and (a) expands this to the context of ‘recreational’ psychedelics use, and (b) links serotonergic neurotransmission to openness to experience. A modulation of personality induced by psychedelic experiences may have important therapeutic implications via its impact on peoples’ value systems, cognitive flexibility, and individual and social behaviour.

Erritzoe, D., Smith, J., Fisher, P. M., Carhart-Harris, R., Frokjaer, V. G., & Knudsen, G. M. (2019). Recreational use of psychedelics is associated with elevated personality trait openness: Exploration of associations with brain serotonin markers. Journal of Psychopharmacology., 10.1177/0269881119827891
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Sub-Acute Effects of Psilocybin on Empathy, Creative Thinking, and Subjective Well-Being

Abstract

Creative thinking and empathy are crucial for everyday interactions and subjective well-being. This is emphasized by studies showing a reduction in these skills in populations where social interaction and subjective well-being are significantly compromised (e.g., depression). Anecdotal reports and recent studies suggest that a single administration of psilocybin can enhance such processes and could therefore be a potential treatment. However, it has yet to be assessed whether effects outlast acute intoxication. The present study aimed to assess the sub-acute effects of psilocybin on creative thinking, empathy, and well-being. Participants attending a psilocybin retreat completed tests of creative (convergent and divergent) thinking and empathy, and the satisfaction with life scale on three occasions: before ingesting psilocybin (N = 55), the morning after (N = 50), and seven days after (N = 22). Results indicated that psilocybin enhanced divergent thinking and emotional empathy the morning after use. Enhancements in convergent thinking, valence-specific emotional empathy, and well-being persisted seven days after use. Sub-acute changes in empathy correlated with changes in well-being. The study demonstrates that a single administration of psilocybin in a social setting may be associated with sub-acute enhancement of creative thinking, empathy, and subjective well-being. Future research should test whether these effects contribute to the therapeutic effects in clinical populations.

Mason, N. L., Mischler, E., Uthaug, M. V., & Kuypers, K. P. (2019). Sub-Acute Effects of Psilocybin on Empathy, Creative Thinking, and Subjective Well-Being. Journal of psychoactive drugs, 1-12., 10.1080/02791072.2019.1580804
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Investigation of medical effect of multiple ketamine infusions on patients with major depressive disorder

Abstract

OBJECTIVE::

Single-dose intravenous ketamine has rapid but time-limited antidepressant effects. We aimed to examine the sustained effects of six consecutive ketamine infusions in Chinese patients with major depressive disorder.

METHODS::

Seventy-seven patients with major depressive disorder were eligible to receive augmentation with six ketamine infusions (0.5 mg/kg over 40 min) administered over the course of 12 days (Monday-Wednesday-Friday). The coprimary outcome measures were the rates of response and remission as measured on the 10-item Montgomery-Asberg Depression Rating Scale. Psychotomimetic and dissociative symptoms were measured with the Brief Psychiatric Rating Scale-positive symptoms and the Clinician Administered Dissociative States Scale, respectively.

RESULTS::

After the first ketamine infusion, only 10 (13.0%) and 6 (7.8%) patients responded and remitted, respectively; after six ketamine infusions, 52 (67.5%) patients responded and 37 (48.1%) remitted. There was a significant mean decrease in Montgomery-Asberg Depression Rating Scale score at four hours after the first ketamine infusion (7.0±7.5, p<0.001), and this decrease was maintained for the duration of the infusion period. The response to ketamine treatment was positively associated with no history of psychiatric hospitalization (odds ratio=3.56, p=0.009). Suicidal ideation rapidly decreased across the entire study sample, even among the nonresponder group. No significant differences were found regarding Brief Psychiatric Rating Scale and Clinician Administered Dissociative States Scale scores from the first infusion at baseline to four hours post-infusion.

CONCLUSION::

Six ketamine infusions increased rates of response and remission when compared to a single-dose ketamine infusion in patients with major depressive disorder. Future controlled studies are warranted to confirm and expand these findings.

Zheng, W., Zhou, Y. L., Liu, W. J., Wang, C. Y., Zhan, Y. N., Li, H. Q., … & Ning, Y. P. (2019). Investigation of medical effect of multiple ketamine infusions on patients with major depressive disorder. Journal of Psychopharmacology, 0269881119827811., 10.1177/0269881119827811
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Effective connectivity changes in LSD-induced altered states of consciousness in humans

Abstract

Psychedelics exert unique effects on human consciousness. The thalamic filter model suggests that core effects of psychedelics may result from gating deficits, based on a disintegration of information processing within cortico–striato–thalamo-cortical (CSTC) feedback loops. To test this hypothesis, we characterized changes in directed (effective) connectivity between selected CTSC regions after acute administration of lysergic acid diethylamide (LSD), and after pretreatment with Ketanserin (a selective serotonin 2A receptor antagonist) plus LSD in a double-blind, randomized, placebo-controlled, cross-over study in 25 healthy participants. We used spectral dynamic causal modeling (DCM) for resting-state fMRI data. Fully connected DCM models were specified for each treatment condition to investigate the connectivity between the following areas: thalamus, ventral striatum, posterior cingulate cortex, and temporal cortex. Our results confirm major predictions proposed in the CSTC model and provide evidence that LSD alters effective connectivity within CSTC pathways that have been implicated in the gating of sensory and sensorimotor information to the cortex. In particular, LSD increased effective connectivity from the thalamus to the posterior cingulate cortex in a way that depended on serotonin 2A receptor activation, and decreased effective connectivity from the ventral striatum to the thalamus independently of serotonin 2A receptor activation. Together, these results advance our mechanistic understanding of the action of psychedelics in health and disease. This is important for the development of new pharmacological therapeutics and also increases our understanding of the mechanisms underlying the potential clinical efficacy of psychedelics.

Preller, K. H., Razi, A., Zeidman, P., Stämpfli, P., Friston, K. J., & Vollenweider, F. X. (2019). Effective connectivity changes in LSD-induced altered states of consciousness in humans. Proceedings of the National Academy of Sciences, 201815129., 10.1073/pnas.1815129116
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Psychedelic medicine: The biology underlying the persisting psychedelic effects.

Abstract

Psychedelic substances have regained interest as therapeutic agents in the treatment of stress-related disorders. The effects seem to be of persisting nature even after a single dose. Also in lower than ‘regular’ recreational doses, so-called micro-doses, without the typical effects on consciousness, users report beneficial effects on cognitive processes and well-being. The exact neurobiological mechanism underlying these persisting effects is not clear. While previous research has mainly focused on the central nervous system including the immune system and the neuroendocrine system, I propose a central role for sleep and the microbiome in the effects of regular and low doses of psychedelics respectively. It will be explained why this is hypothesized and studies to test this idea proposed. It is concluded that while these studies are needed to understand the biology underlying psychedelic medicine, it is also important to approach it in a holistic way, including all the above mentioned biological processes psychedelics are known to affect, and explore the role of other substance-related factors like route of administration and form, and factors like diet and lifestyle which are part of the psychedelic experience.

Kuypers, K. P. C. (2019). Psychedelic medicine: The biology underlying the persisting psychedelic effects. Medical hypotheses125, 21-24., https://doi.org/10.1016/j.mehy.2019.02.029
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A systematic study of microdosing psychedelics

Abstract

The phenomenon of ‘microdosing’, that is, regular ingestion of very small quantities of psychedelic substances, has seen a rapid explosion of popularity in recent years. Individuals who microdose report minimal acute effects from these substances yet claim a range of long-term general health and wellbeing benefits. There have been no published empirical studies of microdosing and the current legal and bureaucratic climate makes direct empirical investigation of the effects of psychedelics difficult. In Study One we conducted a systematic, observational investigation of individuals who microdose. We tracked the experiences of 98 microdosing participants, who provided daily ratings of psychological functioning over a six week period. 63 of these additionally completed a battery of psychometric measures tapping mood, attention, wellbeing, mystical experiences, personality, creativity, and sense of agency, at baseline and at completion of the study. Analyses of daily ratings revealed a general increase in reported psychological functioning across all measures on dosing days but limited evidence of residual effects on following days. Analyses of pre and post study measures revealed reductions in reported levels of depression and stress; lower levels of distractibility; increased absorption; and increased neuroticism. To better understand these findings, in Study Two we investigated pre-existing beliefs and expectations about the effects of microdosing in a sample of 263 naïve and experienced microdosers, so as to gauge expectancy bias. All participants believed that microdosing would have large and wide-ranging benefits in contrast to the limited outcomes reported by actual microdosers. Notably, the effects believed most likely to change were unrelated to the observed pattern of reported outcomes. The current results suggest that dose controlled empirical research on the impacts of microdosing on mental health and attentional capabilities are needed.

Polito, V., & Stevenson, R. J. (2019). A systematic study of microdosing psychedelics. PloS one14(2), e0211023., 10.1371/journal.pone.0211023.
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Psychedelic effects of psilocybin correlate with serotonin 2A receptor occupancy and plasma psilocin levels.

Abstract

The main psychedelic component of magic mushrooms is psilocybin, which shows promise as a treatment for depression and other mental disorders. Psychedelic effects are believed to emerge through stimulation of serotonin 2A receptors (5-HT2ARs) by psilocybin’s active metabolite, psilocin. We here report for the first time the relationship between intensity of psychedelic effects, cerebral 5-HT2AR occupancy and plasma levels of psilocin in humans. Eight healthy volunteers underwent positron emission tomography (PET) scans with the 5-HT2AR agonist radioligand [11C]Cimbi-36: one at baseline and one or two additional scans on the same day after a single oral intake of psilocybin (3-30 mg). 5-HT2AR occupancy was calculated as the percent change in cerebral 5-HT2AR binding relative to baseline. Subjective psychedelic intensity and plasma psilocin levels were measured during the scans. Relations between subjective intensity, 5-HT2AR occupancy, and plasma psilocin levels were modeled using non-linear regression. Psilocybin intake resulted in dose-related 5-HT2AR occupancies up to 72%; plasma psilocin levels and 5-HT2AR occupancy conformed to a single-site binding model. Subjective intensity was correlated with both 5-HT2AR occupancy and psilocin levels as well as questionnaire scores. We report for the first time that intake of psilocybin leads to significant 5-HT2AR occupancy in the human brain, and that both psilocin plasma levels and 5-HT2AR occupancy are closely associated with subjective intensity ratings, strongly supporting that stimulation of 5-HT2AR is a key determinant for the psychedelic experience. Important for clinical studies, psilocin time-concentration curves varied but psilocin levels were closely associated with psychedelic experience.
Madsen, M. K., Fisher, P. M., Burmester, D., Dyssegaard, A., Stenbæk, D. S., Kristiansen, S., … & Erritzoe, D. (2019). Psychedelic effects of psilocybin correlate with serotonin 2A receptor occupancy and plasma psilocin levels. Neuropsychopharmacology, 1., 10.1038/s41386-019-0324-9
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Effects of acute and repeated treatment with serotonin 5-HT2A receptor agonist hallucinogens on intracranial self-stimulation in rats

Abstract

The prototype 5-HT2A receptor agonist hallucinogens LSD, mescaline, and psilocybin are classified as Schedule 1 drugs of abuse by the U.S. Drug Enforcement Administration. Accumulating clinical evidence has also suggested that acute or repeated “microdosing” with these drugs may have utility for treatment of some mental health disorders, including drug abuse and depression. The goal of the present study was to evaluate LSD, mescaline, and psilocybin effects on intracranial self-stimulation (ICSS), a procedure that has been used to evaluate abuse-related effects of other classes of abused drugs. Effects of repeated LSD were also examined to evaluate potential changes in its own effects on ICSS or changes in effects produced by the abused psychostimulant methamphetamine or the prodepressant kappa opioid receptor (KOR) agonist U69,593. Male Sprague-Dawley rats were implanted with microelectrodes targeting the medial forebrain bundle and trained to respond under a “frequency-rate” ICSS procedure, in which many drugs of abuse increase (or “facilitate”) ICSS. In acute dose-effect and time-course studies, evidence for abuse-related ICSS facilitation was weak and inconsistent; the predominant effect of all 3 drugs was dose- and time-dependent ICSS depression. Repeated LSD treatment failed to alter either its own ICSS depressant effects or the abuse-related effects of methamphetamine; however, repeated LSD did attenuate ICSS depression by U69,593. These results extend those of previous preclinical studies to suggest weak expression of abuse-related effects by 5-HT2A agonist hallucinogens and provide supportive evidence for therapeutic effects of repeated LSD dosing to attenuate KOR-mediated depressant effects but not abuse potential of psychostimulants.

Sakloth, F., Leggett, E., Moerke, M. J., Townsend, E. A., Banks, M. L., & Negus, S. S. (2019). Effects of acute and repeated treatment with serotonin 5-HT2A receptor agonist hallucinogens on intracranial self-stimulation in rats. Experimental and clinical psychopharmacology., 10.1037/pha0000253.
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Association of Combined Naltrexone and Ketamine With Depressive Symptoms in a Case series of Patients With Depression and Alcohol Use Disorder

Abstract

Ketamine has rapid and robust antidepressant effects. However, there are concerns about the abuse liability of ketamine. This concern was heightened recently owing to a preliminary report suggesting that antidepressant effects of ketamine might be dependent on opiate receptor stimulation. Below, we present pilot data that indicate that the antidepressant effects of ketamine are not attenuated by naltrexone pretreatment. As a result, the combination of opiate receptor antagonism with ketamine might be a strategy to reduce addiction risk among patients with depression at risk for substance abuse.

Yoon, G., Petrakis, I. L., & Krystal, J. H. (2019). Association of Combined Naltrexone and Ketamine With Depressive Symptoms in a Case series of Patients With Depression and Alcohol Use Disorder. JAMA psychiatry., 10.1001/jamapsychiatry.2018.3990.
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