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DARK Classics in Chemical Neuroscience: Ibogaine.

/ Anxiety Disorders / PTSD, Depressive Disorders, Iboga / Ibogaine, Papers, Psychology, Publications, Substance Use Disorder / / , ,

Abstract

The West African iboga plant has been used for centuries by the Bwiti and Mbiri tribes to induce hallucinations during religious ceremonies. Ibogaine, the principal alkaloid responsible for iboga’s psychedelic properties, was isolated and sold as an antidepressant in France for decades before its adverse effects precipitated its removal from the market. An ibogaine resurgence in the 1960s was driven by U.S. heroin addicts who claimed that ibogaine cured their opiate addictions. Behavioral pharmacologic studies in animal models provided evidence that ibogaine could blunt self-administration of not only opiates but cocaine, amphetamines, and nicotine. Ibogaine displays moderate-to-weak affinities for a wide spectrum of receptor and transporter proteins; recent work suggests that its actions at nicotinic acetylcholine receptor subtypes may underlie its reputed antiopiate effects. At micromolar levels, ibogaine is neurotoxic and cardiotoxic and has been linked to several deaths by cardiac arrest. Structure-activity studies led to the isolation of the ibogaine analog 18-methoxycoronaridine (18-MC), an α3β4 nicotinic receptor modulator that retains ibogaine’s anticraving properties with few or no adverse effects. Clinical trials of 18-MC treatment of nicotine addiction are pending. Ibogaine analogs may also hold promise for treating anxiety and depression via the “psychedelic-assisted therapy” approach that employs hallucinogens including psilocybin and methylenedioxymethamphetamine (“ecstasy”).
Wasko, M. J., Witt-Enderby, P. A., & Surratt, C. K. (2018). DARK Classics in Chemical Neuroscience: Ibogaine. ACS chemical neuroscience, 9(10), 2475-2483., 10.1021/acschemneuro.8b00294
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Neuroscience: Modeling the Brain on Acid.

/ LSD, Neuroscience, Papers, Psychology, Publications / / ,

Abstract

A receptor map of serotonin distribution is integrated into a model of the dynamic activity of the brain under the effects of LSD. The approach opens new avenues to understand experimental manipulations of healthy brain activity and offers a novel drug-discovery platform.
van der Meer, J., & Breakspear, M. (2018). Neuroscience: Modeling the Brain on Acid. Current Biology, 28(19), R1157-R1160. doi: 10.1016/j.cub.2018.08.008, https://doi.org/10.1016/j.cub.2018.08.008
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Increased use of illicit drugs in a Dutch cluster headache population

/ Headache Pain and Neurological Disorders, LSD, Mushrooms / Psilocybin, Neuroscience, Papers, Psychology, Publications / / , , , , ,

Abstract

Introduction

Many patients with cluster headache report use of illicit drugs. We systematically assessed the use of illicit drugs and their effects in a well-defined Dutch cluster headache population.

Methods

In this cross-sectional explorative study, 756 people with cluster headache received a questionnaire on lifetime use and perceived effects of illicit drugs. Results were compared with age and sex-matched official data from the Dutch general population.

Results

Compared to the data from the general population, there were more illicit drug users in the cluster headache group (31.7% vs. 23.8%; p < 0.01). Reduction in attack frequency was reported by 56% (n = 22) of psilocybin mushroom, 60% (n = 3) of lysergic acid diethylamide and 50% (n = 2) of heroin users, and a decreased attack duration was reported by 46% (n = 18) of PSI, 50% (n = 2) of heroin and 36% (n = 8) of amphetamine users.

Conclusion

In the Netherlands, people with cluster headache use illicit drugs more often than the general population. The question remains whether this is due to an actual alleviatory effect, placebo response, conviction, or common pathophysiological background between cluster headache and addictive behaviours such as drug use.

de Coo, I. F., Naber, W. C., Wilbrink, L. A., Haan, J., Ferrari, M. D., & Fronczek, R. (2018). Increased use of illicit drugs in a Dutch cluster headache population. Cephalalgia., 10.1177/0333102418804160
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The neuropharmacology of sleep paralysis hallucinations: serotonin 2A activation and a novel therapeutic drug

/ LSD, Mushrooms / Psilocybin, Neuroscience, Papers, Psychotic Disorders, Publications / /

Abstract

Sleep paralysis is a state of involuntary immobility occurring at sleep onset or offset, often accompanied by uncanny “ghost-like” hallucinations and extreme fear reactions. I provide here a neuropharmacological account for these hallucinatory experiences by evoking the role of the serotonin 2A receptor (5-HT2AR). Research has shown that 5-HT2AR activation can induce visual hallucinations, “mystical” subjective states, and out-of-body experiences (OBEs), and modulate fear circuits. Hallucinatory experiences triggered by serotonin-serotonergic (“pseudo”) hallucinations, induced by hallucinogenic drugs-tend to be “dream-like” with the experiencer having insight (“meta-awareness”) that he is hallucinating, unlike dopaminergic (“psychotic” and “life-like”) hallucinations where such insight is lost. Indeed, hallucinatory experiences during sleep paralysis have the classic features of serotonergic hallucinations, and are strikingly similar to perceptual and subjective states induced by hallucinogenic drugs (e.g., lysergic acid diethylamide [LSD] and psilocybin), i.e., they entail visual hallucinations, mystical experiences, OBEs, and extreme fear reactions. I propose a possible mechanism whereby serotonin could be functionally implicated in generating sleep paralysis hallucinations and fear reactions through 5-HT2AR activity. Moreover, I speculate on the role of 5-HT2C receptors vis-à-vis anxiety and panic during sleep paralysis, and the orbitofrontal cortex-rich with 5-HT2A receptors-in influencing visual pathways during sleep paralysis, and, in effect, hallucinations. Finally, I propose, for the first time, a drug to target sleep paralysis hallucinations and fear reactions, namely the selective 5-HT2AR inverse agonist, pimavanserin. This account implicates gene HTR2A on chromosome 13q as the underlying cause of sleep paralysis hallucinations and could be explored using positron emission tomography.

Jalal, B. (2018). The neuropharmacology of sleep paralysis hallucinations: serotonin 2A activation and a novel therapeutic drug. Psychopharmacology, 235(11), 3083-3091.,  10.1007/s00213-018-5042-1

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Advances and challenges in neuroimaging studies on the effects of serotonergic hallucinogens: Contributions of the resting brain.

/ Ayahuasca, LSD, Mushrooms / Psilocybin, Neuroscience, Papers, Psychology, Publications / / , , , , , ,

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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Whole-Brain Multimodal Neuroimaging Model Using Serotonin Receptor Maps Explains Non-linear Functional Effects of LSD

/ Neuroscience, Papers, Publications / / , , , , , ,

Abstract

Understanding the underlying mechanisms of the human brain in health and disease will require models with necessary and sufficient details to explain how function emerges from the underlying anatomy and is shaped by neuromodulation. Here, we provide such a detailed causal explanation using a whole-brain model integrating multimodal imaging in healthy human participants undergoing manipulation of the serotonin system. Specifically, we combined anatomical data from diffusion magnetic resonance imaging (dMRI) and functional magnetic resonance imaging (fMRI) with neurotransmitter data obtained with positron emission tomography (PET) of the detailed serotonin 2A receptor (5-HT2AR) density map. This allowed us to model the resting state (with and without concurrent music listening) and mechanistically explain the functional effects of 5-HT2AR stimulation with lysergic acid diethylamide (LSD) on healthy participants. The whole-brain model used a dynamical mean-field quantitative description of populations of excitatory and inhibitory neurons as well as the associated synaptic dynamics, where the neuronal gain function of the model is modulated by the 5-HT2AR density. The model identified the causative mechanisms for the non-linear interactions between the neuronal and neurotransmitter system, which are uniquely linked to (1) the underlying anatomical connectivity, (2) the modulation by the specific brainwide distribution of neurotransmitter receptor density, and (3) the non-linear interactions between the two. Taking neuromodulatory activity into account when modeling global brain dynamics will lead to novel insights into human brain function in health and disease and opens exciting possibilities for drug discovery and design in neuropsychiatric disorders.

Deco, G., Cruzat, J., Cabral, J., Knudsen, G. M., Carhart-Harris, R. L., Whybrow, P. C., … & Kringelbach, M. L. (2018). Whole-brain multimodal neuroimaging model using serotonin receptor maps explains non-linear functional effects of LSD. Current biology, 28(19), 3065-3074., 10.1016/j.cub.2018.07.083

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Neurocognitive effects of six ketamine infusions and the association with antidepressant response in patients with unipolar and bipolar depression

/ Ketamine, Neuroscience, Papers, Psychiatry & Medicine, Psychology, Publications / / , , , , , ,

Abstract

BACKGROUND:

Ketamine has proven to have rapid, robust antidepressant effects on treatment-resistant depression. However, whether repeated ketamine infusions would cause short-and long-term neurocognitive impairments was not clear. Our aims were to investigate the neurocognitive effects of six ketamine infusions and to examine the association between these infusions and the antidepressant response in patients with unipolar and bipolar depression.

METHODS:

Six intravenous infusions of ketamine (0.5 mg/kg) over a 12-day period were administered to 84 patients with unipolar and bipolar depression. Severity of depressive symptoms and four domains of neurocognition, including speed of processing, working memory, visual learning and verbal learning, were assessed at baseline, one day following the last infusion and again two weeks post-infusion.

RESULTS:

Significant improvements were found on speed of processing ( F=9.344, p<0.001) and verbal learning ( F=5.647, p=0.004) in a linear mixed model. The Sobel test showed significant indirect effects between time and improvement in speed of processing (Sobel test=3.573, p<0.001) as well as improvement in verbal learning (Sobel test=6.649, p<0.001), which were both significantly mediated by change in depressive symptoms. Logistic regression analysis showed ketamine responders had better visual learning at baseline than non-responders (B=0.118, p<0.001).

CONCLUSIONS:

Our findings suggest that neurocognitive function would not deteriorate after six ketamine infusions, while verbal learning and speed of processing improved over 13 days and 26 days of observation, respectively. However, this change was mainly accounted for by improvements in severity of depressive symptoms over time. Greater baseline visual learning predicted an antidepressant response over six ketamine infusions.

Zhou, Y., Zheng, W., Liu, W., Wang, C., Zhan, Y., Li, H., … & Ning, Y. (2018). Neurocognitive effects of six ketamine infusions and the association with antidepressant response in patients with unipolar and bipolar depression. Journal of Psychopharmacology, 32(10), 1118-1126, 10.1177/0269881118798614
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Awe: a putative mechanism underlying the effects of classic psychedelic-assisted psychotherapy

/ Papers, Psychology, Publications / /

Abstract

A psychological model of classic psychedelic-assisted psychotherapy informed by contemporary scientific data is presented in this paper. It is suggested that classic psychedelic-occasioned mystical experience is characterized by profound awe, a discrete emotion experienced in the presence of a vast stimulus requiring accommodation of mental structures. Awe, in turn, promotes the small self, a construct that, in the extreme, is analogous to those of unitive experience and ego dissolution. The small self is conceptualized as key to understanding the downstream effects of mystical experience occasioned in the context of classic psychedelic-assisted psychotherapy. With this novel theoretical framework in mind, a number of clinical implications and recommendations are provided so as to advance this incipient field of study.
Hendricks, P. S. (2018). Awe: a putative mechanism underlying the effects of classic psychedelic-assisted psychotherapy. International Review of Psychiatry, 30(4), 331-342., 10.1080/09540261.2018.1474185
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Understanding Central Nervous System Effects of Deliriant Hallucinogenic Drugs through Experimental Animal Models

/ Neuroscience, Papers, Psychiatry & Medicine, Publications / / , , , , , ,

Abstract

Hallucinogenic drugs potently alter human behavior and have a millennia-long history of use for medicinal and religious purposes. Interest is rapidly growing in their potential as CNS modulators and therapeutic agents for brain conditions. Antimuscarinic cholinergic drugs, such as atropine and scopolamine, induce characteristic hyperactivity and dream-like hallucinations and form a separate group of hallucinogens known as “deliriants”. Although atropine and scopolamine are relatively well-studied drugs in cholinergic physiology, deliriants represent the least-studied class of hallucinogens in terms of their behavioral and neurological phenotypes. As such, novel approaches and new model organisms are needed to investigate the CNS effects of these compounds. Here, we comprehensively evaluate the preclinical effects of deliriant hallucinogens in various animal models, their mechanisms of action, and potential interplay with other signaling pathways. We also parallel experimental and clinical findings on deliriant agents and outline future directions of translational research in this field.

Volgin, A. D., Yakovlev, O. A., Demin, K. A., Alekseeva, P. A., Kyzar, E. J., Collins, C., … & Kalueff, A. V. (2018). Understanding Central Nervous System Effects of Deliriant Hallucinogenic Drugs through Experimental Animal Models. ACS chemical neuroscience., 10.1021/acschemneuro.8b00433

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Psychedelics and the new behaviourism: considering the integration of third-wave behaviour therapies with psychedelic-assisted therapy

/ Neuroscience, Papers, Psychology, Publications / / ,

Abstract

This narrative review examines evidence related to the potential for third wave behaviour therapies to serve as adjuncts to psychedelic-assisted therapy. It identifies shared theoretical foundations for both approaches, and notes enhanced mindfulness, decentering, emotion regulation, and distress tolerance as common mechanisms of action. It also identifies potential targets for which both approaches have demonstrated therapeutic potential, including problematic substance use, self-directed and other-directed violence, and mood disorders. Based on these commonalities, there is a call for research on the potential integration of psychedelic-assisted therapy and third wave behaviour therapies including Dialectical Behaviour Therapy, Acceptance and Commitment Therapy, and Mindfulness Based Cognitive Therapy.

Walsh, Z., & Thiessen, M. S. (2018). Psychedelics and the new behaviourism: considering the integration of third-wave behaviour therapies with psychedelic-assisted therapy. International Review of Psychiatry, 30(4), 343-349., 10.1080/09540261.2018.1474088
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Psychedelics in Palliative Care: Clinical and Ethical Considerations - October 27th

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