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Total Recall: Lateral Habenula and Psychedelics in the Study of Depression and Comorbid Brain Disorders

Abstract

Depression impacts the lives and daily activities of millions globally. Research into the neurobiology of lateral habenula circuitry and the use of psychedelics for treating depressive states has emerged in the last decade as new directions to devise interventional strategies and therapies. Several clinical trials using deep brain stimulation of the habenula, or using ketamine, and psychedelics that target the serotonergic system such as psilocybin are also underway. The promising early results in these fields require cautious optimism as further evidence from experiments conducted in animal systems in ecologically relevant settings, and a larger number of human studies with improved spatiotemporal neuroimaging, accumulates. Designing optimal methods of intervention will also be aided by an improvement in our understanding of the common genetic and molecular factors underlying disorders comorbid with depression, as well as the characterization of psychedelic-induced changes at a molecular level. Advances in the use of cerebral organoids offers a new approach for rapid progress towards these goals. Here, we review developments in these fast-moving areas of research and discuss potential future directions.

Vitkauskas, M., & Mathuru, A. S. (2020). Total Recall: Lateral Habenula and Psychedelics in the Study of Depression and Comorbid Brain Disorders. International journal of molecular sciences, 21(18), 6525. https://doi.org/10.3390/ijms21186525

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Psilocybin as a New Approach to Treat Depression and Anxiety in the Context of Life-Threatening Diseases-A Systematic Review and Meta-Analysis of Clinical Trials

Abstract

Psilocybin is a naturally occurring tryptamine known for its psychedelic properties. Recent research indicates that psilocybin may constitute a valid approach to treat depression and anxiety associated to life-threatening diseases. The aim of this work was to perform a systematic review with meta-analysis of clinical trials to assess the therapeutic effects and safety of psilocybin on those medical conditions. The Beck Depression Inventory (BDI) was used to measure the effects in depression and the State-Trait Anxiety Inventory (STAI) was used to measure the effects in anxiety. For BDI, 11 effect sizes were considered (92 patients) and the intervention group was significantly favored (WMD = -4.589; 95% CI = -4.207 to -0.971; p-value = 0.002). For STAI-Trait, 11 effect sizes were considered (92 patients), being the intervention group significantly favored when compared to the control group (WMD = -5.906; 95% CI = -7.852 to -3.960; p-value ˂ 0.001). For STAI-State, 9 effect sizes were considered (41 patients) and the intervention group was significantly favored (WMD = -6.032; 95% CI = -8.900 to -3.164; p-value ˂ 0.001). The obtained results are promising and emphasize the importance of psilocybin translational research in the management of symptoms of depression and anxiety, since the compound may be effective in reducing symptoms of depression and anxiety in conditions that are either resistant to conventional pharmacotherapy or for which pharmacologic treatment is not yet approved. Moreover, it may be also relevant for first-line treatment, given its safety.

Vargas, A. S., Luís, Â., Barroso, M., Gallardo, E., & Pereira, L. (2020). Psilocybin as a New Approach to Treat Depression and Anxiety in the Context of Life-Threatening Diseases-A Systematic Review and Meta-Analysis of Clinical Trials. Biomedicines, 8(9), 331. https://doi.org/10.3390/biomedicines8090331

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The psychoactive aminoalkylbenzofuran derivatives, 5-APB and 6-APB, mimic the effects of 3,4-methylenedioxyamphetamine (MDA) on monoamine transmission in male rats

Abstract

Rationale: The nonmedical use of new psychoactive substances (NPS) is a worldwide public health concern. The so-called “benzofury” compounds, 5-(2-aminopropyl)benzofuran (5-APB) and 6-(2-aminopropyl)benzofuran (6-APB), are NPS with stimulant-like properties in human users. These substances are known to interact with monoamine transporters and 5-HT receptors in transfected cells, but less is known about their effects in animal models.

Methods: Here, we used in vitro monoamine transporter assays in rat brain synaptosomes to characterize the effects of 5-APB and 6-APB, together with their N-methyl derivatives 5-MAPB and 6-MAPB, in comparison with 3,4-methylenedioxyamphetamine (MDA) and 3,4-methylenedioxymethamphetamine (MDMA). In vivo neurochemical and behavioral effects of 5-APB (0.3 and 1.0 mg/kg, i.v.) and 6-APB (0.3 and 1.0 mg/kg, i.v.) were assessed in comparison with MDA (1.0 and 3.0 mg/kg, i.v.) using microdialysis sampling in the nucleus accumbens of conscious male rats.

Results: All four benzofuran derivatives were substrate-type releasers at dopamine transporters (DAT), norepinephrine transporters (NET), and serotonin transporters (SERT) with nanomolar potencies, similar to the profile of effects produced by MDA and MDMA. However, the benzofurans were at least threefold more potent than MDA and MDMA at evoking transporter-mediated release. Like MDA, both benzofurans induced dose-related elevations in extracellular dopamine and serotonin in the brain, but benzofurans were more potent than MDA. The benzofuran derivatives also induced profound behavioral activation characterized by forward locomotion which lasted for at least 2 h post-injection.

Conclusions: Overall, benzofurans are more potent than MDA in vitro and in vivo, producing sustained stimulant-like effects in rats. These data suggest that benzofuran-type compounds may have abuse liability and could pose risks for adverse effects, especially if used in conjunction with abused drugs or medications which enhance monoamine transmission in the brain.

Brandt, S. D., Walters, H. M., Partilla, J. S., Blough, B. E., Kavanagh, P. V., & Baumann, M. H. (2020). The psychoactive aminoalkylbenzofuran derivatives, 5-APB and 6-APB, mimic the effects of 3, 4-methylenedioxyamphetamine (MDA) on monoamine transmission in male rats. Psychopharmacology237(12), 3703-3714; 10.1007/s00213-020-05648-z

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Low Doses of LSD Acutely Increase BDNF Blood Plasma Levels in Healthy Volunteers

Abstract

Despite preclinical evidence for psychedelic-induced neuroplasticity, confirmation in humans is grossly lacking. Given the increased interest in using low doses of psychedelics for psychiatric indications and the importance of neuroplasticity in the therapeutic response, this placebo-controlled within-subject study investigated the effect of single low doses of LSD (5, 10, and 20 μg) on circulating BDNF levels in healthy volunteers. Blood samples were collected every 2 h over 6 h, and BDNF levels were determined afterward in blood plasma using ELISA. The findings demonstrated an increase in BDNF blood plasma levels at 4 h (5 μg) and 6 h (5 and 20 μg) compared to that for the placebo. The finding that LSD acutely increases BDNF levels warrants studies in patient populations.

Hutten, N., Mason, N. L., Dolder, P. C., Theunissen, E. L., Holze, F., Liechti, M. E., Varghese, N., Eckert, A., Feilding, A., Ramaekers, J. G., & Kuypers, K. (2020). Low Doses of LSD Acutely Increase BDNF Blood Plasma Levels in Healthy Volunteers. ACS pharmacology & translational science, 4(2), 461–466. https://doi.org/10.1021/acsptsci.0c00099

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Phytochemical, Cytotoxicity, Antioxidant and Anti-Inflammatory Effects of Psilocybe Natalensis Magic Mushroom

Abstract

Psilocybin-containing mushrooms, commonly known as magic mushrooms, have been used since ancient and recent times for depression and to improve quality of life. However, their anti-inflammatory properties are not known. The study aims at investing cytotoxicity; antioxidant; and, for the first time, anti-inflammatory effects of Psilocybe natalensis, a psilocybin-containing mushroom that grows in South Africa, on lipopolysaccharide-induced RAW 264.7 macrophages. Macrophage cells were stimulated with lipopolysaccharide and treated with different concentrations of Psilocybe natalensis mushroom extracted with boiling hot water, cold water and ethanol over 24 h. Quercetin and N-nitro-L-arginine methyl ester were used as positive controls. Effects of extracts on the lipopolysaccharide-induced nitric oxide, prostaglandin E2, and cytokine activities were investigated. Phytochemical analysis, and the antioxidant and cytotoxicity of extracts, were determined. Results showed that the three extracts inhibited the lipopolysaccharide-induced nitric oxide, prostaglandin E2, and interleukin 1β cytokine production significantly in a dose-dependent manner close to that of the positive controls. A study proposed that ethanol and water extracts of Psilocybe natalensis mushroom were safe at concentrations used, and have antioxidant and anti-inflammatory effects. Phytochemical analysis confirmed the presence of natural antioxidant and anti-inflammatory compounds in the mushroom extracts.

Nkadimeng, S. M., Nabatanzi, A., Steinmann, C. M., & Eloff, J. N. (2020). Phytochemical, Cytotoxicity, Antioxidant and Anti-Inflammatory Effects of Psilocybe Natalensis Magic Mushroom. Plants9(9), 1127; https://doi.org/10.3390/plants9091127

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Who takes the trip? Personality and hallucinogen use among college students and adolescents

Abstract

Research examining hallucinogen use has identified potential benefits, as well as potential harms, associated with use. The acute effects of hallucinogen use can be intense, disorienting, cognitively impairing, and may result in perceptual changes mimicking aspects of temporary psychosis. Hallucinogen use may also lead to the onset of more chronic issues, such as Hallucinogen Persisting Perception Disorder, which impairs daily functioning even when sober. However, research on factors that predict who will misuse hallucinogens is an understudied area. In particular, while sensation seeking, impulsivity, and emotion dysregulation have all been shown to be predictive of problematic substance misuse, there is almost no research on how these personality variables predict hallucinogen use. The present study assessed how these personality traits predicted hallucinogen use in a sample of college undergraduates (N = 10,251) and a sample of adolescents in an inpatient residential psychiatric hospital (N = 200). Results indicated that facets of sensation seeking, impulsivity, and emotion dysregulation positively predicted ever having used hallucinogens, earlier initiation of use, and lifetime use among college students. Findings also indicated that facets of sensation seeking, impulsivity, and emotion dysregulation positively predicted having ever used hallucinogens in the adolescent inpatient sample. Results highlight the need for more research on who is likely to misuse hallucinogens. If confirmed in future research, the findings presented herein indicate viable personality variables as predictors. This is especially important as there has been a recent explosion of research on the positive benefits of therapeutic hallucinogen use.

Parnes, J. E., Kentopp, S. D., Conner, B. T., & Rebecca, R. A. (2020). Who takes the trip? Personality and hallucinogen use among college students and adolescents. Drug and alcohol dependence, 217, 108263. https://doi.org/10.1016/j.drugalcdep.2020.108263

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The Antidepressant Effect of Ketamine Is Dampened by Concomitant Benzodiazepine Medication

Abstract

The rapid antidepressant effect of ketamine has become a breakthrough in the research and treatment of depression. Although predictive and modulating factors of the response to ketamine are broadly studied, little is known about optimal concurrent medication protocols. Concerning gamma-aminobutyric acid neurotransmission being a shared target for both ketamine and benzodiazepines (BZD), we evaluated the influence of BZD on the antidepressant effect of a single ketamine infusion in depressed patients. Data from 47 patients (27 females) with major depression (MADRS ≥ 20, ≥ 1 prior nonresponse to antidepressant treatment in current episode) who participated in two previous studies (EudraCT Number: 2009-010625-39 and 2013-000952-17) entered the analysis. All of the subjects were given an infusion of a subanesthetic dose of racemic ketamine (0.54 mg per kg) as an add-on medication to ongoing antidepressant treatment. Thirteen patients (28%) reached ≥ 50% reduction in MADRS within one week after ketamine administration. Nineteen (40%) patients took concomitant benzodiazepines on a daily basis. The doses of BZDs were significantly higher in nonresponders (p=0.007). ROC analysis distinguished responders from nonresponders by a criterion of >8mg of diazepam equivalent dose (DZ equivalent) with a sensitivity of 80% and a specificity of 85% (p<0.001). RM-ANOVA revealed a different time pattern of response to ketamine between the BZD+ (>8mg of DZ equivalent) and BZD- (≤8mg of DZ equivalent) groups, with a significantly worse outcome in BZD+ on day 3 (p=0.04) and day 7 (p=0.02). The results of the study indicate that concomitant benzodiazepine treatment in higher doses may attenuate ketamine’s antidepressant effect. The pathophysiological, clinical and methodological implications of this finding should be considered in future research and ketamine treatment.

Andrashko, V., Novak, T., Brunovsky, M., Klirova, M., Sos, P., & Horacek, J. (2020). The Antidepressant Effect of Ketamine Is Dampened by Concomitant Benzodiazepine Medication. Frontiers in psychiatry, 11, 844. https://doi.org/10.3389/fpsyt.2020.00844

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The therapeutic potential of microdosing psychedelics in depression

Abstract

Microdosing psychedelics is the repeated use of small doses of, for example, lysergic acid diethylamide (LSD) and psilocybin, typically for a few weeks. Despite the popular and scientific attention in recent years, and claims by users that it has therapeutic value in affective disorders like depression, little scientific knowledge is available to back this. The purpose of this review was to investigate whether there are scientific grounds to state that this practice could be helpful in the treatment of affective disorders, and safe to use repeatedly. To that end, the literature (PubMed, MedLine) was searched, looking for (controlled) experimental studies with low doses of LSD and/or psilocybin, in healthy volunteers and patient samples. After a selection process and the addition of relevant articles, 14 experimental studies entered this review. Findings show that both LSD (10-20 mcg) and psilocybin (<1-3 mg) have subtle (positive) effects on cognitive processes (time perception, convergent and divergent thinking) and brain regions involved in affective processes. Besides the pleasant experience, increased anxiety and a cycling pattern of depressive and euphoric mood were also found. With regard to safety, it was demonstrated that low doses are well tolerated (in healthy volunteers) and have no-to-minimal effects on physiological measures. While it is yet unclear whether psychedelic microdosing is of therapeutic value for depression, the aforementioned effects on selective processes suggest that low doses of psychedelics could play a role in depression by inducing some kind of cognitive flexibility, which might lead to decreased rumination. While previous studies were conducted mostly in small samples of healthy volunteers, future placebo-controlled clinical trials in depressed patients are required to understand the therapeutic value of microdosing psychedelics, how this differs from therapy using full psychedelic doses, and whether different psychedelics have different effect patterns. The proposed research will give new insights into the potential of future alternative psychiatric treatment forms that are fiercely needed.

Kuypers K. (2020). The therapeutic potential of microdosing psychedelics in depression. Therapeutic advances in psychopharmacology, 10, 2045125320950567. https://doi.org/10.1177/2045125320950567

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Plasma psilocin critically determines behavioral and neurobiological effects of psilocybin

Madsen, M. K., & Knudsen, G. M. (2021). Plasma psilocin critically determines behavioral and neurobiological effects of psilocybin. Neuropsychopharmacology: official publication of the American College of Neuropsychopharmacology46(1), 257-258; 10.1038/s41386-020-00823-4
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