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Other substances

The Use of Classic Hallucinogens/Psychedelics in a Therapeutic Context: Healthcare Policy Opportunities and Challenges


Psychedelics or serotonergic hallucinogens are a group of substances that share the agonism of serotonergic 5-HT2A receptors as their main mechanism of action. Its main effects include changes in perception, cognitive process, and mood. Despite being used for centuries by different cultures in ritual contexts, these substances have currently aroused the interest of science and industry for their promising antidepressant, anxiolytic, and anti-addictive effects. Considering this evidence, this article aims to explore some of the possible health policy challenges to integrate these therapeutic tools into broad and heterogeneous health systems. As a main benefit, these substances produce rapid and enduring effects with the administration of single or few doses, which could lead to new treatment possibilities for patients with severe mental disorders resistant to the usual medications. The main challenge is associated with the fact that these substances remain scheduled in most countries and are associated with social stigma related to their recreational use (especially LSD and psilocybin). This situation makes it exceedingly difficult to conduct clinical trials, although international conventions allow such research. Ethically, this could be interpreted as a violation of human rights since thousands of people are prevented from having access to possible benefits. Interestingly, ritual ayahuasca use is more acceptable to the public than the use of psilocybin-containing mushrooms or LSD. The controlled, clinical use of LSD and psilocybin seems to be less criticized and is being explored by the industry. Rigorous scientific evidence coupled with industrial interests (LSD and psilocybin), together with respect for traditional uses (ayahuasca) and international conventions, seems to be the best way for these drugs to be integrated into health systems in the next years. Which highlights the need for an urgent dialogue between science, health system, society, and politics.

Dos Santos, R. G., Bouso, J. C., Rocha, J. M., Rossi, G. N., & Hallak, J. E. (2021). The Use of Classic Hallucinogens/Psychedelics in a Therapeutic Context: Healthcare Policy Opportunities and Challenges. Risk management and healthcare policy, 14, 901–910.

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Trends in the Top-Cited Articles on Classic Psychedelics


This study was designed to identify trends in the top-cited classic psychedelic publications. The top 50 publications on classic psychedelics with the greatest total of number of citations and annual citation rate were identified and pooled. Unique articles (n = 76) were dichotomized by median year of publication (2010.5); the differential distribution of study characteristics between the “Recent Cohort” (n = 38) and “Older Cohort” (n = 38) were documented. The Recent Cohort had a greater annual citation rate (median 76.0, IQR 38.5 to 101.5) compared to the Older Cohort (median10.0, IQR 5.2 to 19.3, p < .001). The Recent Cohort included a greater number of clinical studies (n = 26 [68.4%] vs. n = 9 [23.7%]) while the Older Cohort included more basic science and preclinical studies (n = 21 [55.3%] vs. n = 2 [5.3%], p < .001). Psilocybin was the predominant psychedelic studied in the Recent Cohort (n = 25 [65.8%] vs. n = 9 [23.7%]) while lysergic acid diethylamide (LSD) was predominantly studied in the Older Cohort (n = 25 [65.8%] vs. n = 18 [47.4%], p = .013). The Recent Cohort included more studies examining affective disorders (n = 15 [39.5%] vs. n = 3 [7.9%]) and substance use disorders (n = 6 [15.8%] vs. n = 0 [0.0%]), while the Older Cohort included a greater number of pharmacological outcomes (n = 29 [76.3%] vs. n = 6 [15.8%], p < .001). This study identified and documented trends in the top-cited classic psychedelic publications. The field is continuing to form a foundational understanding of the pharmacological effects of psychedelics and is now advancing with the identification of therapeutic uses within clinical populations.

Lawrence, D. W., Sharma, B., Griffiths, R. R., & Carhart-Harris, R. (2021). Trends in the Top-Cited Articles on Classic Psychedelics. Journal of psychoactive drugs, 53(4), 283–298.

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Psychedelics, placebo effects, and set and setting: Insights from common factors theory of psychotherapy


Psychedelic-assisted treatment is at first glance markedly different in structure and approach from mainstream forms of psychotherapy in the West. A major criticism of clinical psychedelic research rests on the difficulty of executing placebo-controlled studies and distinguishing drug effects from those of the psychotherapeutic container in which psychedelics are typically presented. Detractors also tend to find fault in spiritual or mystical themes that often arise in the context of psychedelic use. Common factors theory of psychotherapy is a useful and extensively studied framework that can help make sense of these issues, and has much to contribute to our understanding of contextual effects that are often discussed in psychedelic literature as “set and setting.” In this article, we examine four major contextual “common factors” shared by various healing traditions: 1) the therapeutic relationship; 2) the healing setting; 3) the rationale, conceptual scheme, or myth; and 4) the ritual. We explain how these factors show up in psychedelic-assisted treatment and how they may contribute to therapeutic effects. Lastly, we discuss the implications of these factors for the concept of placebo, and for future research.

Gukasyan, N., & Nayak, S. M. (2021). Psychedelics, placebo effects, and set and setting: Insights from common factors theory of psychotherapy. Transcultural psychiatry, 1363461520983684. Advance online publication.

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Harmine inhibits the proliferation and migration of glioblastoma cells via the FAK/AKT pathway


Aims: Glioblastoma is one of the most invasive tumors of the central nervous system, and has a high degree of malignancy and poor prognosis. Harmine, an active ingredient extracted from perennial herbs, has been reported to have obvious antitumor effects on various tumors. However, the effects of harmine on glioblastoma growth remain unknown. We here explored the effects of harmine on glioblastoma and its underlying molecular mechanisms related to tumorigenesis.

Materials and methods: CCK-8 and immunofluorescent assay were performed to measure anti-proliferative effect of harmine on U251-MG and U373-MG cells. Wound healing assay was performed to measure the effects of harmine on cell migration. qRT-PCR and western blot were performed to detect the protein/gene expression. BALB/c nude mice bearing U251-MG xenografts was used to measure the effects of harmine on the growth of glioblastoma in vivo.

Key findings: Harmine treatment significantly suppressed the proliferation of U251-MG and U373-MG cells in a dose and time-dependent way. Mechanistically, harmine reduced the basal and EGF-enhanced the phosphorylation level of FAK and AKT. Moreover, harmine inhibited the cell viability of U251-MG and U373-MG cells by downregulating the phosphorylation of the FAK/AKT pathway. Besides, harmine significantly suppressed the migration of U251-MG cells by suppressing the expression of MMP2, MMP9 and VEGF. Subsequently, orthotopic xenograft models revealed that harmine treatment dramatically inhibited the growth of glioblastoma in vivo.

Significance: In conclusion, these results suggest that harmine suppresses the proliferation and migration of U251-MG and U373-MG cells by inhibiting the FAK/AKT signaling pathway. Our findings elucidate harmine could be a promising drug for glioblastoma therapy.

Zhu, Y. G., Lv, Y. X., Guo, C. Y., Xiao, Z. M., Jiang, Q. G., Kuang, H., Zhang, W. H., & Hu, P. (2021). Harmine inhibits the proliferation and migration of glioblastoma cells via the FAK/AKT pathway. Life sciences, 270, 119112.

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Ketamine and Serotonergic Psychedelics: Common Mechanisms Underlying the Effects of Rapid-Acting Antidepressants


Background: The glutamatergic modulator ketamine has created a blueprint for studying novel pharmaceuticals in the field. Recent studies suggest that “classic” serotonergic psychedelics (SPs) may also have antidepressant efficacy. Both ketamine and SPs appear to produce rapid, sustained antidepressant effects after a transient psychoactive period.

Methods: This review summarizes areas of overlap between SP and ketamine research and considers the possibility of a common, downstream mechanism of action. The therapeutic relevance of the psychoactive state, overlapping cellular and molecular effects, and overlapping electrophysiological and neuroimaging observations are all reviewed.

Results: Taken together, the evidence suggests a potentially shared mechanism wherein both ketamine and SPs may engender rapid neuroplastic effects in a glutamatergic activity-dependent manner. It is postulated that, though distinct, both ketamine and SPs appear to produce acute alterations in cortical network activity that may initially produce psychoactive effects and later produce milder, sustained changes in network efficiency associated with therapeutic response. However, despite some commonalities between the psychoactive component of these pharmacologically distinct therapies-such as engagement of the downstream glutamatergic pathway-the connection between psychoactive impact and antidepressant efficacy remains unclear and requires more rigorous research.

Conclusions: Rapid-acting antidepressants currently under investigation may share some downstream pharmacological effects, suggesting that their antidepressant effects may come about via related mechanisms. Given the prototypic nature of ketamine research and recent progress in this area, this platform could be used to investigate entirely new classes of antidepressants with rapid and robust actions.

Kadriu, B., Greenwald, M., Henter, I. D., Gilbert, J. R., Kraus, C., Park, L. T., & Zarate, C. A. (2021). Ketamine and Serotonergic Psychedelics: Common Mechanisms Underlying the Effects of Rapid-Acting Antidepressants. The international journal of neuropsychopharmacology, 24(1), 8–21.

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Classical Psychedelics as Therapeutics in Psychiatry – Current Clinical Evidence and Potential Therapeutic Mechanisms in Substance Use and Mood Disorders


Classical psychedelics, primarily psilocybin and lysergic acid diethylamide (LSD), have been used and extensively studied in Western medicine as part of substance-assisted psychotherapy in the 1950s and 1960s. Modern clinical research is currently gaining momentum and provides new evidence for the safety and efficacy of classical psychedelics (primarily psilocybin, but also LSD and ayahuasca) in the treatment of different psychiatric conditions, including substance use and mood disorders.In this review article, we outline common pathological mechanisms of substance use disorders (SUD) and unipolar depression. Next, the current literature on the effects of psychedelics is summarized in order to generate hypotheses regarding their potential therapeutic mechanisms of action in treating these psychiatric conditions. Finally, we review and discuss clinical trials published since 2011 investigating the effects of psychedelics in SUD and depression.While results from those modern clinical trials are promising, most of them do not meet the methodological requirements to allow firm conclusions on the clinical efficacy of psychedelics. Larger, blinded, randomized controlled trials (RCT) with clearly defined patient groups and well-defined primary endpoints are needed. Additionally, the therapeutic mechanisms of classical psychedelics are currently unknown. This review presents hypotheses derived from preclinical and human studies that need to be tested in future trials to better understand the clinical potential of psychedelic substances in modern psychiatry.

Mertens, L. J., & Preller, K. H. (2021). Classical Psychedelics as Therapeutics in Psychiatry – Current Clinical Evidence and Potential Therapeutic Mechanisms in Substance Use and Mood Disorders. Pharmacopsychiatry, 54(4), 176–190.

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Classic serotonergic psychedelics for mood and depressive symptoms: a meta-analysis of mood disorder patients and healthy participants


Rationale: Major depressive disorder is one of the leading global causes of disability, for which the classic serotonergic psychedelics have recently reemerged as a potential therapeutic treatment option.

Objective: We present the first meta-analytic review evaluating the clinical effects of classic serotonergic psychedelics vs placebo for mood state and symptoms of depression in both healthy and clinical populations (separately).

Results: Our search revealed 12 eligible studies (n = 257; 124 healthy participants, and 133 patients with mood disorders), with data from randomized controlled trials involving psilocybin (n = 8), lysergic acid diethylamide ([LSD]; n = 3), and ayahuasca (n = 1). The meta-analyses of acute mood outcomes (3 h to 1 day after treatment) for healthy volunteers and patients revealed improvements with moderate significant effect sizes in favor of psychedelics, as well as for the longer-term (16 to 60 days after treatments) mood state of patients. For patients with mood disorder, significant effect sizes were detected on the acute, medium (2-7 days after treatment), and longer-term outcomes favoring psychedelics on the reduction of depressive symptoms.

Conclusion: Despite the concerns over unblinding and expectancy, the strength of the effect sizes, fast onset, and enduring therapeutic effects of these psychotherapeutic agents encourage further double-blind, placebo-controlled clinical trials assessing them for management of negative mood and depressive symptoms.

Galvão-Coelho, N. L., Marx, W., Gonzalez, M., Sinclair, J., de Manincor, M., Perkins, D., & Sarris, J. (2021). Classic serotonergic psychedelics for mood and depressive symptoms: a meta-analysis of mood disorder patients and healthy participants. Psychopharmacology, 238(2), 341–354.

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The acute effects of classic psychedelics on memory in humans


Rationale: Memory plays a central role in the psychedelic experience. The spontaneous recall and immersive reliving of autobiographical memories has frequently been noted by researchers and clinicians as a salient phenomenon in the profile of subjective effects of classic psychedelic drugs such as psilocybin, LSD, and ayahuasca. The ability for psychedelics to provoke vivid memories has been considered important to their clinical efficacy.

Objective: This review aims to examine and aggregate the findings from experimental, observational, and qualitative studies on the acute modulation of memory by classic psychedelics in humans.

Method: A literature search was conducted using PubMed and PsycInfo as well as manual review of references from eligible studies. Publications reporting quantitative and/or qualitative findings were included; animal studies and case reports were excluded.

Results: Classic psychedelics produce dose-dependently increasing impairments in memory task performance, such that low doses produce no impairment and higher doses produce increasing levels of impairment. This pattern has been observed in tasks assessing spatial and verbal working memory, semantic memory, and non-autobiographical episodic memory. Such impairments may be less pronounced among experienced psychedelic users. Classic psychedelics also increase the vividness of autobiographical memories and frequently stimulate the recall and/or re-experiencing of autobiographical memories, often memories that are affectively intense (positively or negatively valenced) and that had been avoided and/or forgotten prior to the experience.

Conclusions: Classic psychedelics dose-dependently impair memory task performance but may enhance autobiographical memory. These findings are relevant to the understanding of psychological mechanisms of action of psychedelic-assisted psychotherapy.

Healy C. J. (2021). The acute effects of classic psychedelics on memory in humans. Psychopharmacology, 238(3), 639–653.

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Psychedelics in Psychiatry: Neuroplastic, Immunomodulatory, and Neurotransmitter Mechanisms


Mounting evidence suggests safety and efficacy of psychedelic compounds as potential novel therapeutics in psychiatry. Ketamine has been approved by the Food and Drug Administration in a new class of antidepressants, and 3,4-methylenedioxymethamphetamine (MDMA) is undergoing phase III clinical trials for post-traumatic stress disorder. Psilocybin and lysergic acid diethylamide (LSD) are being investigated in several phase II and phase I clinical trials. Hence, the concept of psychedelics as therapeutics may be incorporated into modern society. Here, we discuss the main known neurobiological therapeutic mechanisms of psychedelics, which are thought to be mediated by the effects of these compounds on the serotonergic (via 5-HT2A and 5-HT1A receptors) and glutamatergic [via N-methyl-d-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors] systems. We focus on 1) neuroplasticity mediated by the modulation of mammalian target of rapamycin-, brain-derived neurotrophic factor-, and early growth response-related pathways; 2) immunomodulation via effects on the hypothalamic-pituitary-adrenal axis, nuclear factor ĸB, and cytokines such as tumor necrosis factor-α and interleukin 1, 6, and 10 production and release; and 3) modulation of serotonergic, dopaminergic, glutamatergic, GABAergic, and norepinephrinergic receptors, transporters, and turnover systems. We discuss arising concerns and ways to assess potential neurobiological changes, dependence, and immunosuppression. Although larger cohorts are required to corroborate preliminary findings, the results obtained so far are promising and represent a critical opportunity for improvement of pharmacotherapies in psychiatry, an area that has seen limited therapeutic advancement in the last 20 years. Studies are underway that are trying to decouple the psychedelic effects from the therapeutic effects of these compounds. SIGNIFICANCE STATEMENT: Psychedelic compounds are emerging as potential novel therapeutics in psychiatry. However, understanding of molecular mechanisms mediating improvement remains limited. This paper reviews the available evidence concerning the effects of psychedelic compounds on pathways that modulate neuroplasticity, immunity, and neurotransmitter systems. This work aims to be a reference for psychiatrists who may soon be faced with the possibility of prescribing psychedelic compounds as medications, helping them assess which compound(s) and regimen could be most useful for decreasing specific psychiatric symptoms.

Inserra, A., De Gregorio, D., & Gobbi, G. (2021). Psychedelics in Psychiatry: Neuroplastic, Immunomodulatory, and Neurotransmitter Mechanisms. Pharmacological reviews, 73(1), 202–277.

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30 April - Q&A with Rick Strassman