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Mushrooms / Psilocybin

Therapeutic Applications of Classic Hallucinogens

Abstract

This chapter reviews what is known about the therapeutic uses of the serotonergic or classic hallucinogens, i.e., psychoactive drugs such as LSD and psilocybin that exert their effects primarily through agonist activity at serotonin 2A (5HT2A) receptors. Following a review of the history of human use and scientific study of these drugs, the data from clinical research are summarized, including extensive work on the use of classic hallucinogens in the treatment of alcoholism and other addictions, studies of the use of LSD and psilocybin to relieve distress concerning death, particularly in patients with advanced or terminal cancer, and more limited data concerning the use of classic hallucinogens to treat mood and anxiety disorders. A survey of possible mechanisms of clinically relevant effects is provided. The well-established safety of classic hallucinogens is reviewed. To provide a clinical perspective, case summaries are provided of two individuals who received treatment in recent controlled trials of psilocybin: one being treated for alcoholism, the other suffering from anxiety and depression related to fear of death due to a cancer diagnosis. Although promising early phase research conducted from the 1950s through the early 1970s was discontinued before firm conclusions could be reached concerning the efficacy of any of the classic hallucinogens for any clinical condition, the research that was conducted in that era strongly suggests that classic hallucinogens have clinically relevant effects, particularly in the case of LSD treatment of alcoholism. In the past decade, clinical trials have resumed investigating the effects of classic hallucinogens in the treatment of existential distress in the face of cancer, and in the treatment of addictions including alcoholism and nicotine addiction. The studies that have been completed to date are not sufficient to establish efficacy, but the outcomes have been very encouraging, and larger trials, up to and including phase 3, are now underway or being planned. Although research has elucidated many of the acute neurobiological and psychological effects of classic hallucinogens on humans, animals, and in vitro systems, the mechanisms of clinically relevant persisting effects remain poorly understood.
Bogenschutz, M. P., & Ross, S. (2016). Therapeutic applications of classic hallucinogens. 10.1007/7854_2016_464
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Psilocybin-Assisted Therapy: A Review of a Novel Treatment for Psychiatric Disorders

Abstract

Recent research suggests that functional connectivity changes may be involved in the pathophysiology of psychiatric disorders. Hyperconnectivity in the default mode network has been associated with psychopathology, but psychedelic serotonin agonists like psilocybin may profoundly disrupt these dysfunctional neural network circuits and provide a novel treatment for psychiatric disorders. We have reviewed the current literature to investigate the efficacy and safety of psilocybin-assisted therapy for the treatment of psychiatric disorders. There were seven clinical trials that investigated psilocybin-assisted therapy as a treatment for psychiatric disorders related to anxiety, depression, and substance use. All trials demonstrated reductions in psychiatric rating scale scores or increased response and remission rates. There were large effect sizes related to improved depression and anxiety symptoms. Psilocybin may also potentially reduce alcohol or tobacco use and increase abstinence rates in addiction, but the benefits of these two trials were less clear due to open-label study designs without statistical analysis. Psilocybin-assisted therapy efficacy and safety appear promising, but more robust clinical trials will be required to support FDA approval and identify the potential role in clinical psychiatry.
Thomas, K., Malcolm, B., & Lastra, D. (2017). Psilocybin-Assisted Therapy: A Review of a Novel Treatment for Psychiatric Disorders. Journal of Psychoactive Drugs, 1-10. 10.1080/02791072.2017.1320734
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A single administration of the hallucinogen, 4-acetoxy-dimethyltryptamine, prevents the shift to a drug-dependent state and the expression of withdrawal aversions in rodents

Abstract

Despite several studies suggesting the therapeutic use of 5-hydroxytryptamine receptors type 2A (5-HT2A) agonists in the treatment of substance use disorders, the neurobiological basis accounting for such effects are still unknown. It has been observed that chronic exposure to drugs of abuse produces molecular and cellular adaptations in ventral tegmental area (VTA) neurons, mediated by brain-derived neurotrophic factor (BDNF). These BDNF-induced adaptations in the VTA are associated with the establishment of aversive withdrawal motivation that leads to a drug-dependent state. Growing evidence suggests that 5-HT2A receptor signaling can regulate the expression of BDNF in the brain. In this study, we observed that a single systemic or intra-VTA administration of a 5-HT2A agonist in rats and mice blocks both the aversive conditioned response to drug withdrawal and the mechanism responsible for switching from a drug-naive to a drug-dependent motivational system. Our results suggest that 5-HT2A agonists could be used as therapeutic agents to reverse a drug dependent state, as well as inhibiting the aversive effects produced by drug withdrawal.
Vargas‐Perez, H., Grieder, T. E., Ting‐A‐Kee, R., Maal‐Bared, G., Chwalek, M., & van der Kooy, D. (2017). A single administration of the hallucinogen, 4‐acetoxy‐dimethyltryptamine, prevents the shift to a drug‐dependent state and the expression of withdrawal aversions in rodents. European Journal of Neuroscience. 10.1111/ejn.13572
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Patient Experiences of Psilocybin-Assisted Psychotherapy: An Interpretative Phenomenological Analysis

The psychological mechanisms of action involved in psilocybin-assisted psychotherapy are not yet well understood. Despite a resurgence of quantitative research regarding psilocybin, the current study is the first qualitative study of participant experiences in psilocybin-assisted psychotherapy. Semistructured interviews were carried out with 13 adult participants aged 22 to 69 years (M = 50 years) with clinically elevated anxiety associated with a cancer diagnosis. Participants received a moderate dose of psilocybin and adjunctive psychotherapy with an emphasis on the process of meaning-making. Verbatim transcribed interviews were analyzed by a five-member research team using interpretative phenomenological analysis. General themes found in all or nearly all transcripts included relational embeddedness, emotional range, the role of music as conveyor of experience, meaningful visual phenomena, wisdom lessons, revised life priorities, and a desire to repeat the psilocybin experience. Typical themes found in the majority of transcripts included the following: exalted feelings of joy, bliss, and love; embodiment; ineffability; alterations to identity; a movement from feelings of separateness to interconnectedness; experiences of transient psychological distress; the appearance of loved ones as guiding spirits; and sharing the experience with loved ones posttreatment. Variant themes found in a minority of participant transcripts include lasting changes to sense of identity, synesthesia experiences, catharsis of powerful emotion, improved relationships after treatment, surrender or “letting go,” forgiveness, and a continued struggle to integrate experience. The findings support the conclusion that psilocybin-assisted psychotherapy may provide an effective treatment for psychological distress in cancer patients. Implications for theory and treatment are discussed.

Belser, A. B., Agin-Liebes, G., Swift, T. C., Terrana, S., Devenot, N., Friedman, H. L., … & Ross, S. (2017). Patient experiences of psilocybin-assisted psychotherapy: An interpretative phenomenological analysis. Journal of Humanistic Psychology, 0022167817706884.
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The Therapeutic Potential of Psychedelic Drugs: Past, Present, and Future

Abstract

Plant-based psychedelics, such as psilocybin, have an ancient history of medicinal use. After the first English language report on LSD in 1950, psychedelics enjoyed a short-lived relationship with psychology and psychiatry. Used most notably as aids to psychotherapy for the treatment of mood disorders and alcohol dependence, drugs such as LSD showed initial therapeutic promise before prohibitive legislature in the mid-1960s effectively ended all major psychedelic research programs. Since the early 1990s, there has been a steady revival of human psychedelic research: last year saw reports on the first modern brain imaging study with LSD and three separate clinical trials of psilocybin for depressive symptoms. In this circumspective piece, RLC-H and GMG share their opinions on the promises and pitfalls of renewed psychedelic research, with a focus on the development of psilocybin as a treatment for depression.
Carhart-Harris, R. L., & Goodwin, G. M. (2017). The Therapeutic Potential of Psychedelic Drugs: Past, Present, and Future. Neuropsychopharmacology. 10.1038/npp.2017.84
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Increased spontaneous MEG signal diversity for psychoactive doses of ketamine, LSD and psilocybin

Abstract

What is the level of consciousness of the psychedelic state? Empirically, measures of neural signal diversity such as entropy and Lempel-Ziv (LZ) complexity score higher for wakeful rest than for states with lower conscious level like propofol-induced anesthesia. Here we compute these measures for spontaneous magnetoencephalographic (MEG) signals from humans during altered states of consciousness induced by three psychedelic substances: psilocybin, ketamine and LSD. For all three, we find reliably higher spontaneous signal diversity, even when controlling for spectral changes. This increase is most pronounced for the single-channel LZ complexity measure, and hence for temporal, as opposed to spatial, signal diversity. We also uncover selective correlations between changes in signal diversity and phenomenological reports of the intensity of psychedelic experience. This is the first time that these measures have been applied to the psychedelic state and, crucially, that they have yielded values exceeding those of normal waking consciousness. These findings suggest that the sustained occurrence of psychedelic phenomenology constitutes an elevated level of consciousness – as measured by neural signal diversity.
Schartner, M. M., Carhart-Harris, R. L., Barrett, A. B., Seth, A. K., & Muthukumaraswamy, S. D. (2017). Increased spontaneous MEG signal diversity for psychoactive doses of ketamine, LSD and psilocybin. Scientific Reports, 7. 10.1038/srep46421
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Pharmacokinetics of Escalating Doses of Oral Psilocybin in Healthy Adults

Abstract

INTRODUCTION: Psilocybin is a psychedelic tryptamine that has shown promise in recent clinical trials for the treatment of depression and substance use disorders. This open-label study of the pharmacokinetics of psilocybin was performed to describe the pharmacokinetics and safety profile of psilocybin in sequential, escalating oral doses of 0.3, 0.45, and 0.6 mg/kg in 12 healthy adults.

METHODS: Eligible healthy adults received 6-8 h of preparatory counseling in anticipation of the first dose of psilocybin. The escalating oral psilocybin doses were administered at approximately monthly intervals in a controlled setting and subjects were monitored for 24 h. Blood and urine samples were collected over 24 h and assayed by a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for psilocybin and psilocin, the active metabolite. The pharmacokinetics of psilocin were determined using both compartmental (NONMEM) and noncompartmental (WinNonlin) methods.

RESULTS: No psilocybin was found in plasma or urine, and renal clearance of intact psilocin accounted for less than 2% of the total clearance. The pharmacokinetics of psilocin were linear within the twofold range of doses, and the elimination half-life of psilocin was 3 h (standard deviation 1.1). An extended elimination phase in some subjects suggests hydrolysis of the psilocin glucuronide metabolite. Variation in psilocin clearance was not predicted by body weight, and no serious adverse events occurred in the subjects studied.

CONCLUSIONS: The small amount of psilocin renally excreted suggests that no dose reduction is needed for subjects with mild-moderate renal impairment. Simulation of fixed doses using the pharmacokinetic parameters suggest that an oral dose of 25 mg should approximate the drug exposure of a 0.3 mg/kg oral dose of psilocybin. Although doses of 0.6 mg/kg are in excess of likely therapeutic doses, no serious physical or psychological events occurred during or within 30 days of any dose.

Brown, R. T., Nicholas, C. R., Cozzi, N. V., Gassman, M. C., Cooper, K. M., Muller, D., … & Hutson, P. R. (2017). Pharmacokinetics of Escalating Doses of Oral Psilocybin in Healthy Adults. Clinical Pharmacokinetics, 1-12. 10.1007/s40262-017-0540-6
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An online survey of tobacco smoking cessation associated with naturalistic psychedelic use

Data suggest psychedelics such as psilocybin and lysergic acid diethylamide (LSD) may hold therapeutic potential in the treatment of addictions, including tobacco dependence. This retrospective cross-sectional anonymous online survey characterized 358 individuals (52 females) who reported having quit or reduced smoking after ingesting a psychedelic in a non-laboratory setting ⩾1 year ago. On average, participants smoked 14 cigarettes/day for 8 years, and had five previous quit attempts before their psychedelic experience. Of the 358 participants, 38% reported continuous smoking cessation after psychedelic use (quitters). Among quitters, 74% reported >2 years’ abstinence. Of the 358 participants, 28% reported a persisting reduction in smoking (reducers), from a mode of 300 cigarettes/month before, to a mode of 1 cigarette/month after the experience. Among reducers, 62% reported >2 years of reduced smoking. Finally, 34% of the 358 participants (relapsers) reported a temporary smoking reduction before returning to baseline smoking levels, with a mode time range to relapse of 3–6 months. Relapsers rated their psychedelic experience significantly lower in personal meaning and spiritual significance than both other groups. Participants across all groups reported less severe affective withdrawal symptoms (e.g. depression, craving) after psychedelic use compared with previous quit attempts, suggesting a potential mechanism of action for psychedelic-associated smoking cessation/reduction. Changes in life priorities/values were endorsed as the most important psychological factor associated with smoking cessation/reduction. Results suggest psychedelics may hold promise in treating tobacco addiction as potentially mediated by spiritual experience, changed priorities/values, and improved emotional regulation.

Johnson, M. W., Garcia-Romeu, A., Johnson, P. S., & Griffiths, R. R. (2017). An online survey of tobacco smoking cessation associated with naturalistic psychedelic use. Journal of Psychopharmacology, 0269881116684335. 10.1177/0269881116684335
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Classic Hallucinogens and Mystical Experiences: Phenomenology and Neural Correlates

Abstract

This chapter begins with a brief review of descriptions and definitions of mystical-type experiences and the historical connection between classic hallucinogens and mystical experiences. The chapter then explores the empirical literature on experiences with classic hallucinogens in which claims about mystical or religious experiences have been made. A psychometrically validated questionnaire is described for the reliable measurement of mystical-type experiences occasioned by classic hallucinogens. Controlled laboratory studies show that under double-blind conditions that provide significant controls for expectancy bias, psilocybin can occasion complete mystical experiences in the majority of people studied. These effects are dose-dependent, specific to psilocybin compared to placebo or a psychoactive control substance, and have enduring impact on the moods, attitudes, and behaviors of participants as assessed by self-report of participants and ratings by community observers. Other studies suggest that enduring personal meaning in healthy volunteers and therapeutic outcomes in patients, including reduction and cessation of substance abuse behaviors and reduction of anxiety and depression in patients with a life-threatening cancer diagnosis, are related to the occurrence of mystical experiences during drug sessions. The final sections of the chapter draw parallels in human neuroscience research between the neural bases of experiences with classic hallucinogens and the neural bases of meditative practices for which claims of mystical-type experience are sometimes made. From these parallels, a functional neural model of mystical experience is proposed, based on changes in the default mode network of the brain that have been observed after the administration of classic hallucinogens and during meditation practices for which mystical-type claims have been made.
Barrett, F. S., & Griffiths, R. R. (2017). Classic Hallucinogens and Mystical Experiences: Phenomenology and Neural Correlates. 10.1007/7854_2017_474
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Chemistry and Structure-Activity Relationships of Psychedelics

Abstract

This chapter will summarize structure-activity relationships (SAR) that are known for the classic serotonergic hallucinogens (aka psychedelics), focusing on the three chemical types: tryptamines, ergolines, and phenethylamines. In the brain, the serotonin 5-HT2Areceptor plays a key role in regulation of cortical function and cognition, and also appears to be the principal target for hallucinogenic/psychedelic drugs such as LSD. It is one of the most extensively studied of the 14 known types of serotonin receptors. Important structural features will be identified for activity and, where possible, those that the psychedelics have in common will be discussed. Because activation of the 5-HT2A receptor is the principal mechanism of action for psychedelics, compounds with 5-HT2A agonist activity generally are quickly discarded by the pharmaceutical industry. Thus, most of the research on psychedelics can be related to activation of 5-HT2A receptors. Therefore, much of the discussion will include not only clinical or anecdotal studies, but also will consider data from animal models as well as a certain amount of molecular pharmacology where it is known.
Nichols, D. E. (2017). Chemistry and Structure–Activity Relationships of Psychedelics. 10.1007/7854_2017_475
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