The purpose of this paper is to provide an integrative review and offer novel insights regarding human research with classic psychedelics (classic hallucinogens), which are serotonin 2A receptor (5-HT2AR) agonists such as lysergic acid diethylamide (LSD), mescaline, and psilocybin. Classic psychedelics have been administered as sacraments since ancient times. They were of prominent interest within psychiatry and neuroscience in the 1950s to 1960s, and during this time contributed to the emergence of the field of molecular neuroscience. Promising results were reported for treatment of both end-of-life psychological distress and addiction, and classic psychedelics served as tools for studying the neurobiological bases of psychological disorders. Moreover, classic psychedelics were shown to occasion mystical experiences, which are subjective experiences reported throughout different cultures and religions involving a strong sense of unity, among other characteristics. However, the recreational use of classic psychedelics and their association with the counterculture prompted an end to human research with classic psychedelics in the early 1970s. We provide the most comprehensive review of epidemiological studies of classic psychedelics to date. Notable among these are a number of studies that have suggested the possibility that nonmedical naturalistic (non-laboratory) use of classic psychedelics is associated with positive mental health and prosocial outcomes, although it is clear that some individuals are harmed by classic psychedelics in non-supervised settings. We then review recent therapeutic studies suggesting efficacy in treating psychological distress associated with life-threatening diseases, treating depression, and treating nicotine and alcohol addictions. We also describe the construct of mystical experience, and provide a comprehensive review of modern studies investigating classic psychedelic-occasioned mystical experiences and their consequences. These studies have shown classic psychedelics to fairly reliably occasion mystical experiences. Moreover, classic-psychedelic-occasioned mystical experiences are associated with improved psychological outcomes in both healthy volunteer and patient populations. Finally, we review neuroimaging studies that suggest neurobiological mechanisms of classic psychedelics. These studies have also broadened our understanding of the brain, the serotonin system, and the neurobiological basis of consciousness. Overall, these various lines of research suggest that classic psychedelics might hold strong potential as therapeutics, and as tools for experimentally investigating mystical experiences and behavioral-brain function more generally
Ayahuasca is a hallucinogenic beverage that is prominent in the ethnomedicine and shamanism of indigenous Amazonian tribes. Its unique pharmacology depends on the oral activity of the hallucinogen, N,N-dimethyltryptamine (DMT), which results from inhibition of monoamine oxidase (MAO) by β-carboline alkaloids. MAO is the enzyme that normally degrades DMT in the liver and gut. Ayahuasca has long been integrated into mestizo folk medicine in the northwest Amazon. In Brazil, it is used as a sacrament by several syncretic churches. Some of these organizations have incorporated in the United States. The recreational and religious use of ayahuasca in the United States, as well as “ayahuasca tourism” in the Amazon, is increasing. The current legal status of ayahuasca or its source plants in the United States is unclear, although DMT is a Schedule I controlled substance. One ayahuasca church has received favorable rulings in 2 federal courts in response to its petition to the Department of Justice for the right to use ayahuasca under the Religious Freedom Restoration Act. A biomedical study of one of the churches, the Uñiao do Vegetal (UDV), indicated that ayahuasca may have therapeutic applications for the treatment of alcoholism, substance abuse, and possibly other disorders. Clinical studies conducted in Spain have demonstrated that ayahuasca can be used safely in normal healthy adults, but have done little to clarify its potential therapeutic uses. Because of ayahuasca’s ill-defined legal status and variable botanical and chemical composition, clinical investigations in the United States, ideally under an approved Investigational New Drug (IND) protocol, are complicated by both regulatory and methodological issues. This article provides an overview of ayahuasca and discusses some of the challenges that must be overcome before it can be clinically investigated in the United States.
Background There is growing use of Salvia divinorum (SD), a psychoactive plant that produces hallucinogen-like effects through a kappa opioid receptor (KOR) mechanism. Little is known about KOR agonist effects in humans and about users of SD. Objectives To characterize the reasons, methods, and reported consequences of SD use. Methods Individuals reading SD-related pages of a drug-information website were invited to anonymously complete an online questionnaire if they had used SD. Results Participants (N = 500) were 92.6% male and 23.4 ± 8.7 (mean ± s.d.) years old. They had used a median of six times (range 1–250). 80.6% probably or definitely would use SD again. Most participants (92.6%) typically smoked or vaporized SD product. When smoked, the drug’s main effects were estimated to last 14.1 ± 12.8 (range 0.5–120) minutes. When asked to compare SD effects to other methods of altering consciousness, the most common answer was that SD was unique (38.4%). 25.8% reported persisting (≥24 h) positive effects (often described as increased sense of well-being) on at least one occasion. 4.4% reported persisting negative effects (most often anxiety). Conclusions SD is typically smoked, acute effects are brief, and persistent adverse effects are uncommon. In addition to acute hallucinogenic effects, SD may produce subacute increases in subjective well-being. Such a subacute effect would be unusual for a drug that is used non-medically, as withdrawal from other drugs typically either does not affect mood or causes dysphoria. Findings from this convenience sample should be confirmed and extended using surveys of random samples and controlled clinical studies.
Genus Salvia, commonly known as sage, is the largest genus in the Lamiaceae family. It comprises many species traditionally used as brain-enhancing tonics. In vitro and animal studies have confirmed that several Salvia species contain a large array of active compounds that may enhance cognitive activity and protect against neurodegenerative disease. In this review, the active constituents in plants belonging to the genus Salvia are summarised, and their influence on pharmacodynamics pertinent to cognitive activity are detailed. In particular, the effects of plants belonging to the genus Salvia and their constituents on cognitive skills including memory, attention and learning are detailed. Their potential effects in dementia, including Alzheimer’s disease, are also examined. Completed human trials are summarised, and factors influencing the potency of Salvia plants are covered. Finally, directions for future research are proposed to enhance our understanding of the potential health benefits of Salvia plants. Key Points Salvia plants and their constituents can influence several biological mechanisms associated with cognition including their effects on amyloid-β, cholinergic activity, neurotrophins, oxidative stress, inflammation and anxiolytic/antidepressant behaviours. Several studies have confirmed the many Salvia species have promising, cognitive-enhancing effects in human adults. Further research is required to examine the longer-term cognitive-enhancing effects of Salvia species on cognition, memory and the treatment of neurodegenerative diseases such as Alzheimer’s disease.
It is usually believed that drugs of abuse are smuggled into the United States or are clandestinely produced for illicit distribution. Less well known is that many hallucinogens and dissociative agents can be obtained from plants and fungi growing wild or in gardens. Some of these botanical sources can be located throughout the United States; others have a more narrow distribution. This article reviews plants containing N,N-dimethyltryptamine, reversible type A monoamine oxidase inhibitors (MAOI), lysergic acid amide, the anticholinergic drugs atropine and scopolamine, or the diterpene salvinorin-A (Salvia divinorum). Also reviewed are mescaline-containing cacti, psilocybin/psilocin-containing mushrooms, and the Amanita muscaria and Amanita pantherina mushrooms that contain muscimol and ibotenic acid. Dangerous misidentification is most common with the mushrooms, but even a novice forager can quickly learn how to properly identify and prepare for ingestion many of these plants. Moreover, through the ever-expanding dissemination of information via the Internet, this knowledge is being obtained and acted upon by more and more individuals. This general overview includes information on the geographical range, drug content, preparation, intoxication, and the special health risks associated with some of these plants. Information is also offered on the unique issue of when bona fide religions use such plants as sacraments in the United States. In addition to the Native American Church’s (NAC) longstanding right to peyote, two religions of Brazilian origin, the Santo Daime and the Uniao do Vegetal (UDV), are seeking legal protection in the United States for their use of sacramental dimethyltryptamine-containing “ayahuasca.”
Background Numerous anecdotal reports suggest that repeated use of very low doses of lysergic acid diethylamide (LSD), known as microdosing, improves mood and cognitive function. These effects are consistent both with the known actions of LSD on serotonin receptors and with limited evidence that higher doses of LSD (100–200 μg) positively bias emotion processing. Yet, the effects of such subthreshold doses of LSD have not been tested in a controlled laboratory setting. As a first step, we examined the effects of single very low doses of LSD (0–26 μg) on mood and behavior in healthy volunteers under double-blind conditions. Methods Healthy young adults (N = 20) attended 4 laboratory sessions during which they received 0 (placebo), 6.5, 13, or 26 μg of LSD in randomized order at 1-week intervals. During expected peak drug effect, they completed mood questionnaires and behavioral tasks assessing emotion processing and cognition. Cardiovascular measures and body temperature were also assessed. Results LSD produced dose-related subjective effects across the 3 doses (6.5, 13, and 26 μg). At the highest dose, the drug also increased ratings of vigor and slightly decreased positivity ratings of images with positive emotional content. Other mood measures, cognition, and physiological measures were unaffected. Conclusions Single microdoses of LSD produced orderly dose-related subjective effects in healthy volunteers. These findings indicate that a threshold dose of 13 μg of LSD might be used safely in an investigation of repeated administrations. It remains to be determined whether the drug improves mood or cognition in individuals with symptoms of depression.
Assessments of lysergic acid diethylamide (LSD) in the treatment of alcoholism have not been based on quantitative meta-analysis. Hence, we performed a meta-analysis of randomized controlled trials in order to evaluate the clinical efficacy of LSD in the treatment of alcoholism. Two reviewers independently extracted the data, pooling the effects using odds ratios (ORs) by a generic inverse variance, random effects model. We identified six eligible trials, including 536 participants. There was evidence for a beneficial effect of LSD on alcohol misuse (OR, 1.96; 95% CI, 1.36–2.84; p = 0.0003). Between-trial heterogeneity for the treatment effects was negligible (I2 = 0%). Secondary outcomes, risk of bias and limitations are discussed. A single dose of LSD, in the context of various alcoholism treatment programs, is associated with a decrease in alcohol misuse.
Post-traumatic stress disorder (PTSD) presents a major public health problem for which currently available treatments are modestly effective. We report the findings of a randomized, double-blind, placebo-controlled, multi-site phase 3 clinical trial (NCT03537014) to test the efficacy and safety of 3,4-methylenedioxymethamphetamine (MDMA)-assisted therapy for the treatment of patients with severe PTSD, including those with common comorbidities such as dissociation, depression, a history of alcohol and substance use disorders, and childhood trauma. After psychiatric medication washout, participants (n = 90) were randomized 1:1 to receive manualized therapy with MDMA or with placebo, combined with three preparatory and nine integrative therapy sessions. PTSD symptoms, measured with the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5, the primary endpoint), and functional impairment, measured with the Sheehan Disability Scale (SDS, the secondary endpoint) were assessed at baseline and at 2 months after the last experimental session. Adverse events and suicidality were tracked throughout the study. MDMA was found to induce significant and robust attenuation in CAPS-5 score compared with placebo (P < 0.0001, d = 0.91) and to significantly decrease the SDS total score (P = 0.0116, d = 0.43). The mean change in CAPS-5 scores in participants completing treatment was −24.4 (s.d. 11.6) in the MDMA group and −13.9 (s.d. 11.5) in the placebo group. MDMA did not induce adverse events of abuse potential, suicidality or QT prolongation. These data indicate that, compared with manualized therapy with inactive placebo, MDMA-assisted therapy is highly efficacious in individuals with severe PTSD, and treatment is safe and well-tolerated, even in those with comorbidities. We conclude that MDMA-assisted therapy represents a potential breakthrough treatment that merits expedited clinical evaluation.
The success of modern medicine creates a growing population of those suffering from life-threatening illnesses (LTI) who often experience anxiety, depression, and existential distress. We present a novel approach; investigating MDMA-assisted psychotherapy for the treatment of anxiety in people with an LTI. Participants with anxiety from an LTI were randomized in a double-blind study to receive MDMA (125 mg, n = 13) or placebo (n = 5) in combination with two 8-h psychotherapy sessions. The primary outcome was change in State-Trait Anxiety Inventory (STAI) Trait scores from baseline to one month post the second experimental session. After unblinding, participants in the MDMA group had one open-label MDMA session and placebo participants crossed over to receive three open-label MDMA sessions. Additional follow-up assessments occurred six and twelve months after a participant’s last experimental session. At the primary endpoint, the MDMA group had a greater mean (SD) reduction in STAI-Trait scores, − 23.5 (13.2), indicating less anxiety, compared to placebo group, − 8.8 (14.7); results did not reach a significant group difference (p = .056). Hedges’ g between-group effect size was 1.03 (95% CI: − 5.25, 7.31). Overall, MDMA was well-tolerated in this sample. These preliminary findings can inform development of larger clinical trials to further examine MDMA-assisted psychotherapy as a novel approach to treat individuals with LTI-related anxiety.
Rationale: 3,4-Methylenedioxymethamphetamine (MDMA) mainly releases serotonin (5-HT) and is contained in the recreational drug Ecstasy. 5-HT is known to play an important role in mood and anxiety disorders, for which there is a female preponderance. To date, there are no systematic data on gender differences in the subjective effects of MDMA. Objectives: The present work analyzed the pooled data from three controlled studies on the psychological and physiological effects of MDMA in healthy volunteers with no or minimal MDMA experience. A particular focus of the analyses were possible gender differences. Methods: A total of 74 subjects (54 male, 20 female) participated in all three studies. MDMA in oral doses ranging from 70–150 mg (1.35–1.8 mg/kg) was administered under double-blind placebo-controlled conditions. Subjective peak changes were assessed by standardized psychometric rating scales. Physiological measures were blood pressure, heart rate, and peripheral body temperature. Adverse drug effects were assessed during the experimental session and after 24 h. Results: Psychoactive effects of MDMA were more intense in women than in men. Women especially had higher scores for MDMA-induced perceptual changes, thought disturbances, and fear of loss of body control. The dose of MDMA positively correlated with the intensity of perceptual changes in women. Acute adverse effects and sequelae were also more frequent in female than in male subjects. In contrast, men showed higher increases in blood pressure than woman. Conclusions: The fact that equal doses of MDMA per kilogram body weight produce stronger responses in women compared to men is consistent with an increased susceptibility of women to the 5-HT-releasing effects of MDMA. Our results also indicate that increasing doses of MDMA produce more hallucinogen-like perceptual alterations, particularly in women.