Rafael G. dos Santos

Antidepressant effects of a single dose of ayahuasca in patients with recurrent depression: a preliminary report

OBJECTIVES Ayahuasca (AYA), a natural psychedelic brew prepared from Amazonian plants and rich in dimethyltryptamine (DMT) and harmine, causes effects of subjective well-being and may therefore have antidepressant actions. This study sought to evaluate the effects of a single dose of AYA in six volunteers with a current depressive episode. METHODS Open-label trial conducted in an inpatient psychiatric unit. RESULTS Statistically significant reductions of up to 82% in depressive scores were observed between baseline and 1, 7, and 21 days after AYA administration, as measured on the Hamilton Rating Scale for Depression (HAM-D), the Montgomery-Åsberg Depression Rating Scale (MADRS), and the Anxious-Depression subscale of the Brief Psychiatric Rating Scale (BPRS). AYA administration resulted in nonsignificant changes in Young Mania Rating Scale (YMRS) scores and in the thinking disorder subscale of the BPRS, suggesting that AYA does not induce episodes of mania and/or hypomania in patients with mood disorders and that modifications in thought content, which could indicate psychedelic effects, are not essential for mood improvement. CONCLUSIONS These results suggest that AYA has fast-acting anxiolytic and antidepressant effects in patients with a depressive disorder.

Autonomic, neuroendocrine, and immunological effects of ayahuasca: a comparative study with d-amphetamine.

Ayahuasca is an Amazonian psychotropic plant tea combining the 5-HT2A agonist N,N-dimethyltryptamine (DMT) and monoamine oxidase-inhibiting &bgr;-carboline alkaloids that render DMT orally active. The tea, obtained from Banisteriopsis caapi and Psychotria viridis, has traditionally been used for religious, ritual, and medicinal purposes by the indigenous peoples of the region. More recently, the syncretistic religious use of ayahuasca has expanded to the United States and Europe. Here we conducted a double-blind randomized crossover clinical trial to investigate the physiological impact of ayahuasca in terms of autonomic, neuroendocrine, and immunomodulatory effects. An oral dose of encapsulated freeze-dried ayahuasca (1.0 mg DMT/kg body weight) was compared versus a placebo and versus a positive control (20 mg d-amphetamine) in a group of 10 healthy volunteers. Ayahuasca led to measurable DMT plasma levels and distinct subjective and neurophysiological effects that were absent after amphetamine. Both drugs increased pupillary diameter, with ayahuasca showing milder effects. Prolactin levels were significantly increased by ayahuasca but not by amphetamine, and cortisol was increased by both, with ayahuasca leading to the higher peak values. Ayahuasca and amphetamine induced similar time-dependent modifications in lymphocyte subpopulations. Percent CD4 and CD3 were decreased, whereas natural killer cells were increased. Maximum changes occurred around 2 hours, returning to baseline levels at 24 hours. In conclusion, ayahuasca displayed moderate sympathomimetic effects, significant neuroendocrine stimulation, and a time-dependent modulatory effect on cell-mediated immunity. Future studies on the health impact of long-term ayahuasca consumption should consider the assessment of immunological status in regular users.

Antidepressive, anxiolytic, and antiaddictive effects of ayahuasca, psilocybin and lysergic acid diethylamide (LSD): a systematic review of clinical trials published in the last 25 years

To date, pharmacological treatments for mood and anxiety disorders and for drug dependence show limited efficacy, leaving a large number of patients suffering severe and persistent symptoms. Preliminary studies in animals and humans suggest that ayahuasca, psilocybin and lysergic acid diethylamide (LSD) may have antidepressive, anxiolytic, and antiaddictive properties. Thus, we conducted a systematic review of clinical trials published from 1990 until 2015, assessing these therapeutic properties. Electronic searches were performed using the PubMed, LILACS, and SciELO databases. Only clinical trials published in peer-reviewed journals were included. Of these, 151 studies were identified, of which six met the established criteria. Reviewed studies suggest beneficial effects for treatment-resistant depression, anxiety and depression associated with life-threatening diseases, and tobacco and alcohol dependence. All drugs were well tolerated. In conclusion, ayahuasca, psilocybin and LSD may be useful pharmacological tools for the treatment of drug dependence, and anxiety and mood disorders, especially in treatment-resistant patients. These drugs may also be useful pharmacological tools to understand psychiatric disorders and to develop new therapeutic agents. However, all studies reviewed had small sample sizes, and half of them were open-label, proof-of-concept studies. Randomized, double-blind, placebo-controlled studies with more patients are needed to replicate these preliminary findings.

Safety and Side Effects of Ayahuasca in Humans—An Overview Focusing on Developmental Toxicology

Abstract Despite being relatively well studied from a botanical, chemical, and (acute) pharmacological perspective, little is known about the possible toxic effects of ayahuasca (an hallucinogenic brew used for magico-ritual purposes) in pregnant women and in their children, and the potential toxicity of long-term ayahuasca consumption. It is the main objective of the present text to do an overview of the risks and possible toxic effects of ayahuasca in humans, reviewing studies on the acute ayahuasca administration to humans, on the possible risks associated with long-term consumption by adults and adolescents, and on the possible toxic effects on pregnant animals and in their offspring. Acute ayahuasca administration, as well as long-term consumption of this beverage, does not seem to be seriously toxic to humans. Although some nonhuman developmental studies suggested possible toxic effects of ayahuasca or of some of its alkaloids, the limited human literature on adolescents exposed to ayahuasca as early as in the uterus reports no serious toxic effects of the ritual consumption of the brew. Researchers must take caution when extrapolating nonhuman data to humans and more data are needed in basic and human research before a definite opinion can be made regarding the possible toxic effects of ayahuasca in pregnant women and in their children.Abstract Despite being relatively well studied from a botanical, chemical, and (acute) pharmacological perspective, little is known about the possible toxic effects of ayahuasca (an hallucinogenic brew used for magico-ritual purposes) in pregnant women and in their children, and the potential toxicity of long-term ayahuasca consumption. It is the main objective of the present text to do an overview of the risks and possible toxic effects of ayahuasca in humans, reviewing studies on the acute ayahuasca administration to humans, on the possible risks associated with long-term consumption by adults and adolescents, and on the possible toxic effects on pregnant animals and in their offspring. Acute ayahuasca administration, as well as long-term consumption of this beverage, does not seem to be seriously toxic to humans. Although some nonhuman developmental studies suggested possible toxic effects of ayahuasca or of some of its alkaloids, the limited human literature on adolescents exposed to ayahuasca as earl...

A Critical Evaluation of Reports Associating Ayahuasca with Life-Threatening Adverse Reactions

Abstract Ayahuasca is a botanical hallucinogenic preparation traditionally consumed by Northwestern Amazonian indigenous groups. Scientific evidence suggests good tolerability after acute administration of ayahuasca and also after years or even decades of its ritual consumption. Nevertheless, some scientific and media reports associate ayahuasca or some of its alkaloids with severe intoxications. The purpose of the present text is to do a critical evaluation of these reports. The evaluation of the cases highlights the fact that some lack accurate forensic/toxicological information, while others are not directly relevant to traditional ayahuasca preparations. These limitations reduce the possibility of an accurate risk assessment, which could indicate potential contraindications and susceptibilities for ayahuasca consumption. Nevertheless, even with these limitations, the cases suggest that previous cardiac and hepatic pathologies and current use of serotonergic drugs/medications are contraindications to ayahuasca use, and that caution should be taken when using different botanical species and extracted/synthetic alkaloids to prepare ayahuasca analogues.Abstract Ayahuasca is a botanical hallucinogenic preparation traditionally consumed by Northwestern Amazonian indigenous groups. Scientific evidence suggests good tolerability after acute administration of ayahuasca and also after years or even decades of its ritual consumption. Nevertheless, some scientific and media reports associate ayahuasca or some of its alkaloids with severe intoxications. The purpose of the present text is to do a critical evaluation of these reports. The evaluation of the cases highlights the fact that some lack accurate forensic/toxicological information, while others are not directly relevant to traditional ayahuasca preparations. These limitations reduce the possibility of an accurate risk assessment, which could indicate potential contraindications and susceptibilities for ayahuasca consumption. Nevertheless, even with these limitations, the cases suggest that previous cardiac and hepatic pathologies and current use of serotonergic drugs/medications are contraindications to a...

Antidepressive and anxiolytic effects of ayahuasca: a systematic literature review of animal and human studies.

Objective: To conduct a systematic literature review of animal and human studies reporting anxiolytic or antidepressive effects of ayahuasca or some of its isolated alkaloids (dimethyltryptamine, harmine, tetrahydroharmine, and harmaline). Methods: Papers published until 3 April 2015 were retrieved from the PubMed, LILACS and SciELO databases following a comprehensive search strategy and using a predetermined set of criteria for article selection. Results: Five hundred and fourteen studies were identified, of which 21 met the established criteria. Studies in animals have shown anxiolytic and antidepressive effects of ayahuasca, harmine, and harmaline, and experimental studies in humans and mental health assessments of experienced ayahuasca consumers also suggest that ayahuasca is associated with reductions in anxiety and depressive symptoms. A pilot study reported rapid antidepressive effects of a single ayahuasca dose in six patients with recurrent depression. Conclusion: Considering the need for new drugs that produce fewer adverse effects and are more effective in reducing anxiety and depression symptomatology, the described effects of ayahuasca and its alkaloids should be further investigated.

The current state of research on ayahuasca: A systematic review of human studies assessing psychiatric symptoms, neuropsychological functioning, and neuroimaging

Rationale: In recent decades, the use of ayahuasca (AYA) – a β-carboline- and dimethyltryptamine-rich hallucinogenic botanical preparation traditionally used by Northwestern Amazonian tribes for ritual and therapeutic purposes – has spread from South America to Europe and the USA, raising concerns about its possible toxicity and hopes of its therapeutic potential. Thus, it is important to analyze the acute, subacute, and long-term effects of AYA to assess its safety and toxicity. Objectives: The purpose of this study was to conduct a systematic review of human studies assessing AYA effects on psychiatric symptoms, neuropsychological functioning, and neuroimaging. Methods: Papers published until 16 December 2015 were included from PubMed, LILACS and SciELO databases following a comprehensive search strategy and pre-determined set of criteria for article selection. Results: The review included 28 full-text articles. Acute AYA administration was well tolerated, increased introspection and positive mood, altered visual perceptions, activated frontal and paralimbic regions and decreased default mode network activity. It also improved planning and inhibitory control and impaired working memory, and showed antidepressive and antiaddictive potentials. Long-term AYA use was associated with increased cortical thickness of the anterior cingulate cortex and cortical thinning of the posterior cingulate cortex, which was inversely correlated to age of onset, intensity of prior AYA use, and spirituality. Subacute and long-term AYA use was not associated with increased psychopathology or cognitive deficits, being associated with enhanced mood and cognition, increased spirituality, and reduced impulsivity. Conclusions: Acute, subacute, and long-term AYA use seems to have low toxicity. Preliminary studies about potential therapeutic effects of AYA need replication due to their methodological limitations.

Effects of Ayahuasca and its Alkaloids on Drug Dependence: A Systematic Literature Review of Quantitative Studies in Animals and Humans

ABSTRACT Recently, the anti-addictive potential of ayahuasca, a dimethyltryptamine(DMT)- and β-carboline-rich hallucinogenic beverage traditionally used by indigenous groups of the Northwest Amazon and currently by syncretic churches worldwide, has received increased attention. To better evaluate this topic, we performed a systematic literature review using the PubMed database to find quantitative studies (using statistical analysis) that assessed the effects of ayahuasca or its components in drug-related symptoms or disorders. We found five animal studies (using harmaline, harmine, or ayahuasca) and five observational studies of regular ayahuasca consumers. All animal studies showed improvement of biochemical or behavioral parameters related to drug-induced disorders. Of the five human studies, four reported significant reductions of dependence symptoms or substance use, while one did not report significant results. The mechanisms responsible for the anti-addictive properties of ayahuasca and its alkaloids are not clarified, apparently involving both peripheral MAO-A inhibition by the β-carbolines and central agonism of DMT at 5-HT2A receptors expressed in brain regions related to the regulation of mood and emotions. Although results are promising, controlled studies are needed to replicate these preliminary findings.

Assessment of the Psychotherapeutic Effects of Ritual Ayahuasca Use on Drug Dependency: A Pilot Study

Using personality, psychopathology, and neuropsychological assessment instruments, our team assessed the therapeutic effects of an ayahuasca ritual treatment. Data was collected at the Institute of Applied Amazonian Ethnopsychology (IDEAA), in the Brazilian Amazon Basin. Psychological assessments were obtained both before and at the end of the treatment. The ayahuasca treatment lasted between 3 and 9 months and included biweekly ayahuasca consumption. The sample consisted of 13 patients (8 men, 5 women) with a mean age of 35 years. Nine had a diagnosis of drug abuse and/or dependence; one of borderline personality disorder, and 3 were at IDEAA for personal growth. Results showed that the “Impulsiveness,” “Disorderliness,” “Anticipatory Worry,” and “Shyness with Strangers” subscales of the Temperament and Character Inventory presented statistically significant reductions after treatment, while the “Self-Directedness,” “Responsibility,” “Purposefulness,” and “Congruent Second Nature” subscales presented significant increases. The psychopathology subscales “Positive Symptoms,” “Obsessive–Compulsive,” and “Anxiety” of the Symptom Check-List-90-Revised, were significantly diminished after treatment, as well as all subscales of the Frontal Systems Behavior Scale: “Total,” “Apathy,” “Disinhibition,” and “Executive Dysfunction.” In addition, the “Resistance to Interference” measure of the Stroop Color and Word Test, the Purpose in Life Test, and the “Transcendent Dimension,” “Meaning and Purpose in Life,” “Mission in Life,” and “Material Values” subscales of the Spiritual Orientation Inventory presented statistically significant increases after treatment. Despite important limitations, such as the small sample size and the lack of a control group, the present pilot study provides preliminary evidence suggesting psychotherapeutic effects of ritual ayahuasca treatment in drug-related disorders.

Ayahuasca, dimethyltryptamine, and psychosis: a systematic review of human studies:

Ayahuasca is a hallucinogen brew traditionally used for ritual and therapeutic purposes in Northwestern Amazon. It is rich in the tryptamine hallucinogens dimethyltryptamine (DMT), which acts as a serotonin 5-HT2A agonist. This mechanism of action is similar to other compounds such as lysergic acid diethylamide (LSD) and psilocybin. The controlled use of LSD and psilocybin in experimental settings is associated with a low incidence of psychotic episodes, and population studies corroborate these findings. Both the controlled use of DMT in experimental settings and the use of ayahuasca in experimental and ritual settings are not usually associated with psychotic episodes, but little is known regarding ayahuasca or DMT use outside these controlled contexts. Thus, we performed a systematic review of the published case reports describing psychotic episodes associated with ayahuasca and DMT intake. We found three case series and two case reports describing psychotic episodes associated with ayahuasca intake, and three case reports describing psychotic episodes associated with DMT. Several reports describe subjects with a personal and possibly a family history of psychosis (including schizophrenia, schizophreniform disorders, psychotic mania, psychotic depression), nonpsychotic mania, or concomitant use of other drugs. However, some cases also described psychotic episodes in subjects without these previous characteristics. Overall, the incidence of such episodes appears to be rare in both the ritual and the recreational/noncontrolled settings. Performance of a psychiatric screening before administration of these drugs, and other hallucinogens, in controlled settings seems to significantly reduce the possibility of adverse reactions with psychotic symptomatology. Individuals with a personal or family history of any psychotic illness or nonpsychotic mania should avoid hallucinogen intake.