Ayahuasca is a botanical hallucinogen traditionally used for therapeutic and ritual purposes by indigenous groups from Northwestern Amazonian countries such as Brazil, Peru, Colombia, and Ecuador. Ayahuasca is made by the decoction of two plants, which are rich in the 5-HT1A/2A partial agonist dimethyltryptamine or DMT (from the leaves of the Psychotria viridis bush) and β-carbolines such as harmine, from the stalks of the Banisteriopsis caapi vine. There is an increasing interest in the possible therapeutic effects of ayahuasca, especially for psychiatric disorders (major depression, posttraumatic stress disorder, and substance use disorder). This review summarizes information on the pharmacology, safety, and therapeutic potentials of ayahuasca. Although human experimental and naturalist studies published until now suggest a good safety and tolerability profile, often associated with improvements in depressive and anxious symptoms, there are few controlled studies, with small sample sizes, using only single doses, and with short follow-ups. Potential benefits of ayahuasca should be evaluated in larger samples in both experimental and observational studies and using different doses in controlled trials.

Evidence suggests that psychedelics bring about their therapeutic outcomes in part through the subjective or qualitative effects they engender and how the individual interprets the resulting experiences. However, psychedelics are contraindicated for individuals who have been diagnosed with certain mental illnesses, on the grounds that these subjective effects may be disturbing or otherwise counter-therapeutic. Substantial resources are therefore currently being devoted to creating psychedelic substances that produce many of the same biological changes as psychedelics, but without their characteristic subjective effects. In this article, we consider ethical issues arising from the prospect of such potential “nonsubjective” psychedelics. We are broadly supportive of efforts to produce such substances for both scientific and clinical reasons. However, we argue that such nonsubjective psychedelics should be reserved for those special cases in which the subjective effects of psychedelics are specifically contraindicated, whereas classic psychedelics that affect subjective experience should be considered the default and standard of care. After reviewing evidence regarding the subjective effects of psychedelics, we raise a number of ethical concerns around the prospect of withholding such typically positive, meaningful, and therapeutic experiences from most patients.

Recent absorbed residue studies have confirmed that ceramic and shell containers were used for consuming Datura in precolumbian times. Until now, no one has identified what tools precolumbian people used to produce a concentrated hallucinogenic concoction. In this study, we used mass spectrometry to identify Datura residues (a flowering plant with hallucinogenic properties) in two late precolumbian composite bottles from the Central Arkansas River valley. Unlike the construction of most Mississippian bottles, the bottles in this study are unique because ceramic disks with a series of concentric perforations were incorporated in the bottles at the juncture of the bottle neck with the globular portion of the body. The organic residue analysis revealed Datura residues in both bottles. We argue that the internal clay disks served as strainers that allowed Datura producers to separate the hallucinogenic alkaloids from the Datura flower to produce a powerful liquid beverage.

Se analizan las redes de tráfico de la Quebrada de Humahuaca en tiempos del “fenómeno Isla”, evaluando críticamente el protagonismo atribuido a Tiwanaku en su organización. Con este fin se presentan las investigaciones realizadas en Muyuna —uno de los principales sitios de la época en la Quebrada— ofreciendo información novedosa sobre contextos domésticos y funerarios, economía y modo de vida. Un análisis bayesiano de todas las dataciones disponibles para el componente Isla lo ubican entre fines del siglo once y comienzos del siglo catorce dC. Estos resultados, junto con el probable origen de los bienes presentes en estos contextos, llevan a concluir que las interacciones con otras regiones de los Andes circumpuneños fueron más importantes para los procesos de diferenciación social en las comunidades Isla que las relaciones con el estado Tiwanaku. En este marco, cobran especial relevancia la relación con el Río Grande de San Juan y la gravitación de ciertos colectivos supra-regionales (pastores, consumidores de alucinógenos) que podrían introducir una dimensión heterárquica en la organización de las redes sur andinas.

Clinical evidence suggests that hallucinogenic drug-induced altered states of consciousness (ASCs) and the incipient, acute stages of endogenous psychoses share many common phenomenological features. The aim of our study was to assess hallucinogen-like phenomena in endogenous psychotic patients using standardised methods. We examined 93 endogenous psychotic patients, 50 healthy controls and a small group of drug induced psychotic patients (n = 7) with two ASC self-assessment scales (questionnaire APZ = Abnormer Psychischer Zustand = Altered State of Consciousness [Dittrich et al, 1985]; and questionnaire OAV = Abbreviation of the three subscales: Oceanic Boundlessness/Angst = Dread of Ego Dissolution/Visionary Restructuralisation [Bodmer 1989]). Patients were examined shortly after remission of their last acute psychotic episode and they answered the questionnaires referring to the early phase of this episode. Differences in the questionnaire scores were significant between psychotic patients and controls. Drug induced patients had numerically higher scores than endogenous psychotic patients, however these differences were only significant for the APZ total score and the undifferentiated items of the APZ, but not for the three APZ subscale and the OAV scores. More than 50% of the endogenous psychotic patients answered 26% of the APZ-and 43% of the OAV-items with “yes”. The OAV total score and the OSE (Ozeanische Selbstentgrenzung = oceanic boundlessness) scores of both questionnaires correlated significantly with BPRS Factor 3 (thought disturbance). Our results support the hypothesis that hallucinogen-like experiences represent common phenomena during the acute stages of endogenous psychoses. Remarkably, these phenomena include subjectively pleasant experiences of the OSE dimension. In the routine clinical assessment of endogenous psychotic patients experiences of this dimension may be more easily overlooked than the negative experiences of the AIA dimension (AIA: Angst vor der Ich-Auflösung = dread of ego dissolution).

We describe a 38-year-old woman who developed symptoms of hallucinogen persisting perception disorder (HPPD) after using lysergic acid diethylamide (LSD) once and continued to have symptoms of HPPD for nearly 17 years, although she did not use LSD after her first use. The symptoms of HPPD were temporally related to her first LSD use and she responded well to risperidone within a few weeks of commencing on the same. Although different medications have been tried in the management of HPPD including risperidone, olanzapine, clonidine, fluoxetine, sertraline, benzodiazepines and anti-epileptic medications, none have been proven to be the definitive medication of choice in the treatment of HPPD. Furthermore, there have been case reports suggesting worsening of symptoms with risperidone; however, the response to risperidone in our patient suggests the possibility of its effectiveness in the management of HPPD symptoms in some patients.

After an interruption of almost 20 years, psychopharmacological research on hallucinogenic drugs was revived in several countries simultaneously around 1990. Most of the projects that have been initiated since then have been based on the conception of model psychosis: by administering hallucinogens to healthy test subjects, psychiatrists induce a state regarded as an artificial and temporary psychosis, which can be studied under controlled experimental conditions in the laboratory. As a model of psychosis, the hallucinogen intoxication is meant to provide important clues to schizophrenia research. This article examines the history of the concept and practice of model psychosis in order to demarcate the peculiarities of its most recent articulation in the vocabulary of cognitive neuroscience. It highlights the shift from phenomenological to biological psychiatry. The analysis contributes to an understanding of the ‘regional epistemology’ of psychopharmacology by reflecting on the question: what kind of a model is the hallucinogen model of psychosis?