OPEN Foundation

D. da Silveira

A phenomenological analysis of the subjective experience elicited by ibogaine in the context of a drug dependence treatment



This report documents the phenomenology of the subjective experiences of 22 patients with substance-related disorders who were involved in a treatment combining cognitive–behavioral therapy and hospital sessions with ibogaine in Brazil.


Participants underwent a one-to-one semi-structured interview exploring the subjective effects of ibogaine. We employed interpretative phenomenological analysis to identify relevant phenomenological categories, including physical sensations, perceptual (visual, auditory, and olfactory), emotional, cognitive, and spiritual. Participants also compared ibogaine with other drugs used in life, including psychedelics like ayahuasca, psilocybin mushrooms, and lysergic acid diethylamide.


The findings reveal that the subjective experience with ibogaine has similarities with other psychedelic substances, but also important differences. These include very strong and unpleasant physical effects as well as, at least in this patient population, a very difficult and challenging experience.


Overall, the descriptions involve heightened memory retrieval, specially related to drug abuse and the perception of one’s own future with or without drug use. Strong perceptual phenomena, especially dreamlike visions, were commonly reported. Based on Revonsuo’s evolutionary hypothesis for the function of dreams and of previous suggestions that ibogaine has oneiric properties, we suggest the subjective experience of drug-dependent patients elicited by ibogaine may be framed as simulations of threat and danger.

Schenberg, E. E., de Castro Comis, M. A., Alexandre, J. F. M., Tófoli, L. F., Chaves, B. D. R., & da Silveira, D. X. (2017). A phenomenological analysis of the subjective experience elicited by ibogaine in the context of a drug dependence treatment. Journal of Psychedelic Studies, (0), 1-10. 10.1556/2054.01.2017.007
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Treating drug dependence with the aid of ibogaine: A qualitative study


Background: Substance use disorders are important contributors to the global burden of disease, but current treatments are not associated with high rates of recovery. The lack of approved and effective treatments is acutely problematic for psychostimulants like cocaine and crack cocaine. One promising alternative in the treatment of drug dependence in general and psychostimulants in particular is the use of the psychedelic alkaloid ibogaine combined with psychotherapy. This was recently shown to induce prolonged periods of abstinence in polydrug users, including psychostimulants. However, drug dependence treatments cannot be comprehensively evaluated with reductions in consumption alone, with current recommendations including secondary outcome measures like craving, family and social relationship, quality of life, and self-efficacy.

Methods: We therefore employed a directed approach to qualitative content analysis to evaluate the outcomes of a treatment combining ibogaine with cognitive-behavioral therapy based on data gathered from patient’s reports obtained in semi-structured interviews.

Main findings: The results revealed that patients benefited from the treatment in all the secondary outcomes, reporting decreases in craving and improvements in personal relationships, quality of life, and self-efficacy, thus supporting existing notions that treatments combining ibogaine and psychotherapy do have a therapeutic potential in the treatment of substance use disorders.

Schenberg, E. E., de Castro Comis, M. A., Alexandre, J. F. M., Chaves, B. D. R., Tófoli, L. F., & da Silveira, D. X. (2016). Treating drug dependence with the aid of ibogaine: A qualitative study. Journal of Psychedelic Studies, (0), 1-10. 10.1556/2054.01.2016.002

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Psychological and neuropsychological assessment of regular hoasca users


BACKGROUND: Hoasca (also called ayahuasca) is a N,N-dimethyltryptamine (DMT) – containing psychedelic brew originally used for magico-religious purposes by Amerindian populations of the Amazon Basin. Recently, Brazilian syncretic churches have helped spread the ritual use of hoasca to Western societies. The aim of this study was to evaluate substance use, and neuropsychological and psychological functioning of regular hoasca users within a religious setting.

METHODS: Assessment of socio-economic status, mood, personality traits, impulsiveness, drug use, quality of life, extrinsic and intrinsic religiosity, and neuropsychological function was performed on 30 volunteers from a U.S. branch of União do Vegetal (UDV), a Brazilian religion which uses hoasca ritually. We also assessed 27 non-hoasca-using control subjects matched by socio-demographic profile and church attendance. Mann-Whitney U, chi-squared and Fisher tests were used to analyze differences between groups. Spearman’s association and simple logistic regression tests were used to analyze the impact of frequency of hoasca use on dependent variables.

RESULTS: Relative to the control group, the UDV group demonstrated lower scores for depression (p=0.043, r=.27) and confusion (p=0.032, r=.29) as assessed by the Profile of Mood States (POMS); higher scores on the instrument Big Five Inventory (BFI) for the personality traits agreeableness (p=0.028, r=.29) and openness (p=0.037, r=.28); higher scores on the quality life domain role limitations due to physical health as determined by the instrument Medical Outcomes Study Short Form-36 – SF-36 (p=0.035, r=.28); less recent use of alcohol (p<0.001, φc=.57), greater past use of alcohol to intoxication (p=0.007, φc=.36) and past use of cannabis (p=0.001, φc=.45) as measured by the Addiction Severity Index (ASI), 5th edition; better score on a measure of memory vulnerability to proactive interference as measured by the California Verbal Learning Test – CVLT (p=0.040, r=.27). Lifetime use of hoasca was positively correlated with role limitations due to physical health (p=0.032, rs=.39) and negatively associated with lifetime heavy alcohol use (p=0.034, OR=0.979).

CONCLUSIONS: The findings indicate that religious use of hoasca does not adversely affect neuropsychological functioning and may have positive effects on substance abuse and mood.

Barbosa, P. C. R., Strassman, R. J., da Silveira, D. X., Areco, K., Hoy, R., Pommy, J., … & Bogenschutz, M. (2016). Psychological and neuropsychological assessment of regular hoasca users. Comprehensive Psychiatry, 71, 95-105. 0.1016/j.comppsych.2016.09.003

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Treating drug dependence with the aid of ibogaine: A retrospective study


Ibogaine is an alkaloid purported to be an effective drug dependence treatment. However, its efficacy has been hard to evaluate, partly because it is illegal in some countries. In such places, treatments are conducted in underground settings where fatalities have occurred. In Brazil ibogaine is unregulated and a combined approach of psychotherapy and ibogaine is being practiced to treat addiction. To evaluate the safety and efficacy of ibogaine, we conducted a retrospective analysis of data from 75 previous alcohol, cannabis, cocaine and crack users (72% poly-drug users). We observed no serious adverse reactions or fatalities, and found 61% of participants abstinent. Participants treated with ibogaine only once reported abstinence for a median of 5.5 months and those treated multiple times for a median of 8.4 months. This increase was statistically significant (p < 0.001), and both single or multiple treatments led to longer abstinence periods than before the first ibogaine session (p < 0.001). These results suggest that the use of ibogaine supervised by a physician and accompanied by psychotherapy can facilitate prolonged periods of abstinence, without the occurrence of fatalities or complications. These results suggest that ibogaine can be a safe and effective treatment for dependence on stimulant and other non-opiate drugs.

Schenberg, E.E., de Castro Comis, M.A., Rasmussen Chaves, B. & da Silveira, D. X. (2014). Treating drug dependence with the aid of ibogaine: A retrospective study. Journal of Psychopharmacology, 28(11), 993-1000.
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Report on psychoactive drug use among adolescents using ayahuasca within a religious context

Ritual use of ayahuasca within the context of the Brazilian ayahuasca churches often starts during late childhood or early adolescence. Premature access to psychoactive drugs may represent a risk factor for drug misuse. Conversely, religious affiliation seems to play a protective role in terms of substance abuse. The objective of this study was to describe patterns of drug use in a sample of adolescents using ayahuasca within a religious setting. Forty-one adolescents from a Brazilian ayahuasca sect were compared with 43 adolescents who never drank ayahuasca. No significant differences were identified in terms of lifetime substance consumption. Throughout the previous year period, ayahuasca adolescents used less alcohol (46.31%) than the comparison group (74.4%). Recent use of alcohol was also more frequent among the latter group (65.1%) than among ayahuasca drinkers (32.5%). Although not statistically significant, slight differences in terms of patterns of drug use were definitely observed among groups. Despite their early exposure to a hallucinogenic substance, adolescents using ayahuasca in a controlled setting were mostly comparable to controls except for a considerably smaller proportion of alcohol users. Religious affiliation may have played a central role as a possible protective factor for alcohol use. Thus, ayahuasca seems to be a relatively safe substance as far as drug misuse is concerned.

Doering-Silveira, E., Grob, C. S., de Rios, M. D., Lopez, E., Alonso, L. K., Tacla, C., & Da Silveira, D. X. (2005). Report on psychoactive drug use among adolescents using ayahuasca within a religious context. Journal of psychoactive drugs, 37(2), 141-144. 10.1080/02791072.2005.10399794
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4 October - Online psychedelic Q&A with Rick Doblin (founder and president of MAPS)