Psychological and neuropsychological assessment of regular hoasca users

This study (n=57) assessed the socio-economic status, mood, personality traits, impulsiveness, drug use, quality of life, extrinsic and intrinsic religiosity, and neuropsychological function of ayahuasca users and non-users. The findings indicate that religious use of ayahuasca does not adversely affect neuropsychological functioning and may have positive effects on substance abuse and mood.

Abstract

“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.”

Authors: Paulo C. R. Barbosa, Rick J. Strassman, Dartiu Xavier da Silveira, Kelsy Areco, Robert Hoy, Jessica Pommy, Robert Thoma & Michael Bogenschutz

Summary

Psychological and neuropsychological assessment of regular hoasca users

Hoasca is a DMT-containing psychedelic brew used by Amerindian populations of the Amazon Basin. It has been spread to Western societies through syncretic churches.

Hoasca is a decoction made from the bush Psychotria viridis and the liana Banisteriopsis caapi. It contains DMT and the -carboline alkaloids harmine, harmaline, and tetrahydroharmine, which make it orally psychoactive.

Hoasca has acute effects on perceptual, cognitive, affective, and kinesthetic function, and can cause anxiety, nausea, and vomiting. It is also used for magico-religious purposes by Amerindian and Mestizo populations of the western Amazon Basin.

Hoasca-using religious groups have come under scrutiny by regulatory agencies, but their use has been judged more favorably in Brazil and the US Supreme Court has affirmed their right to have their hoasca seized. There are few rigorous studies of long-term safety and/or persisting effects of hoasca. The present research compared the psychological and neuropsychological characteristics of a group of UDV members who drink hoasca regularly during religious services to a group of socio-economic status matched non-hoasca users.

According to official documents, the UDV was founded in 1961 by Jose Gabriel da Costa. Members drink hoasca tea twice a month and practice the religion’s doctrine and teachings both inside and outside of the hoasca ceremonies.

Thirty UDV members and 27 control subjects were evaluated for their exposure to hoasca. All subjects were at least 18 years of age and able to provide informed consent.

UDV subjects were recruited through the congregation of the local UDV church, and control subjects were recruited through public presentations in churches, flyers, and advertisements. Evaluations took place at the Center for Psychiatric Research of the University of New Mexico. The Duke University Religion Index (DUREL) was used to measure subjects s involvement in communal “organizational religious activity” (ORA), non-organizational religious activity (NORA), and intrinsic religiosity (IR). The Daily Spiritual Experience Scale (DSES) was used to measure subjects s spiritual experiences. We administered the Medical Outcomes Study Short Form-36 (SF-36), a 36-item questionnaire to evaluate eight dimensions of quality of life, and the Profile of Mood States (POMS) to assess mood and personality traits. The Barratt Impulsiveness Scale (BIS-11) assessed three domains of impulsivity. We evaluated recent and past use of alcohol and drugs using the Addiction Severity Index, 5th edition, and grouped the remaining substances.

The AMNART is a test that estimates verbal intelligence through pronunciation of 45 irregularly-spelled words. The Trail Making Test and the Stroop Color and Word Test assess speed of visual scanning, psychomotor speed, executive functioning, and cognitive flexibility. The interference score indicates the amount of interference between colors and words. The Conners’ Continuous Performance Test, Second Edition, the California Verbal Learning Test, and the Rey-Osterrieth Complex Figure Test were used to measure sustained attention, verbal retention, retrieval, recognition, and vulnerability to proactive interference.

We used the Shapiro-Wilk test to analyze continuous variables and the Mann-Whitney U test to analyze dichotomous variables. We used the Box-Tidwell procedure to assess the linearity assumption of the independent variables with respect to the logit of the dependent variables. Results Table 1 presents demographic, religious affiliation, masses, services and hoasca ritual attendance data for 30 members of the UDV and 27 control members.

The UDV group had significantly fewer church attendance to rituals and other public religious activities than controls, and scored significantly lower on the Duke Religious Index (DUREL)-assessed Organizational Religious Activity (ORA) scale.

The UDV group scored significantly higher on measures of lifetime past use of alcohol to intoxication and lifetime cannabis use than the control group. We performed logistic regressions to ascertain the effects of total lifetime months of regular attendance at hoasca rituals and the number of hoasca rituals attended during the previous 12 months on ASI-assessed drug use variables. We found that both continuous hoasca attendance rituals independent variables were linearly related to the dependent variables. UDV group had lower scores on depression and confusion scales than control group, and higher scores on role limitations due to physical health item.

The UDV group scored higher on the Big Five Inventory (BFI)-assessed personality factors Agreeableness and Openness than controls, and on the SF-36-assessed Role Limitations due to Physical Health than controls. They were less susceptible to proactive interference during verbal learning than controls.

The UDV group did not differ from controls in multiple neuropsychological measures, including intellectual functioning, attention, memory, visuospatial ability, executive functioning, and fine motor control. They demonstrated healthier scores on self-assessments of current mood state, including less depression and confusion. Substance use and psychological functioning were associated with hoasca ceremonies attended during the previous 12 months but not with total lifetime months of regular attendance at hoasca rituals.

We found that ritual use of hoasca reduces alcohol use and abuse. This is consistent with previous studies that found greater psychiatric health in hoasca-using groups.

The UDV might be contributing to our results because of its stricter attitude towards cannabis use compared to other hoasca groups.

Only past use of alcohol to intoxication was significantly correlated with hoasca ritual attendance, and the UDV group had better scores on measures of mood and personality. This indicates possible selection-bias. Previous studies have demonstrated that hoasca use may involve a powerful combination of experiential processes and pharmacological properties that results in dramatic short-term changes on mood, personality and substance use. According to some studies, hoasca has antidepressant effects, inhibits ethanol-induced locomotion, and prevents ethanol sensitization in mice models. These effects are consistent with qualitative reports from members of the UDV, and with a prospective study found that novice hoasca-church members mood improved after their first session.

The results indicate that there were no differences between groups in verbal memory ability, but that the UDV group achieved better scores on a measure of proactive interference than controls, suggesting that controls were more susceptible to the effects of prior learning when trying to learn new and similar information.

The study found that the groups were equivalent on cognitive tests prior to the UDV group’s use of hoasca, and that there were no differences between the groups on the Stroop, Trail Making Test, Rey-Osterrieth Complex Figure and Connners Continuous Performance Test.

5. Conclusion

In this study, ritual hoasca users demonstrated better scores on mood, personality, and quality of life variables compared to normal controls, and also facilitated cessation of use and abuse of alcohol and cannabis.

This study provides evidence for the safety of long-term hoasca use among UDV members, and indicates several intriguing beneficial effects. Further studies are necessary to address the issue of selection-bias and Type I error.

Acknowledgements

We wish to thank Michael Hunter, Erika Griffiths, Linda A. Schenkel and the religious communities of Albuquerque for their contributions to the study.