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ORIGINAL RESEARCH
published: 24 April 2018
doi: 10.3389/fpsyt.2018.00136
Frontiers in Psychiatry | www.frontiersin.org 1April 2018 | Volume 9 | Article 136
Edited by:
Andrew Robert Gallimore,
Okinawa Institute of Science and
Technology, Japan
Reviewed by:
Vijay Arjun Ramchandani,
National Institute on Alcohol Abuse
and Alcoholism, United States
Santiago J. Ballaz,
Yachay Tech University, Ecuador
*Correspondence:
Paulo Cesar Ribeiro Barbosa
pcrbarbosa@uesc.br
†Retired.
Specialty section:
This article was submitted to
Neuropharmacology,
a section of the journal
Frontiers in Psychiatry
Received: 22 December 2017
Accepted: 29 March 2018
Published: 24 April 2018
Citation:
Barbosa PCR, Tófoli LF,
Bogenschutz MP, Hoy R, Berro LF,
Marinho EAV, Areco KN and
Winkelman MJ (2018) Assessment of
Alcohol and Tobacco Use Disorders
Among Religious Users of Ayahuasca.
Front. Psychiatry 9:136.
doi: 10.3389/fpsyt.2018.00136
Assessment of Alcohol and Tobacco
Use Disorders Among Religious
Users of Ayahuasca
Paulo Cesar Ribeiro Barbosa 1
*, Luís F. Tófoli2, Michael P. Bogenschutz 3, Robert Hoy 4,
Lais F. Berro 5, Eduardo A. V. Marinho 6, Kelsy N. Areco 7and Michael J. Winkelman 8†
1Department of Philosophy and Human Sciences, Universidade Estadual de Santa Cruz, Ilhéus, Brazil, 2Department of
Medical Psychology and Psychiatry, Faculty of Medical Sciences, Universidade Estadual de Campinas, Campinas, Brazil,
3New York School of Medicine, New York, NY, United States, 4University of New Mexico, Simpson Hall, Albuquerque, NM,
United States, 5Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS,
United States, 6Department of Health Sciences, Universidade Estadual de Santa Cruz, Ilhéus, Brazil, 7Departamento de
Psiquiatria, Universidade Federal de São Paulo, São Paulo, Brazil, 8School of Human Evolution and Social Change, Arizona
State University, Tempe, AZ, United States
The aims of this study were to assess the impact of ceremonial use of ayahuasca—a
psychedelic brew containing N,N-dimethyltryptamine (DMT) and β-carboline —and
attendance at União do Vegetal (UDV) meetings on substance abuse; here we report
the findings related to alcohol and tobacco use disorder. A total of 1,947 members of
UDV 18+years old were evaluated in terms of years of membership and ceremonial
attendance during the previous 12 months. Participants were recruited from 10 states
from all major regions of Brazil. Alcohol and tobacco use was evaluated through
questionnaires first developed by the World Health Organization and the Substance
Abuse and Mental Health Services Administration. Analyses compared levels of alcohol
and tobacco use disorder between the UDV and a national normative sample (n=
7,939). Binomial tests for proportions indicated that lifetime use of alcohol and tobacco
was higher in UDV sample compared to the Brazilian norms for age ranges of 25–34
and over 34 years old, but not for the age range of 18–24 years old. However, current
use disorders for alcohol and tobacco were significantly lower in the UDV sample than
the Brazilian norms. Regression analyses revealed a significant impact of attendance at
ayahuasca ceremonies during the previous 12 months and years of UDV membership
on the reduction of alcohol and tobacco use disorder.
Keywords: ayahuasca, hoasca, União do Vegetal, alcohol, tobacco, substance use disorder
INTRODUCTION
Alcohol and tobacco substance-related disorders and health consequences are a major public health
problem. The World Health Organization [1] estimated that the global prevalence of alcohol
use disorder (AUD) in 2010 was 4.1%, including alcohol dependence (2.3%) and harmful use
of alcohol (1.8%). The WHO also estimated that 3.3 million (or 5.9%) of 2012 global deaths
were attributable to alcohol use. Alcohol causes or negatively impacts several health conditions,
including neuropsychiatric impairment, gastrointestinal diseases, cancers, cardiovascular diseases,
and fetal and birth complications [1]. Tobacco related health conditions such as cancer,
cardiovascular diseases, and respiratory system diseases account for 12% of deaths of people aged
30 and over around the globe [2].
Barbosa et al. Ayahuasca and Alcohol and Tobacco Use Disorder
Despite the substantial amount of resources that official
organizations invest in programs to prevent substance use
and its adverse consequences, substance-related problems are
still a major public health issue across the globe [1,3,4].
Current treatment options for alcohol and tobacco disorders
include an impressive diversity of pharmacological, psychosocial,
and technological resources that are nonetheless only partially
effective [5–8]. Consequently further investigations are needed
to explore and evaluate new strategies to prevent and treat
substance-related disorders.
During the last two decades evidence has emerged that
suggests that ayahuasca, a psychedelic brew containing N,N-
dimethyltryptamine (DMT) and β-carboline, has effective
properties to reduce substance abuse. Originally used for magico-
religious purposes by Amerindian populations of the Amazon
Basin, modern syncretic forms of ritual ayahuasca use have
spread to major Brazilian cities and to many other countries.
Currently ayahuasca is used within formal religions, such as
União do Vegetal (UDV), Santo Daime, and Barquinha; in a
worldwide distribution of “vegetalistas,” particularly from Peru;
as well as in religious-independent contexts, such as ayahuasca
retreats.
The first rigorous evidence that ayahuasca could have positive
effects on substance-related problems was published by Grob
et al. [9], who reported the absence of current drug/alcohol-
related problems in a sample of UDV members (where ayahuasca
is referred to as hoasca). They used the Composite International
Diagnostic Interview (CIDI) to assess 15 adult long-term UDV
members and 15 non-ayahuasca-user controls. Interestingly,
this research found evidence for past diagnostic criteria for
alcohol use disorders (AUD) for 5 UDV members who no
longer met the criteria after becoming UDV members. In
comparison, only one control subject showed past and no
longer active AUD diagnosis. Accordingly, Doering-Silveira et al.
[10] found lower past month and past year alcohol use in 41
adolescents who were ayahuasca users from the UDV compared
to 43 matched control adolescents with no previous ayahuasca
exposure. Another research group administered the Addiction
Severity Index 5th Edition (ASI-5) and found lower recent use
of alcohol among 127 adult ayahuasca users from the Santo
Daime and Barquinha relative to 75 non-ayahuasca users [11].
A recent study administered the ASI-5 to compare substance
use among 30 UDV ayahuasca users with 27 non-ayahuasca
users who were active members of Catholic and Protestant
churches [12]. Relative to the control group, the UDV group
demonstrated greater past use of alcohol to intoxication and past
use of cannabis, but less recent use of alcohol. In a cross-sectional
evaluation of 32 Santo Daime members with no control group,
Halpern et al. [13] administered the Structured Clinical Interview
for DSM-IV psychiatric disorders and detected an individual
with marijuana dependence in partial remission and another
subject with ongoing marijuana abuse. However, 22 participants
with a previous history of drug/alcohol-related problems were
in full remission. Thomas et al. [14] conducted a prospective
study of 12 participants with substance-use related problems
who attended an ayahuasca retreat and subsequently reported
decreased cocaine, tobacco and alcohol use. Finally, Lawn et al.
[15] conducted a cross-sectional survey with 527 participants
who had used ayahuasca in the past year. Their participants
ingested ayahuasca in settings as diverse as a “Healing centre,”
“Retreat,” “Ceremony,” “Church,” “Santo Daime,” “Teacher,”and
“Trained Facilitator.” Out of the 527 participants, 192 were using
ayahuasca for the first time. The authors compared ayahuasca
users with users of other psychedelics (a group who had used
psychedelic mushrooms and LSD, but not ayahuasca, in the last
year, n=18,138) and with non-psychedelic users (a group who
had no exposure to ayahuasca, LSD or psychedelic mushrooms
in the last year, n=78,236). Using the Alcohol Use Disorder
Identification Test (AUDIT) as a measure, the authors reported
less problematic use of alcohol in the ayahuasca-using group
during the past year than reported by the other psychedelic
group, but more problematic use of alcohol in the ayahuasca
group than the non-psychedelic using respondents.
In order to contribute to the literature on the potential
therapeutic effects of religious ayahuasca use on substance use
disorder, the present study investigated substance use patterns
among a much larger sample of ayahuasca users than those of
the aforementioned studies. We recruited volunteers who were
members of the UDV from 10 Southern, Southeastern, Central,
Northeastern, and Northern Brazilian States. The prevalence
of alcohol and tobacco use and disorder in the UDV sample
was analyzed in comparison with the prevalence in a Brazilian
normative sample. We also evaluated the association of alcohol
and tobacco use and disorders with years of UDV membership
and ayahuasca ceremonial attendance during the previous 12
months.
Background Information: União do Vegetal
The União do Vegetal (UDV) has been as described as a “Brazilian
ayahuasca religion”, which also includes other groups such as
Santo Daime, Barquinha and other groups that use ayahuasca in
their ceremonies [16,17]. The religious use of ayahuasca is legal
in Brazil and loosely regulated by the Brazilian government [17–
19]. The UDV is known for its greater organizational capacity
and mobilization relative to the other ayahuasca religions. It
has a book edited by a sociologist member [20] and a Scientific
Commission that analyzes, and in some cases (such as in
the present study), authorizes and provides logistic support to
studies done in the institution. In 2012, there were estimated
to be approximately 16,500 UDV members in South and North
America and Europe. In addition to the ritual use of ayahuasca,
these religions subscribe to Christian principles, as well as
beliefs regarding reincarnation. The UDV is especially restrictive
regarding the use of alcohol, tobacco, and illicit substances.
The ayahuasca consumed by the members of the group is
under formal ritualized conditions. Special ceremonies are held
to prepare the ayahuasca, where the two officially recognized
ingredients—the bark of the Banisteriopsis caapi vine and the
leaves of Psychotria species are boiled together in water. Regular
ayahuasca sessions (escala) open to all members and invited
visitors are held twice a month, but higher ranking members
(mestres, conselheiros, and corpo instructivo) may drink the brew
more frequently in additional closed meetings (see [21] for
additional details).
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Barbosa et al. Ayahuasca and Alcohol and Tobacco Use Disorder
The ayahuasca-induced modification of consciousness is
thought to stimulate spiritual growth, moral development and
the evolution of consciousness, embodied in their motto “Light,
Peace and Love.” Regular ceremonies start at 8:00 p.m. with
the attendees approaching the leader (mestre) in an order of
rank, waiting in line to individually receive a dose in a glass
(150–250 ml). The amount of ceremonial doses received by each
participant is determined by the mestre, in consultations with
senior members, particularly those who personally know the
person; these consultations are generally via short utterances
or non-verbal signs. Attendees may also be queried regarding
their preferred dose or if they want more. The preaching occurs
through mestre sermons, questions directed to the preacher
by the participants to the mestre, through popular songs with
moral contents played on stereo equipment and also through
hymns performed by single participants. During some periods
silence predominates (see [21] for additional details). An optional
additional dose of the brew is available until 10 PM. A short
break occurs approximately 3 ½ h into the ceremony, with a brief
return to conclude the approximately 4 h ceremony by midnight.
The ceremony is followed by consumption of a light meal and
socializing that may last for hours.
METHODS
Design
A cross-sectional study surveyed 1,947 UDV volunteers between
March 2009 and August 2011. Participants were recruited from
35 UDV temples of 10 Brazilian states from the Country’s five
major administrative areas: Amazon and Pará states (North);
Bahia and Ceará states (Northeast); Mato Grosso, Mato Grosso
do Sul, Goiás and Distrito Federal states (Central); São Paulo state
(Southeast); and Santa Catarina (South). Efforts were made to
exhaustively survey the members attending the church during the
activities on a single day at each local.
Recruitment Procedures
Firstly, we obtained a preliminary authorization from UDV
central leadership and approval from UDV Scientific Committee
to conduct the survey in its local temples. The UDV’s Scientific
Committee (Comissão Científica da UDV) and Medical Scientific
Department (Departamento Medico Científico—DEMEC) then
contacted local UDV temples to explain the study goals and
gather a list of volunteers. Volunteers could choose to fill
out hard copy or online versions of the questionnaires. We
code numbered the volunteers‘list so that personal names were
separated from questionnaires in order to assure confidentiality
and anonymity. Church attendees received envelopes and
questionnaires according to their ID number. The members were
informed about the survey by the local officers of the DEMEC,
who explained to them that participation in the study was
voluntary, i.e., only those who wanted to participate in the survey
should fill out the questionnaires. Those who opted for the online
version received an ID number to insert in the corresponding
field of the questionnaire website. Both the electronic and hard
paper versions of the questionnaire contained a cover letter
explaining the aims of the study and the consent form that
explained the voluntary nature of their participation; it also
explained the confidentiality and anonymity of the volunteer’s
information, and the planned assessment on substance use
disorder. The volunteers who agreed to participate signed two
copies of the consent form and mailed one to the researchers in
a postage-paid envelope provided. The study was approved by
the Universidade Federal de Santa Catarina Committees on the
Ethics of Human Research (Process #244/08 FR - 216544).
Instruments
Socio-Economic Variables
Age, sex, years of education, and marital and employment status
were solicited.
Church Membership and Patterns of Ayahuasca Use
This questionnaire evaluated several dimensions concerning the
frequency of ritual attendance during the previous 12 months and
the total years of UDV membership.
SAMHSA-Assessed Substance Use Disorder and
WHO Criteria
The data for our comparison group for alcohol and tobacco
use disorder was based on the II Household Survey on
the use of psychotropic drugs in Brazil: 2005 [22]. This
survey was conducted by the Centro Brasileiro de Informações
sobre Drogas Psicotrópicas (CEBRID) of the Universidade
Federal de São Paulo (UNIFESP) and the Secretaria Nacional
Antidrogas (SENAD), the Brazilian federal agency responsible for
coordinating actions of the national drug policy. This household
survey assessed a sample of 7,939 subjects throughout Brazil
to estimate the Brazilian prevalence of substance use disorders
(SUD) in four age ranges: 12–17, 18–25, 26–34, and over 34
years old. The SUD was assessed by using a Brazilian version
of the Substance Abuse and Mental Health Services (SAMHSA)
[23,24] questionnaire [22]. The questionnaire has six questions
regarding: (1) the length of time spent to get the drug or for
recovering from its effects; (2) substance use in larger quantities
or more often than intended; (3) tolerance (i.e., need to use larger
doses of the drug in order to experience the same effect); (4)
physical risks (e.g., driving and swimming under the effect of the
drug); (5) personal problems (e.g., family and work problems);
and (6) the desire to diminish or cease the use of the drug.
Positive answers to two or more these questions would indicate
the presence of the substance use disorder.
We also administered the alcohol and tobacco sections of
a questionnaire based on the WHO Research and Reporting
Project on the Epidemiology of Drug Dependence [25]. The
questionnaire has been adapted for Brazilians [26,27] and
extensively used for the evaluation of patterns of drug use
among Brazilian students [28]. The instrument is a self-
report questionnaire containing multiple-choice questions about
lifetime drug use and during the last 12 months and last month.
Participants who answer positively to lifetime use of a specific
drug (i.e., if they were exposed to the substance at least once in
their lifetime) were asked about its at least once use during the
last 12 months; those who answer positively to the use in the last
12 months are then asked about its use during the past month. In
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Barbosa et al. Ayahuasca and Alcohol and Tobacco Use Disorder
addition, we added a question regarding substance use during the
year before joining UDV.
In addition to the use of alcohol and tobacco reported here,
SAMHSA and WHO questionnaires also assessed the use of other
substances, including marijuana, hallucinogens, and cocaine.
Our report on the use of these other substances among UDV
members is underway.
Statistical Analyses
Statistical analyses were performed using IBM SPSS 20.0 for
Windows. Binomial tests for proportions were used to assess the
difference between the UDV sample and Brazilian norms for
lifetime use of substances and SAMSHA criteria of substance
use disorder. We tested the difference between the Brazilian
normative sample and the whole UDV sample, as well as
comparison of the Brazilian norms with a subsample of UDV
members who had been active members of the religion for more
than 3 years. Hierarchical logistic regression was used to assess
the prediction of the ayahuasca ceremony attendance variables
on dichotomous dependent variables regarding SAMSHA criteria
for substance disorder and use of substances during the previous
30 days and previous 12 months. The first model included
age, gender and level of education as explanatory variables.
The second model added ayahuasca ritual attendance variables,
which were the frequency of ayahuasca ceremonies during the
previous 12 months and a binary variable regarding years of
church membership, distinguishing members with up to 3 years
of UDV membership from members with more than 3 years of
UDV membership. The decision to transform the continuous
variable years of UDV membership into a binary variable resulted
from preliminary graphical analyses, which demonstrated that
the cut-off point of 3 years of membership would have more
explanatory power in the logistic models. Multi-colinearity of
independent variables was assessed via Pearson’ and Spearman’s
rho correlation matrixes and Variance Inflation Factor (VIF). We
set potential co-linearity problems values of 0.7 for Pearson’ and
Spearman’s correlations and over 10 for VIF. Level of significance
for variables contributing to the model was set at p<0.05.
RESULTS
Sociodemographic Profile
The respondents were predominantly from the central, south and
southeast regions of Brazil (68.7%). They had a mean age of 39.85
years (range 18–81) and were evenly distributed between males
(50.8%) and females (49.2%). The majority of the respondents
(68.4%) were married or in a stable relationship. They had a
mean of 9.44 years of UDV membership and a mean of 34.99
ceremonies attended within the last year (see Tables 1,2for
details).
Comparison Between UDV Sample and
Brazilian Norms for Lifetime Use of Alcohol
and Tobacco
Binomial tests for proportions indicated that lifetime use of
alcohol and tobacco was higher in the UDV sample compared to
the Brazilian norms for age ranges of 25–34 and over 34 years old,
TABLE 1 | Sociodemographic variables.
AGE
Mean (St. Dev) 39.85 (SD =12.078)
Median 38.00
Min- Max 18–81
N1,902
NValid%
NUMBER OF SUBJECTS
Men 982 50.8
Women 952 49.2
Total 1,934 100.0
DEGREE OF EDUCATION
<Bachelor’s 907 47.2
>Bachelor’s 1,013 52.8
Total 1920 100.0
MARITAL STATUS
Single/Never been married 447 23.1
Stable cohabiting with partner 278 14.4
Married 1,043 54.0
Separated/Divorced 134 6.9
Widow 29 1.5
Total 1,931 100.0
EMPLOYMENT STATUS
Student 215 11.3
Employed 458 24.1
Public Servant 404 21.3
Self-employed 479 25.2
Stay-at-Home 139 7.3
Employer 126 6.6
Unemployed 14 0.7
Retired 66 3.5
Total 1,901 100.0
BRAZILIAN GEOGRAPHIC AREAS
Central area: Mato Grosso do
Sul, Mato Grosso, Goiás, Distrito
Federal
674 34.6
South and Southeast areas: São
Paulo, Santa Catarina
663 34.1
Northeast area: Ceará, Bahia 342 17.6
North area: Pará, Amazonas 267 13.7
Total 1,946 100.0
but not for the age range of 18–24 years old. All differences were
statistically significant (p<0.001), except for the comparison
between lifetime tobacco use for the age range of 18–24 years old
(Table 3).
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Barbosa et al. Ayahuasca and Alcohol and Tobacco Use Disorder
TABLE 2 | Ayahuasca ritual attendance variables.
N(valid %) Mean St. Dev. Median Min Max
Years of UDV membership 1,765 9.4486 7.716 7.25 0.01 41.42
≤3 years 372 (21.1%)
>3 years 1,393 (78.9%)
Frequency of ayahuasca
ritual attendance during the
previous 12months
1,772 34.99 12.714 34.00 3 120
Days abstinent from
ayahuasca
1,868 6.92 8.253 5.00 0 120
TABLE 3 | Lifetime use of alcohol and tobacco.
Age range UDV Brasil p O.R.
% (a) % (b)
ALCOHOL
18–24 72.2 78.6 0.029 0.71
25–34 86.6 79.5 <0.001 1.66
≥35 87.7 75.0 <0.001 2.39
TOBACCO
18–24 34.9 39.5 0.126 0.82
25–34 52.8 40.8 <0.001 1.62
≥35 61.3 52.6 <0.001 1.43
Comparison Between the UDV Sample and
the Brazilian Norms for Current Alcohol
and Tobacco Use Disorder
UDV sample showed significantly lower prevalence of alcohol
and tobacco use disorder compared to the Brazilian norms for all
age ranges. When Brazilian norms were compared with the UDV
subsample with more than 3 years of UDV membership, those
differences were of a larger magnitude (Table 4).
Hierarchical Logistic Regressions for
Alcohol Use
Table 5 shows the results for the hierarchical logistic regression
analyzes for alcohol use variables. There was no evidence of
multicollinearity for any of the logistic regression models, as
assessed by VIF greater than 10, nor evidence of multicollinearity
as assessed by Pearson’s and Spearman’s correlations greater than
0.7. The covariates age, gender and level of education included
in the first model (Model 1) explained very little of the variance
of alcohol use during the previous 12 months (2.2%; p=0.001)
and previous 30 days (2.8%; p=0.009), and a little more of the
variance of alcohol use disorder (7%; p=0.001). Gender did not
significantly contribute to the first model (model 1) for any of
the alcohol variables. Age was negatively associated (OR: 0.974,
95% CI 0.959 to 0.989; p=0.001) with use of alcohol during
the previous 12 months, whereas having a Bachelor’s degree
was positively associated (OR: 1.555, 95% CI 1.090 to 2.219; p
=0.015) with the use of alcohol during this period. Having a
Bachelor’s degree was also positively associated with the use of
TABLE 4 | Current alcohol and tobacco use disorder.
Age range UDV Brasil p O.R.
% (a) % (b)
ALCOHOL
18–24 4.9 19.2 <0.001 0.22
25–34 2.3 14.7 <0.001 0.14
≥35 1.0 10.4 <0.001 0.08
ALCOHOL—UDV SUBSAMPLE 3 YEARS MEMBERSHIP
18–24 3.4 19.2 <0.001 0.15
25–34 0,5 14.7 <0.001 0.03
≥35 0.2 10.4 <0.001 0.02
TOBACCO
18–24 2.4 9.4 <0.001 0.24
25–34 2.5 9.4 <0.001 0.24
≥35 0.9 12.2 <0.001 0.06
TOBACCO—UDV SUBSAMPLE 3 YEARS MEMBERSHIP
18–24 1.6 9.4 <0.001 0.16
25–34 1.1 9.4 <0.001 0.10
≥35 0.4 12.2 <0.001 0.03
alcohol during the previous 30 days (OR: 2.599, 95% CI 1.394 to
4.846; p=0.003), and age was negatively associated with alcohol
use disorder (OR: 0.918, 95% CI 0.874 to 0.965; p=0.001).
The inclusion of ayahuasca ritual attendance variables in the
second model (Model 2, see Table 5) increased the explanation
of variance in alcohol use in the previous 12 months (NagR² =
20.5%, 1=18.3%; p<0.001), the variance explained alcohol
use during the previous 30 days (NagR² =18.3%, 1=15.5%;
p<0.001), and the variance explained in alcohol use disorder
(NagR² =18.4%, 1=11.4%; p<0.001). The more the members
attended UDV sessions during the previous 12 months, the less
likely they were to have used alcohol during the previous 12
months (OR: 0.936, 95% CI 0.917 to 0.954; p<0.001), during
the previous 30 days (OR: 0.907, 95% CI 0.880 to 0.936; p<
0.001) or meet the criteria for alcohol use disorder (OR: 0.946,
95% CI 0.904 to 0.991; p=0.018). Participants with more than 3
years of UDV membership were less likely to use alcohol during
the previous 12 months (OR: 0.226, 95% 0.154 to 0.332; p<
0.001), during the previous 30 days (OR: 0.401, 95% 0.221 to
0.727; p=0.003) or to meet criteria for alcohol use disorder
(OR: 0.169, 95% 0.062 to 0.464; p=0.001) than the participants
with 3 years or less of UDV membership. In Models 2, having
a Bachelor’s degree increased the likelihood of using alcohol
during the previous 12 months (OR: 1.760, 95% 1.202 to 2.578;
p=0.003) and during the previous 30 days (OR: 2.819, 95%
1.479 to 5.374; p=0.002) in comparison to those members
without bachelor’s degree. Age was also negatively associated with
criteria for alcohol use disorder (OR: 0.946, 95% 0.900 to 0.993;
p=0.026).
Hierarchical Logistic Regressions for
Tobacco Use
The covariates age, gender and level of education explained
1% (p=0.292) of tobacco use in the previous 12 months,
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Barbosa et al. Ayahuasca and Alcohol and Tobacco Use Disorder
TABLE 5 | Hierarchical logistic regressions for alcohol use.
ALCOHOL USE DURING THE PREVIOUS 12 MONTHS
Model 1 Model 2
(N=1,575; No =1,426; Yes =149) (N=1,562; No =1,420; Yes =142)
OR (95% CI) Sig. OR (95% CI) Sig.
Variables
Age 0.974 (0.959–0.989) 0.001 0.991 (0.975–1.007) 0.266
Gender 0.871 (0.619–1.226) 0.430 0.755 (0.523–1.090) 0.133
Degree of Education >Bachelor’s 1.555 (1.090–2.219) 0.015 1.791 (1.222–2.626) 0.003
Ceremonial attendance during the previous 12 months 0.936 (0.917–0.954) <0.001
Membership >3 years 0.226 (0.154–0.332) <0.001
Model summary
Na R²0.022 0.205
1R²– 0.183
ALCOHOL USE DURING THE PREVIOUS 30 DAYS
Model 1 Model 2
(N=1,572; No =1,517; Yes =55) (N=1,570; No =1,516; Yes =54)
OR (95% CI) Sig. OR (95% CI) Sig.
Variables
Age 0.982 (0.958–1.006) 0.148 0.993 (0.968–1.018) 0.566
Gender 0.817 (0.474–1.408) 0.468 0.648 (0.366–1.150) 0.139
Degree of Education >Bachelor’s 2.599 (1.394–4.846) 0.003 2.819 (1.479–5.374) 0.002
Ceremonial attendance during the previous 12 months 0.907 (0.880–0.936) <0.001
Membership >3 years 0.401 (0.221–0.727) 0.003
Model summary
Na R²0.028 0.183
1R²– 0.155
ALCOHOL USE DISORDER
Model 1 Model 2
(N=1,559; No =1,536; Yes =23) (N=1,559; No =1,536; Yes =23)
OR (95% CI) Sig. OR (95% CI) Sig.
Variables
Age 0.918 (0.874–0.965) 0.001 0.946 (0.900–0.993) 0.026
Gender 0.949 (0.413–2.180) 0.902 0.854 (0.364–2.007) 0.718
Degree of Education >Bachelor’s 0.977 (0.417–2.291) 0.957 1.071 (0.446–2.571) 0.878
Ceremonial attendance during the previous 12 months 0.946 (0.904–0.991) 0.018
Membership >3 years 0.169 (0.062–0.464) 0.001
Model summary
Na R²0.070 0.184
1R²– 0.114
Na, Nagelkerke.
1.2% (p=0.488) of its use during the previous 30 days,
and 0.6% (p=0.745) of tobacco use disorder. None of these
three variables significantly contributed to any of Model 1
analyses (Table 6). The Model 2 analyses with inclusion of
ritual attendance measures (see Table 6) increased the variance
explained in tobacco use during the previous 12 months (NagR²
=11.6%, 1=10.6%; p<0.001), the variance explained in the
use of tobacco during the previous 30 days (NagR² =8.6%, 1
=7.4%; p=0.004) and the variance explained in tobacco use
disorder (NagR² =9.1%, 1=8.5%; p=0.002). Attendance at
UDV ceremonies during the previous 12 months was negatively
correlated with tobacco use in the same period (OR: 0.944, 95%
CI 0.914 to 0.975; p<0.001), negatively correlated with tobacco
use during the previous 30 days (OR: 0.951, 95% CI 0.908 to
0.996; p=0.033) and negatively correlated with tobacco use
disorder (OR: 0.950, 95% CI 0.908 to 0.995; p=0.029). Members
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Barbosa et al. Ayahuasca and Alcohol and Tobacco Use Disorder
TABLE 6 | Hierarchical logistic regressions for tobacco use during the previous 12 months, previous 30 days and tobacco use disorder.
TOBACCO USE DURING THE PREVIOUS 12 MONTHS
Model 1 Model 2
(N=1,581; No =1,536; Yes =45) (N=1,581; No =1,536; Yes =45)
OR (95% CI) Sig. OR (95% CI) Sig.
Variables
Age 0.990 (0.965–1.016) 0.459 1.006 (0.980–1.032) 0.666
Gender 0.656 (0.355–1.213) 0.179 0.593 (0.315–1.113) 0.104
Degree of Education >Bachelor’s 0.749 (0.410–1.369) 0.348 0.790 (0.426–1.465) 0.454
Ceremonial attendance during the previous 12 months 0.944 (0.914–0.975) <0.001
Membership >3 years 0.279 (0.145–0.536) <0.001
Model summary
Na R²0.010 0.116
1R²– 0.106
TOBACCO USE DURING THE 30 DAYS
Model 1 Model 2
(N=1,576; No =1,556; Yes =20) (N=1,576; No =1,556; Yes =20)
OR (95% CI) Sig. OR (95% CI) Sig.
Variables
Age 1.020 (0.984–1.056) 0.285 1.032 (0.996–1.068) 0.080
Gender 0.745 (0.301–1.842) 0.524 0.703 (0.279–1.768) 0.453
Degree of Education >Bachelor’s 0.645 (0.264–1.579) 0.337 0.676 (0.273–1.678) 0.399
Ceremonial attendance during the previous 12 months 0.951 (0.908–0.996) 0.033
Membership >3 years 0.308 (0.118–0.809) 0.017
Model summary
Na R²0.012 0.086
1R²– 0.074
TOBACCO USE DISORDER
Model 1 Model 2
(N=1,573; No =1,552; Yes =21) (N=1,573; No =1,552; Yes =21)
OR (95% CI) Sig. OR (95% CI) Sig.
Variables
Age 0.987 (0.950–1.025) 0.489 1.004 (0.967–1.041) 0.853
Gender 1.207 (0.507–2.871) 0.671 1.132 (0.468–2.738) 0.783
Degree of Education >Bachelor’s 0.741 (0.309–1.778) 0.502 0.777 (0.319–1.892) 0.578
Ceremonial attendance during the previous 12 months 0.950 (0.908–0.995) 0.029
Membership >3 years 0.258 (0.100–0.667) 0.005
Model summary
Na R²0.006 0.091
1R²– 0.085
Na, Nagelkerke.
with more than 3 years of UDV membership were less likely to
have used tobacco during the previous 12 months (OR: 0.279,
95% 0.145 to 0.536; p<0.001), less likely to have used tobacco
during the previous 30 days (OR: 0.308, 95% CI 0.118 to 0.809; p
=0.017) and less likely to meet criteria for tobacco use disorder
(OR: 0.258, 95% 0.100 to 0.667; p=0.005) than the members with
three years or less of membership in the UDV.
DISCUSSION
In this study, the largest survey done with ayahuasca
users to date, we found that UDV sample had remarkably
lower rates of alcohol and tobacco use disorder relative to
Brazilian norms, and that this difference was even greater
when Brazilian normative sample was compared with the
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Barbosa et al. Ayahuasca and Alcohol and Tobacco Use Disorder
ayahuasca subsample with more than 3 years UDV membership.
We also found that ayahuasca use variables—ceremonial
attendance during the previous 12 months and years of UDV
membership—were much stronger predictors of reduced alcohol
and tobacco use disorders and use during the previous 12
months than were the SES variables age, gender and level of
education.
Interestingly, the members of the UDV sample with more than
24 years of age had much greater lifetime exposure to tobacco
and alcohol than the Brazilian normative sample. This finding
is consistent with previous assessments of ayahuasca users, who
have shown less current drug-related problems compared to
controls, but more lifetime exposure to drugs [9,11,12]. This
result, combined with the regression findings of the effect on
ritual ayahuasca ceremonial attendance variables on lowering
alcohol and tobacco use disorder, strongly support the hypothesis
that ritual use of ayahuasca can have powerful therapeutic effects
in addressing drug dependence problems.
The finding of Lawn et al. [15] that ayahuasca users
had greater AUDIT-assessed problematic drinking than non-
psychedelic users is a major exception to the emerging pattern
of the negative association between ayahuasca intake and
substance disorder [9–13]. This discrepancy may be due to
the social support system provided by church membership,
and suggests that the regularity of the use of ayahuasca
within structured settings like UDV and Santo Daime play a
important role in therapeutic and protective effects observed
in the previous studies. In contrast, Lawn’s et al. study
included occasional ayahuasca users who took it in much
more independent contexts (shamans, healers, retreats) than
structured religious contexts, which may have influenced their
less positive results. Furthermore, the UDV has a very restrict
attitude toward alcohol and tobacco use, which may involve
temporary interdiction of more advanced members who abuse
these substances.
Religious variables are widely known for their strong
protective and therapeutic effects on drug use and drug-
related problems [29,30]. The design of the current
research does not allow for analyses the separate the effects
of religious attendance from the pharmacological effects
of ayahuasca on our positive findings. However previous
studies suggest that the pharmacological effects of ayahuasca,
rather than just the social dimensions of church support
for sobriety, contributed substantially to these significant
findings. This strictly pharmacological effect is suggested
by a case-control study that found that UDV members had
lower recent use of alcohol than a control group formed
by active Christian church members [12]. Further support
for strictly pharmacological mechanisms comes from a
experimental study using animal models which found that
ayahuasca inhibits ethanol-induced locomotion and prevents
ethanol sensitization in mice [31]. Others suggest that the
pharmacological mechanisms of the anti-addictive effects of
ayahuasca involve mesolimbic dopaminergic pathways that
are thought to underlie human craving and compulsive use of
abused substances [32].
Possible Pharmacological Mechanisms of
Ayahuasca’s Protective Effects Against
Substance Abuse Disorders
A variety of studies on ayahuasca-based substance abuse
rehabilitation programs provide evidence of treatment efficacy
(e.g., see [33–36]; also see [37] for review), although these studies
fall short of the ideal double-blind clinical designs [38]. The
constituents of ayahuasca provide a variety of physiological
mechanisms by which it may reduce drug dependency (see
[37,38] for review). The therapeutic potential of ayahuasca
in reducing addictive behaviors is likely mediated by the
neurochemical aspects of both of its active components, DMT
and β-carboline, that exert psychoactive properties in both
humans and animals [39–41]. The classic pharmacokinetic
model of ayahuasca involves the β-carboline alkaloids’ inhibition
of the biodegradation of DMT by monoamine oxidase A
(MAO-A) in the gastrointestinal tract [42,43]. By inhibiting
monoamine oxidase, the β-carbolines allow DMT to reach
systemic circulation in the central nervous system and exert its
psychoactive effects. Furthermore, recent studies have shown
that even β-carboline alkaloids alone can exert some therapeutic
effects that lead to decreases in drug abuse-related behaviors
in animal models (for review, see [41]). Thus, ayahuasca’s
complex and unique pharmacological profile provides multiple
mechanisms through which it may exercise direct therapeutic
effects for the treatment of drug dependence.
Liester and Prickett ([44]; also see [45]) propose that the
treatment of the biochemical dynamics of addiction requires
two effects, the first one on serotonin and the second one
on dopamine. An increase in overall serotonin levels is first
necessary to increase dopamine to levels sufficient to attenuate
withdrawal symptoms. Subsequently there needs a normalization
of dopamine levels that can be produced by inhibitory effects
of serotonin on the mesolimbic dopamine pathways’ release
of dopamine. Liester and Prickett ([44,45]) propose that
ayahuasca produces both of these effects through a variety
mechanisms, providing a neurochemical normalization therapy
through pathways that both raise and modulate dopamine in the
mesolimbic dopamine pathway (MDP), remedying addiction by
first releasing sufficient dopamine to normalize dopamine levels,
but then exerting an inhibitory influence that precludes an abrupt
spiking in dopamine that can contribute to liability to addiction.
Because both DMT and β-carbolines are known to modulate
brain serotonergic neurotransmission [41,46,47], the effects
of ayahuasca on drug abuse may reflect the actions of its
components at serotonin receptors. More specifically, DMT
and β-carbolines appear to exert agonistic activity at serotonin
5-HT2A and 5-HT2C receptors [41,46,47]. Due to their
distribution in the brain, 5-HT2A receptor activation increases
dopamine levels in the nucleus accumbens (NAcc) [48], the main
neurochemical effect by which drugs with abuse potential exert
reinforcing and rewarding properties in animals and humans
[49].
Based on this DMT-mediated effect on dopamine levels,
ayahuasca would be expected to have abuse liability in humans.
However, a literature review on ayahuasca has indicated that
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Barbosa et al. Ayahuasca and Alcohol and Tobacco Use Disorder
consumption of traditional preparations in social settings carries
a minimal risk of abuse potential or dependence formation [50].
The lack of abuse liability, as well as the growing evidence of a
therapeutic utility of ayahuasca for the treatment of drug abuse,
further indicates that other mechanisms also play an important
role in the psychoactive effects of ayahuasca. Of note, in contrast
to what is observed with 5-HT2A receptor activation, 5-HT2C
receptor agonists decrease NAcc dopamine levels [48], thereby
antagonizing the dopamine-related effects of 5-HT2A receptor
activation. In fact, 5-HT2C receptor agonists have been recently
proposed as possible therapeutic targets for the treatment of drug
addiction, including ethanol abuse [51–53].
This second anti-dependence mechanism of ayahuasca
constituents is hypothesized to derive from the effects of the
beta-carboline alkaloids that stimulate the release of dopamine
in presynaptic neurons, consequently causing the release of
both dopamine and serotonin in the MDP [44,45]. While
harmine can stimulate the release of dopamine, it also blocks
dopamine reuptake into neurons at the synaptic membranes.
Furthermore, DMT agonism action at the sigma-1 receptor
receptors inhibits dopamine release, resulting in decreases in
the dopamine spiking effects that reinforce addiction. These
combined effects of ayahuasca constituents on MDP dopamine
levels achieves a balance between the dopamine deficiencies that
produce withdrawal symptoms and the spikes in dopamine levels
that contribute to the formation of dependency.
Thus, because DMT and β-carbolines have been proposed to
activate both receptor subtypes, a unique pattern of activation of
5-HT2A/2C receptors seems to underlie the therapeutic effects
of ayahuasca and its lack of abuse liability. This dual action
underlies the potential of ayahuasca as a therapy for drug-
dependence through these combined effects on the MDP that
are considered to be the common pathway underlying most if
not all addictive drugs. The action of the beta-carbolines may
also lead to increases serotonin levels through inhibition of MAO
enzymes, blocking the enzymatic metabolism of catecholamines,
and leading to augmentation of dopamine levels [45]. It is
important to note, however, that both DMT and β-carbolines
also interact with other non-serotonergic molecular targets, and a
possible contribution of those to the effects of ayahuasca on drug
abuse cannot be ruled out [41,54].
The concept of neuroplasticity, the ability of neurons to
alter their synaptic connections, provides additional physiologic
mechanisms for effects against dependence exercised by
ayahuasca [45]. Neuroplasticity is first involved in the addiction
learning process, a maladaptive learning process that unfolds
in the acquisition of habits of drug dependence, the patterns
of learned behavior and association that contribute to the
compulsion and reward cycles involved in the habitual
self-administration of drugs.
Prickett and Liester [45] outline a variety of mechanisms are
involved in the production of neuroplasticity. These include the
elimination of synapses, formation of new synapses, a remodeling
of dendrites and axons). Ayahuasca can affect neuroplasticity
through a variety of neurochemical mechanisms that facilitate
changes in neural architecture, including the disruption of
learned associations that underlie addictive behaviors through
responses to triggers and cues that were hardwired into the
neural networks in the process of addiction. This ayahuasca
effect may facilitate neurophysiologic changes that address the
behavioral and neurochemical dynamics of addiction by causing
a neurological rewiring in the brain’s reward pathways.
Set and Setting: Context Effects in
Addressing Dependence
However the mere use of ayahuasca alone may not be
effective in reducing addictive behaviors; the importance of
the set and setting in psychedelic effects is a well-established
principal of the global mechanisms of action of these substances,
implicating social factors as significant variables in the reduction
of dependence. For example, the Takiwasi program [33]
attributes the treatments effects of ayahuasca as derived not
just from the physiological properties, but also from the ritual
conditions and the social environment, especially the interaction
of the patients’ personal psychology with the therapists and
other participants [33]. The program attributes a significant
therapeutic role to the content of the visionary experiences
that provides crucial information for the client, as well as the
psychological dispositions involving openness to the process and
a psychological surrender that manifests a commitment to the
ritual treatment processes. Fernández and Fábregas propose that
therapeutic efficacy of ayahuasca derives from, among other
factors, the visionary experiences of one’s past that provide
insights into the origins of the addictive patterns of behavior,
combined with other powerful emotional experiences, especially
death experiences and transpersonal experiences that lead to a
greater awareness of potential for personal transformation (also
see [34]).
The UDV members have commented on similar dynamics
as operating in the processes of remission of drug dependence,
especially as expressed in the concept of “recognition of one’s
errors.” This alludes to the dynamic effects of ayahuasca
in enhancing an awareness of one’s personal psychological
dynamics, connecting the patient with causal factors in their
personal past that contributed to dependency, and elevating
these repressed memories to consciousness. Acknowledgement
of these errors of the past and the path to better relations
with others reflect the pharmacological actions of ayahuasca
constituents. The ayahuasca visions and recollections of the
past are consequences of biological effects that contribute
important therapeutic dynamics through connecting the patient
with significant aspects of their personal past, elevating
repressed memories into consciousness where they can play
a role in psychological healing through restructuring. These
consciousness-enhancing effects of ayahuasca may be the
result of an increased activation of brain areas that enhance
somatic awareness, emotional arousal, emotional processing
(the right hemisphere areas of the anterior insula and
anterior cingulate/frontomedial cortex and left hemisphere
amygdala/parahippocampal gyrus structures) [55]. These brain
area activations elevate repressed memories into consciousness,
allowing for a novel reprocessing of these memories, particularly
those associated with a traumatic past relations with family
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Barbosa et al. Ayahuasca and Alcohol and Tobacco Use Disorder
members. Human imaging studies [54] led McKenna and Riba
[56] to postulated a model of ayahuasca effects involving
increased neuronal excitability in brain areas involved in sensory,
memory and emotional processing and inhibition of top-down
constraints or expectations. Those effects modulate ayahuasca-
induced visions, especially intense emotions and recollection of
personal memories; this allows for the safe exposure to emotional
events, similarly to cognitive and exposure therapies [54].
Evidence for such mechanisms of action involving ayahuasca are
suggested by studies of cognitive training interventions that have
shown promising results in reducing drug-related effects that are
mediated by memory and emotional neuromechanisms, such as
motivational salience of drug-associated stimuli, including the
context of alcohol and tobacco abuse (for review see [57]).
Broadly assessed, these studies suggest that religious and
psychological mechanisms, as well as pharmacological and
neurophysiological mechanisms, are involved in the reductions
in substance dependence among UDV members. Studies such as
the present one suggest that we can expect promising results in
reducing the effects of addictive drugs with the use of ayahuasca
is supportive settings. The regular group interaction of the
UDV members certainly constitutes a significant feature of the
social support for sobriety and social condemnation for lapses.
The twice monthly open religious meetings are supplemented
for members with several other opportunities for consumption
in settings for the advanced members in weekend retreat-like
settings, providing further involvement in life when drug-use
risks are higher.
Our finding that the history of consuming drugs is
significantly higher in UDV members than in Brazilian
population norms is noteworthy, as is their current status
with considerably lower levels of consumption. These findings
are recognized by the UDV members, who emphasize the
importance of their group as a drug-treatment strategy,
frequently citing the success of group membership in instilling
abstinence in certain members. It appears that members’
enthusiasm regarding the success of the group as a treatment for
substance dependence may also extend to a recruitment tool for
members of their social network who suffer such dependencies.
Such outreach may account for the relatively high rates of alcohol
and tobacco use reported by the members for the period prior to
their church adherence. Another possible contributory factor to
the high rates of prior dependence reported by UDV members
is their desire to emphasize the effectiveness of their religious
activity by overstating prior dependencies.
CONCLUSIONS
Although the molecular and cellular interactions of ayahuasca
are not yet fully established, a range of studies suggest that
ayahuasca has a broad range of psychoactive effects that
can modulate dependence in ways that reduce drug use and
abuse patterns. The present study provides further evidence
of those effects by showing that in a large population sample,
current levels of alcohol and tobacco dependence were lower
in ayahuasca users compared to the general population, even
though previous drug use was higher among this group prior
to becoming church members. Moreover, there was a substantial
negative relation of the variables assessing ceremonial ayahuasca
ingestion with the variables assessing substance use and
disorder, demonstrating that the attendance and consumption of
ayahuasca were likely the causal factors.
The cross-sectional design of the present study limits our
ability to establish a causal relationship between the ayahuasca
ceremonial attendance variables and lowering of substance use
and substance disorders in the UDV sample. Moreover, the
present design is vulnerable to self-selection and recall biases.
The major strength of the present study is the sample size of
ayahuasca users evaluated. Relative to the large scale survey
concluded recently [15], our study has the advantage of having
evaluated regular ayahuasca users, and of having analyzed the
association between different degrees of ceremonial ayahuasca
exposure with alcohol and tobacco use and disorder. Further
research to establish the physiological mechanisms involved in
reduction of substance abuse by ayahuasca should consider
separate use of extracted DMT and harmaline compounds in
double-blind assessments.
AUTHOR CONTRIBUTIONS
Each of the authors participated in this research by contributing
to the conception and design of the study PR, MW study
management, PR, MW, and LT collecting data, PR, MW, and
LT statistical analysis and interpretation PR, MW, LT, MB, RH,
LB, EM, and KA and the preparation of the manuscript PR, MW,
and LB.
FUNDING
The participation of MW in the study was funded in part by a
Fulbright Fellowship. Funding for this study was also provided
by grants to PR from the Conselho Nacional de Desenvolvimento
Científico e Tecnológico (CNPq) and by an internal grant from
Universidade Estadual de Santa Cruz.
ACKNOWLEDGMENTS
We wish to thank the Centro Espírita Beneficente União do
Vegetal (UDV), the UDV Scientific Committee (Comissão
Científica da UDV), the UDV Departamento Médico Científico
(DEMEC) and the UDV volunteers for supporting the study. We
also wish to thank Dr. Alberto Groisman for his initial support
for the study and Cleide Aparecida Moreira Silva from the
service of biostatistics from the Faculdade de Ciências Médicas da
Universidade Estadual de Campinas (UNICAMP) for the initial
management of dataset and analyses.
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Barbosa et al. Ayahuasca and Alcohol and Tobacco Use Disorder
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Conflict of Interest Statement: The authors declare that the research was
conducted in the absence of any commercial or financial relationships that could
be construed as a potential conflict of interest.
Copyright © 2018 Barbosa, Tófoli, Bogenschutz, Hoy, Berro, Marinho, Areco
and Winkelman. This is an open-access article distributed under the terms
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