Assessment of addiction severity among ritual users of ayahuasca

Ayahuasca is a psychoactive plant tea traditionally used in Amazonian indigenous medicine and magico-religious rituals. It is typically prepared from Banisteriopsis caapi, which provides reversible monoamine oxidase inhibitors (MAOIs), and Psychotria viridis, which contains the hallucinogen N,N-dimethyltryptamine (DMT). In recent decades Brazilian syncretic churches that employ ayahuasca in organised rituals have expanded internationally, prompting legal scrutiny because DMT is a controlled substance. Neurobiological distinctions between ayahuasca and classical drugs of abuse — notably predominant serotonergic actions of DMT versus the dopaminergic activation commonly implicated in addiction — plus ethnographic observations, raise questions about the beverage's abuse potential and its long-term psychosocial effects. Fábregas and colleagues designed two longitudinal, community-based comparative studies to assess addiction-related medical and psychosocial problems in regular ritual ayahuasca users. Using the Brazilian Portuguese version of the Addiction Severity Index (ASI) and a structured history of alcohol and illicit drug use, the investigators compared jungle-based and urban-based ayahuasca users with matched non-user control groups, with assessments at baseline and again about one year later. The primary objective was to determine whether continued ritual use of ayahuasca is associated with the types of deleterious outcomes typically seen with substances of abuse.

The paper reports two observational, longitudinal comparative studies conducted in Brazil. Study 1 sampled a jungle-based community of Santo Daime adherents from Céu do Mapià (Study 1 ayahuasca group) and matched non-users from the nearby town of Boca do Acre. Study 2 sampled urban members of an ayahuasca group called Barquinha in Río Branco (Study 2 ayahuasca group) and matched urban non-user controls. The principal inclusion criterion for ayahuasca groups was at least 15 years of ayahuasca consumption with a minimum frequency of twice per month. Reported ritual attendance averaged about six times per month in the jungle group and about eight times per month in the urban group. Controls were recruited to match age, sex and years of education; additional sociodemographic data (employment status, race, marital status, religion) were also recorded. Addiction-related outcomes were assessed using the 5th Edition Brazilian Portuguese Addiction Severity Index (ASI), a semi-structured interview that yields composite scores (range 0–1, higher = greater severity) for Medical Status, Employment/Support, Drug Use, Alcohol Use, Legal Status, Family/Social Relationships and Psychiatric Status. The ASI was administered at baseline and again after approximately 8–12 months. Lifetime and past-month use of alcohol and nine categories of psychotropic drugs were recorded separately; the extracted text notes that the Drug Use subscale scoring included ayahuasca itself. For statistical analysis, categorical sociodemographic and substance-use variables were compared between groups with chi-squared tests, and continuous variables (age, education, income) with unpaired Student's t-tests. Group differences on ASI subscales at baseline and follow-up were tested with unpaired t-tests. Time-dependent changes were examined with repeated-measures analyses of variance (ANOVAs) using timepoint (pre vs post) as a within-subjects factor and study (Study 1 vs Study 2) and group (ayahuasca users vs controls) as between-subjects factors; interactions of interest included group by timepoint and study by group by timepoint. The authors report use of SPSS 17.0. The longitudinal design produced participant attrition between assessments and actual follow-up sample sizes are reported in the Results section. Some detailed results on prior drug use are presented in supplementary online material.

Study 1 (jungle-based community): At baseline 56 regular ayahuasca users and 56 matched non-users were assessed. No significant differences were found between groups in sex, age, years of education or income, although controls had higher employment qualification by Hollingshead categories; ethnic composition and marital status differed between groups. At 1-year follow-up 39 ayahuasca users and 49 controls were reassessed. On ASI subscales at baseline, the ayahuasca group scored significantly lower than controls on Medical Status, Alcohol Use and Psychiatric Status, and scored significantly higher on the Drug Use subscale. There were no baseline group differences on Employment/Support or Family/Social Relationships, and both groups scored 0 on Legal Status. At follow-up, the ayahuasca group remained significantly lower than controls on Alcohol Use and Psychiatric Status, and remained higher on Drug Use. History data indicated the jungle ayahuasca group had a significantly higher frequency of prior illicit drug use in several categories, but most prior use had ceased by the time of assessment except for cannabis; more detailed breakdowns are provided in the supplementary material. Study 2 (urban context): Baseline assessment included 71 urban ayahuasca users and 59 controls; follow-up comprised 39 users and 19 controls. No significant demographic differences were observed between groups. At baseline the ayahuasca group scored significantly lower than controls on Alcohol Use, Family/Social Relationships and Psychiatric Status, and scored significantly higher on Employment/Support and Drug Use subscales. At 1 year the ayahuasca group scored significantly lower on Medical Status and significantly higher on Drug Use compared with controls. Prior alcohol and illicit drug histories showed no statistically significant differences between groups in Study 2 according to the extracted text; supplementary materials reportedly include further detail. Combined time-dependent analyses: When both studies were analysed together in repeated-measures ANOVAs, two significant study by group by timepoint interactions emerged. For the Drug Use subscale there was a significant interaction [F(1,142) = 4.9, p = 0.028], reflecting a larger decrease (improvement) over time in the ayahuasca group than in controls, but this effect was restricted to Study 1. For the Family/Social Relationships subscale the interaction was also significant [F(1,142) = 5.4, p = 0.022], reflecting a larger increase (worsening) over time in the ayahuasca group than in controls, but this was restricted to Study 2. All other interactions across the seven ASI subscales were non-significant. The authors note that ASI scores in these samples were generally lower than those reported for several Brazilian and international groups of drug users, and that the Drug Use subscale scores were influenced by inclusion of ayahuasca (and cannabis in the Mapiá group).

Fábregas and colleagues interpret their findings as showing that ritual ayahuasca users do not exhibit the pattern of deleterious psychosocial consequences typically associated with other drugs of abuse when assessed with the ASI. Both ayahuasca-using groups scored significantly lower than their respective controls on Alcohol Use and Psychiatric Status at baseline, and these differences persisted at 1 year in the jungle-based group but not in the urban group. Only one subscale showed a time-dependent worsening despite ongoing ayahuasca use: Family/Social Relationships in the urban study. The investigators suggest this worsening may relate to involvement with the urban church rather than to ayahuasca consumption per se, given that the effect was observed in the urban sample but not in the more isolated jungle community. The authors note that higher Drug Use subscale scores among ayahuasca users largely reflect inclusion of ayahuasca itself in the scoring and, in the jungle cohort, concurrent cannabis use. They point out that prior use of other illicit drugs reported in the jungle group had largely ceased by the time of assessment, and that neither group recorded problems on the Legal Status subscale. Taken together with prior studies that failed to find neuropsychiatric disorders or cognitive deficits in long-term ritual users, these observations lead the investigators to conclude that ayahuasca appears to have low abuse potential in these settings. Limitations acknowledged or implicit in the report include participant attrition between baseline and follow-up and reliance on the ASI as the primary instrument; detailed histories and some results are reported only in supplementary material. The authors recommend further research to determine whether the apparently low association with addiction-related psychosocial harm is attributable to the pharmacological properties of ayahuasca itself or to the sociocultural and ritual context in which it is consumed.