This open-label study (n=36) found that ayahuasca led to significant (and clinically relevant) changes in addiction scores (e.g. ASI) and cognitive function. There was significant drop-out (39%), and the open-label character makes it difficult to draw causative conclusion. Still, this research provides another data point for ayahuasca for substance use disorder (SUD) treatment.
Aims
The therapeutic use of psychedelics is regaining scientific momentum, but similarly psychoactive ethnobotanical substances have a long history of medical (and other) uses in indigenous contexts. Here we aimed to evaluate patient outcomes in a residential addiction treatment center that employs a novel combination of Western and traditional Amazonian methods.
Methods
The study was observational, with repeated measures applied throughout treatment. All tests were administered in the center, which is located in Tarapoto, Peru. Data were collected between 2014 and 2015, and the study sample consisted of 36 male inpatients who were motivated to seek treatment and who entered into treatment voluntarily. Around 58% of the sample was from South America, 28% from Europe, and the remaining 14% from North America. We primarily employed repeated measures on a psychological test battery administered throughout treatment, measuring perceived stress, craving frequency, mental illness symptoms, spiritual well-being, and physical and emotional health. Addiction severity was measured on intake, and neuropsychological performance was assessed in a subsample from intake to at least 2 months into treatment.
Results
Statistically significant and clinically positive changes were found across all repeated measures. These changes appeared early in the treatment and were maintained over time. Significant improvements were also found for neuropsychological functioning.
Conclusion
These results provide evidence for treatment safety in a highly novel addiction treatment setting, while also suggesting positive therapeutic effects.
Papers cited by this study that are also in Blossom
Fuentes, J. J., Fonseca, F., Elices, M. et al. · Frontiers in Psychiatry (2020)
Mangini, M. · Journal of Psychoactive Drugs (2011)
Carhart-Harris, R. L., Goodwin, G. M. · Neuropsychopharmacology (2017)
Chi, T., Gold, J. A. · Journal of the Neurological Sciences (2020)
Berlowitz and colleagues situate their work within a renewed scientific interest in psychedelics and note that ethnobotanical psychoactive substances have long been used in indigenous medical contexts. The introduction outlines ayahuasca (the DMT-containing decoction prepared from Banisteriopsis caapi plus DMT-containing leaves) as an example of a traditionally used medicine with growing evidence for therapeutic potential in conditions including substance use disorders, depression and anxiety. The authors describe the Takiwasi Center in Peru, a nationally accredited residential programme that has combined ayahuasca and other Amazonian plant-based techniques (including dietary retreats and emetic preparations) with Western biomedical and psychotherapeutic approaches since 1992, but they note scientific characterisation of outcomes at the centre has been limited. This study aims to address gaps in the earlier observational evaluations of Takiwasi by examining within-treatment change with higher temporal resolution. Rather than isolating single treatment components, the researchers adopt an observational "black box" approach, using repeated psychological and neuropsychological measurements across defined treatment milestones to characterise the timing and magnitude of patient changes during the residential programme.
The study was an observational repeated-measures cohort conducted at the Takiwasi residential centre in Tarapoto, Peru. Ethical approval was obtained and all participants gave written informed consent. Participation was open to patients admitted to Takiwasi for addiction treatment during April 2014 to August 2015; no patients declined participation and study participation ceased when a patient left treatment. The final analytic sample comprised 36 male inpatients (ages 20–50, mean 29, SD 7). The sample was international (58% South American, 28% European, 14% North American). Commonly reported substances prior to admission were alcohol (83%), cannabis (71%) and cocaine (51%), with 66% reporting poly-drug use. Treatment completion outcomes were reported: 61% completed treatment, 22% exited voluntarily against staff recommendation, 14% were suspended, and 3% abandoned without advising staff. Takiwasi's treatment protocol is a multi-stage, largely inpatient programme typically lasting around 9 months (flexible), comprising initial isolation (about 8–10 days), main treatment (around 7 months) and a reinsertion phase (~2 months). The programme integrates physical detoxification (including emetic and psychoactive plants), group and individual psychotherapy, occupational therapy and community living, spiritual and psychological development through psychoactive plant sessions and dietary retreats, and biomedical evaluation. The centre excludes individuals with a history of psychosis and certain serious medical conditions; psychiatric medications are ceased prior to entry where interactions are possible. Measures included the Addiction Severity Index (ASI) administered at intake, and a clinical battery repeated at treatment milestones: Perceived Stress Scale (PSS-10), Craving Experience Questionnaire—frequency (CEQ-F), Brief Symptom Inventory Global Severity Index (BSI GSI), Spiritual Well-Being Scale (SWBS; Religious and Existential subscales), SF-36v2 Physical and Mental Component Summaries (PCS and MCS), and a single Self-Evaluated Transition (SET) item from SF-36v2. Neuropsychological functioning was assessed with the RBANS in a Spanish-speaking subsample (n = 8) at intake and at a follow-up at least 2 months into treatment. Clinical battery milestones (M1–M5) corresponded to admission, approximately 1 month after each diet, and exit. Sample sizes at M1–M5 were 22, 19, 18, 13 and 9 respectively; average days in treatment at these milestones were 3, 110, 169, 245 and 309 days. Analyses were performed in R. Intake ASI and some clinical battery scores were compared with available normative samples using one-sample t-tests. Within-treatment change on the clinical battery was modelled with mixed-effects models (fixed effect: treatment milestone as a categorical predictor; random effect: patient intercept only) to make use of all available repeated measures and account for within-subject dependence. Addition of total treatment time (days) was tested but not retained based on AIC. Paired-samples t-tests (Hedges' corrected effect sizes) compared RBANS intake and follow-up scores. A logistic regression examined predictors of early dropout (defined as <30 days in treatment) using demographics and ASI intake scores.
Intake profile: On intake the Takiwasi sample showed a high severity of addiction. ASI composite comparisons with available normative inpatient samples indicated elevations in drug-related and family problem domains relative to mainstream centres; the extracted text does not clearly report all specific t-statistics for every ASI domain. ASI psychiatric cutoff comparisons and elevated intake BSI GSI scores suggested psychiatric comorbidity was common. Medical problems were, on average, less severe than a Canadian readmission sample and comparable to US inpatient averages. On the intake clinical battery (n = 22 for most measures, n = 27 for CEQ-F), perceived stress and craving frequency were high, and mental and emotional health were low. Religious well-being (RWB) was possibly lower than US mental health patients (t(21) = -2.21, p = 0.038, d = -0.47, 95% CI for d (-1.37, 0.43)). Existential well‑being (EWB) was not different from US mental health patients (t(21) = -0.41, p = 0.686). CEQ-F scores were significantly higher than an Australian alcohol outpatient sample (t(26) = 4.01, p < 0.001, d = 0.77, 95% CI (-0.05, 1.59)). Cognitive functioning at intake was described as around the "low average" range. Within-treatment changes: Mixed-effects models comparing each milestone against M1 showed statistically significant and clinically positive changes across the repeated measures. For measures where higher scores indicate worse outcomes (for example perceived stress, GSI, craving), model estimates were significant (all p < 0.001 except GSI at M3 where p < 0.01), indicating reductions over time. For measures where higher scores indicate better outcomes (for example SF-36 MCS, SWBS EWB), estimates indicated improvements. The authors report particularly strong increases in mental and emotional health and existential well-being, and large reductions in perceived stress, psychiatric symptoms and craving. The most pronounced changes occurred early in treatment and were generally maintained thereafter, though later-stage analyses had limited statistical power. The SET single-item ratings (n = 22 at M1; n = 28 across M2–M5 with 59 administrations) showed that after intake no patients in treatment rated their health as "somewhat worse" or "much worse," and only two rated it "about the same," with the rest indicating improvement. Neuropsychological functioning: In the RBANS subsample (n = 8), mean scores increased across all indexes from intake to follow-up. Paired t-tests found significant improvement for the Total Scale (t(7) = 3.37, p = 0.012, Hedges' g = 0.55, 95% CI for g (0.17, 0.92)) and for Delayed Memory (t(7) = 2.73, p = 0.029, g = 0.74, CI (0.08, 1.40)). Other index comparisons are reported in the paper's tables but were not all statistically significant. Dropout analysis: Early treatment dropouts (n = 6; defined as <30 days in treatment) did not differ from the rest of the sample (n = 30) in nationality, religion or ASI intake scores according to logistic regression. However, age was a significant difference: early dropouts were younger (mean 22 years, SD 2) than the rest (mean 30 years, SD 7), t(26) = -5.24, p < 0.001, Cohen's d = -1.24, 95% CI for d (-2.17, -0.30).
Berlowitz and colleagues interpret their findings as indicating that patients admitted to Takiwasi present with relatively severe addiction profiles and psychiatric comorbidity, yet tend to show clinically meaningful improvements across multiple domains during residential treatment. The authors emphasise that improvements—large reductions in perceived stress, psychiatric symptoms and craving, increases in mental and emotional health and in existential well‑being—appeared relatively early in the treatment course and were generally maintained thereafter. Neuropsychological data provided additional evidence for improvement, notably in delayed memory. The authors situate their results alongside prior observational reports from Takiwasi and the wider literature on indigenous psychoactive plant sacraments and classical hallucinogens, noting consistency with earlier findings of posttreatment improvements. They highlight a divergence between existential and religious dimensions of spiritual well‑being: existential well‑being showed stronger predicted increases, whereas religious well‑being was more variable, a pattern the authors suggest may reflect baseline differences in religiosity and differing patient responses to spiritual content in plant ceremonies. The authors explicitly acknowledge limitations arising from the observational, "black box" design, which precludes causal attribution to specific treatment components. They note other plausible contributors to observed change including enforced abstinence, removal from daily life, development of community within the centre, and the passage of time. They also discuss safety considerations: while ayahuasca has an acceptable pharmacological safety profile, many Amazonian techniques used at Takiwasi remain scientifically understudied; the centre's exclusion criteria, biomedical evaluations and practitioner expertise likely increase safety, particularly for international patients where drug–medicine interactions might be more likely. The authors caution that the admission protocol selects for motivated patients, which limits generalisability, and that follow-up studies are required to determine whether within-treatment changes translate into longer-term recovery in community settings. As implications, the authors call for further clinical research to assess effectiveness and longitudinal outcomes, and for qualitative work to provide converging evidence on mechanisms, the nature of treatment components (for example the role of dietary retreats versus ayahuasca ceremonies), and concepts of health and safety in this treatment context. They also note the potential relevance of gut–brain axis mechanisms given the focus on emetic and plant-based treatments.
The authors conclude that Takiwasi represents a distinctive, long-standing example of a treatment approach that integrates traditional Amazonian medicine with Western clinical practice, and that the observed within-treatment improvements are consistent with growing evidence for therapeutic effects of indigenous psychoactive plant sacraments and classical hallucinogens. They stress that further clinical trials, longitudinal follow-up and qualitative studies are needed to evaluate treatment effectiveness, delineate mechanisms, and clarify safety and appropriateness for different patient populations.
Addiction treatment was an exciting line of inquiry during the first wave of psychedelic research in the mid-20th century, but the field was marred by inadequate research methodology and growing controversies that led to a near total investigatory suspension.After a decades-long hiatus, a revitalized second wave is now well underway.Once again, addictions are a target of psychedelic research with some impressive early results,and there is hope for a breakthrough treatment similar to the recent success of MDMA-assisted psychotherapy for post-traumatic stress disorder.Yet while the psychiatric discovery and embrace of psychedelics is relatively recent, the use of similar substances in shamanic and ethnomedical contexts is much older and is likely to have ancient roots.Therapeutic use of ayahuasca One such ethnobotanical substance is ayahuascathe common name of the vine Banisteriopsis caapi, which contains monoamine oxidase-inhibiting β-carbolines and is traditionally used alone or with various admixtures-but also the name of the decoction prepared from B. caapi and the leaves of a plant containing the psychedelic N,N-DMT,such as Psychotria viridis or Diplopterys cabrerana.Ayahuasca (i.e. the DMT-containing decoction) is powerfully psychoactive but appears to be safe when used appropriately.In recent times its therapeutic potential has been increasingly documented, particularly for the alleviation of substance abuse, depression, and anxiety-related disorders.Ayahuasca is not considered to carry a high intrinsic addiction potential,and indeed suggestions of anti-addictive outcomes have been reported since the earliest biomedical study on the sacramental use of ayahuasca,with evidence slowly accumulating since then.Various potential mechanisms have been proposed,yet quantitative studies of ayahuasca for addiction have only rarely been conducted in explicitly therapeutic settings,in part due to regulatory challenges.The Takiwasi Center Running parallel to these developments is a wellestablished and nationally accredited therapeutic community in Peru, the Takiwasi Center, which has been employing ayahuasca in the treatment of addictions since 1992-around the same time that human psychedelic research resumed.However, Takiwasi is rather poorly characterized as an "ayahuasca-assisted" treatment, since a variety of other traditional techniques are used; for example, the traditional dieta (diet) is particularly important, during which a patient enters social seclusion while receiving restricted alimentation, along with the intake of prescribed medicinal plants.The ceremonial use of ayahuasca, diets, and other plant-based techniques proceed from traditional Amazonian medicine,which Takiwasi combine with Western psychotherapeutic and biomedical approaches. Being founded by a French medical doctor, the combination of Amazonian and Western medicine in Takiwasi is operated from within a biopsychosocial-spiritual framework.For example, clinical staff at the center may be healers with training in traditional Amazonian medicine, but there are also professional doctors, psychologists, and nurses. Due to potential interactions between pharmaceuticals and plant medicines,patients cease taking psychiatric medications prior to entry, although this does not apply to those with a history of psychosis, as they would not be accepted for treatment.Certain physical health conditions are also part of the center's exclusion criteria, including diabetes, gastric ulcers, and epilepsy, but also renal, cardiac, respiratory or hepatic insufficiency.Once admitted, the ideal treatment process lasts around 9 months (although this is flexible), and progresses through stages of: (a) initial isolation (around 8-10 days); (b) main treatment (around 7 months); and finally (c) a reinsertion phase (around 2 months) where patients continue with the main treatment, but are preparing for post-treatment life and thus are able to leave the center and engage in work in the community (see Figure). Across the phases, treatment primarily revolves around physical detoxification (focusing on the use of emetic and psychoactive plant preparations), psychotherapy (group and individual), occupational therapy, community living, psychological and spiritual development (through psychoactive plant sessions and diets), and also biomedical evaluation. The application of medicinal plants in Takiwasi has parallels to psychedelic-assisted psychotherapy, although the Takiwasi framework differs in that its roots are in traditional Amazonian medicine. More detailed descriptions of these treatment procedures have been provided by Berlowitz et al.,Mabit et al.,Bustos,and O'Shaughnessy.
Takiwasi offers the potential for generating unique insights into the use of traditional medicines in addiction treatment, including, but not limited to the use of ayahuasca. Yet while the center's own publications have reported positive patient outcomes,scientific evaluation has been lacking.It is of significance then that results from the first preliminary observational study of Takiwasi's treatment have recently been published,with analyses showing improvements for treatment completers in terms of addiction severity, craving, emotional distress, and quality of life. Comparable results were recently reported in a second observational study,which showed posttreatment improvements in anxiety and depression scores, as well as improved scores on quality of life and spirituality. Although the effect sizes in these studies were large, the end-point analyses used in both studies opened questions about the timing of within-treatment changes, particularly with regard to treatment dropouts that were excluded from analysis. Here we build on these results by reporting on patient changes at multiple points within treatment. Given the clinically and theoretically complex nature of addictions,we attempted to characterize within-treatment change as broadly as possible by following the multi-dimensional addiction recovery model proposed by Dodge et al.
The study was approved by the James Cook University Human Research Ethics Committee (H5267), and all participants gave written informed consent prior to participation. We used the STROBE cohort checklist when writing this report.Participants Participation in the study was open to all patients who were: (a) seeking treatment for addiction, and (b) had passed Takiwasi's admission protocol and been admitted as inpatients. Although we did not measure treatment motivation, all patients entered into treatment voluntarily, and previous studies suggest that the majority of Takiwasi patients arrive motivated to seek change.No patients declined to participate in the study. Data were collected from April 2014 to August 2015, and while not all patients completed the full course of treatment, no patients dropped out of the study while in treatment (although study participation ended once a patient had left treatment). As only male inpatients are admitted to Takiwasi, the final sample consisted of 36 male inpatients with ages on treatment admission ranging from 20 to 50 years (M = 29, SD = 7), and total time in treatment (from entry to exit) ranging from 3 to 367 days (M = 183, SD = 118). South Americans made up 58% of the sample, with 28% European, and the remaining 14% North American. Prior to treatment, the most commonly consumed drugs were alcohol (83%), cannabis (71%), and cocaine (51%), with poly-drug use being common (66%). Of the sample, 61% completed the treatment, 22% exited voluntarily (i.e. against staff recommendation), 14% were suspended from treatment, and one patient (3%) abandoned the treatment without advising staff. Further demographics can be found in Table.
Similar to Berlowitz et al.and in accordance with World Health Organization recommendations for the evaluation of traditional medicines,the overall study design consisted of an observational "black box" view of patient change throughout treatment, which was not intended to isolate specific aspects of the treatment for analysis. We therefore obtained repeated measures on psychological variables in order to assess clinical change in a global sense.
Addiction severity. The fifth edition of the Addiction Severity Index (ASI)is a widely used structured clinical interview that attempts to quantify a patient's addiction severity across seven life problem areas: medical, alcohol, drug, employment, legal, family, and psychiatric. Higher scores indicate greater problem severity for each dimension. Clinical battery. The clinical battery tests were selected for their relevance in the addiction literature, but also for the suitability of individual test items within a residential treatment context. The measures used were as follows. Perceived Stress Scale (PSS). The PSSwas used to measure psychological stress over the previous month. Analyses were made on the 10-item subset (PSS-10), due to its improved psychometric properties.Higher scores indicate greater perceived stress. Craving Experience Questionnaire-frequency (CEQ-F). The CEQ-F 82 was used to measure the frequency of craving experienced over the past 30 days. Craving is conceptualized in terms of frequency of desire, craving-related imagery, and intrusive thoughts. Higher scores indicate greater frequency of craving over the month prior.
The BSIwas used to assess the prevalence of psychiatric disorder symptoms over the previous 7 days. The test is a shorter 53-item version of the Symptom Checklist-90 Revised,and both instruments measure psychiatric symptoms across nine dimensions. Only results for the Global Severity Index (GSI) are reported here, where higher scores indicate greater overall problem severity.
The SWBSwas used to assess two dimensions at the time of testing: Religious Well-Being (RWB) and Existential Well-Being (EWB). RWB items explicitly address religious and spiritual notions of God, whereas EWB items are secular and probe life satisfaction and meaning. On both dimensions, higher scores indicate greater well-being.
). The SF-36v2was used to capture perceived changes in health over the past 4 weeks. While the SF-36v2 measures eight health domains, we only report here the global measures of: (a) physical health (Physical Component Summary; PCS), and (b) mental/emotional health (Mental Component Summary; MCS). For both domains, higher scores indicate better health.
The SET is a single 5-choice item from the SF-36v2 that captures perceived change in general health over the past year. The patient rates their current "health in general" compared with 1 year prior as either: 1 (much better), 2 (somewhat better), 3 (about the same), 4 (somewhat worse), or 5 (much worse). Neuropsychological functioning. The Repeated Battery for the Assessment of Neuropsychological Functioning Update (RBANS)was used to test for abnormal cognitive functioning. With two equivalent testing forms, the Spanish version allows for a single retest only. The instrument assesses performance through 12 subtests that comprise five indexes: immediate memory, visuospatial, language, attention, and delayed memory. For all indexes, higher scores indicate better performance (with low scores relative to age bracketed norms suggesting cognitive impairment).
Addiction severity. The ASI was administered to patients on intake only, most often by a co-author of this work (I.B.), but at times by Takiwasi staff instead. It was administered on average 2 days into treatment (SD = 3 days). Clinical battery. Measurements on the clinical battery were made at important treatment points that we termed milestones. In consultation with Takiwasi staff, the selected milestones were: (a) treatment admission, (b) approximately 1 month after each diet, and (c) exit from treatment (although it should be noted that in practice treatment exit could occur at any point for a variety of reasons). There were five milestones in total, herein designated M 1 -M 5 . Dieting provided a natural measurement point in treatment, since it occurs with some regularity (around every 2-3 months) and marks a consolidation point for patients within the treatment. Moreover, the diets are followed by a reflective phase where patient plant intake is negligible, which allowed us to minimize interference from the acute effects of psychoactive plants when taking repeated measures. From M 1 to M 5 , the sample sizes were 22, 19, 18, 13, and 9, respectively (N = 36). The average number of days in treatment (with standard deviations) for patients at M 1 -M 5 were: 3 (3), 110 (31), 169 (31), 245 (30), and 309 (27). Neuropsychological functioning. The RBANS was administered on treatment intake, and at a follow-up point either at the end of treatment, or at least 2 months into treatment (n = 8). The average number of days in treatment before the second administration was 153 (SD = 70). Given the language-dependent nature of some test sections, the RBANS was only administered to fluent Spanish speakers. Analyses. All analyses were conducted using R.Effect sizes for t-tests were calculated with effsize.Mixed-effects models were generated using lme4,with significance values from lmerTest using Satterthwaite's method.Intake comparisons. For group analysis we compared the sample's intake ASI scores with normative values from mainstream inpatient centers. Due to the cultural diversity of Takiwasi's patients and the lack of global ASI normative data, these comparisons were unavoidably cross-cultural. One-sample t-tests were used to check for significant differences. We also compared Takiwasi patients' intake scores (M 1 ) on the clinical battery against available normative samples using onesample t-tests. Within-treatment changes. We analyzed the clinical battery in terms of predicted change over time from M 1 versus M 2 -M 5 (plotted against normative values for comparative purposes). Mixedeffects models were used to maximize the data available for analysis (i.e. we included all data points in the analyses, irrespective of a patient's time in treatment at study enrollment, or reason for treatment exit), and also to account for the lack of statistical independence due to repeated measures.In all models the fixed effect was treatment milestone (categorical), with patient as the random effect. All models were random intercept only, and thus implied the modeling assumption of an invariant effect of time spent in treatment across patients. Since treatment milestone was a proxy for time spent in treatment, we also tested the models with the addition of total treatment time (in days) as a predictor, but its addition was not warranted based on Akaike information criterion (AIC) values. For neuropsychological functioning, we compared intake and within-treatment performance using paired-samples t-tests, using Hedges'correction for Cohen's d as the effect size. Dropout analysis. We compared early treatment dropouts (i.e. those who spent less than 30 days in treatment) against the rest of the sample via a logistic regression, using demographics and ASI intake scores as predictors, and a binary "dropout" variable as the outcome.
We first characterize the Takiwasi sample on intake, making comparisons against available normative values. Addiction severity. Figureshows ASI composite score means and standard errors for the Takiwasi sample (n = 34; ASI data were unavailable for two patients), Canadian addiction patients being readmitted to treatment with at least three previous attempts (sample sizes range from 517 to 1474),and USA addiction inpatients (N = 3133).Compared with the Canadian sample, Takiwasi patients had significantly higher scores on (a) drug, t(Clinical battery. For the intake sample (n = 22; except for CEQ, n = 27), we first made comparisons where non-clinical norms were available. We found that (a) PCS scores were not significantly different from the US average (N = 4024): t(For those measures where only clinical comparisons were available, we found that (a) RWB scores were possibly lower than US mental health patients (N = 182): t(21) = -2.21, p = 0.038, d = -0.47, 95% CI for d (-1.37, 0.43); (b) EWB scores were not significantly different from US mental health patients (N = 182): t(21) = -0.41, p = 0.686, d = -0.09, CI (-0.97, 0.80); and (c) CEQ-F scores were significantly higher than an Australian sample of alcohol abuse outpatients (N = 276): t(26) = 4.01, p < 0.001, d = 0.77, CI (-0.05, 1.59).
Here we present predictive mixed-effects models for patient change throughout treatment on the clinical battery, where each estimate is relative to M 1 , plotted alongside norms from the sources previously mentioned in the intake analyses. FigureFigureshows model estimates for those tests where higher scores indicate negative clinical outcomes. All estimates are significant at p < 0.001, except for GSI M 3 (p < 0.01). Estimate confidence intervals for both positive and negatively grouped tests can be found in Tablesand. Self-evaluated transition. Figureshows response percentages for the SET item, comparing health transition on intake (M 1 ; n = 22) versus repeated measures during treatment (M 2 -M 5 ; n = 28, with 59 administrations total). Excluding intake, no patients in treatment ever rated their health as "somewhat worse" or "much worse," and there were only two that ever rated their health as "about the same." Neuropsychological functioning. Mean score increases from intake to treatment for the group (n = 8) were found for all indexes. However, paired-samples t-tests for treatment versus intake scores were only significant for Total Scale, t(7) = 3.37, p = 0.012, g = 0.55, 95% CI for g (0.17, 0.92); and Delayed Memory, t(7) = 2.73, p = 0.029, g = 0.74, CI (0.08, 1.40). Complete index comparisons can be found in Table.
Logistic regression analyses showed no significant relationships between early treatment dropouts (i.e. those who spent less than 30 days in treatment; n = 6) and the rest of the sample (n = 30) for either nationality, religion, or ASI intake scores (for all dimensions). However, patient age at treatment admission was significant, and for simplicity we report t-test results for age between the two samples: Early treatment dropouts were younger (M = 22 years, SD = 2) than the rest of the sample (M = 30 years, SD = 7), t(26) = -5.24, p < 0.001, Cohen's d = -1.24, 95% CI for d (-2.17, -0.30).
Our results indicate that Takiwasi patients can be expected to have a high severity of addiction on intake, with ASI elevations at least on drug and family problems in comparison to mainstream centers. Based on ASI psychiatric cutoff scores,Takiwasi patients are also likely to have psychiatric co-morbidity on admission, a finding supported by intake GSI elevations, and also recent results from Berlowitz et al.where affective and anxiety disorders were found to be prevalent. Overall, the Takiwasi patients' addiction severity profile was comparable to the most severe Canadian readmission sample reported by Simoneau and Brochu,where patients with higher problem severity were re-seeking treatment after at least three prior admissions. However, medical problems in the Takiwasi sample were less severe than the Canadian sample, being more comparable in that domain to the US inpatient average. The intake profile on the clinical battery supported the ASI findings, and portrayed patients that are likely to be highly stressed, suffering from mental illness symptoms, and experiencing frequent craving. Mental and emotional health is likely to be especially low, although we did not find evidence that physical health is low on average. Religious
and existential well-being were comparable to US clinical populations, and cognitive functioning may be in the "low average" range.
Over the course of treatment, we find that Takiwasi patients are likely to make clinically significant improvements on a variety of measures relevant to addiction. Specifically, patients are predicted to see strong increases in mental and emotional health, in addition to increased meaning and purpose in life. Large reductions in perceived stress, mental illness symptoms, and craving can also be expected. The most dramatic shifts appeared earlier in the treatment, and these changes seem to be at least maintained over time (if not further improved), although we had limited statistical power to assess later stage changes. Although Berlowitz et al.found that Takiwasi treatment completers had large and clinically significant improvements on nearly all measures, no significant changes in physical health were found. However, as the authors note, ASI medical composite scores may not be sufficiently sensitive for this purpose. Our application of the SF-36v2 supported this interpretation, as the physical health models suggested a general improvement in health that was maintained over the course of treatment. Additionally, self-reported health transitions were nearly universally positive for all measurement points beyond intake. Cognitive functioning provided further evidence for improvement, which was most notable in the domain of delayed memory.While our results accord with the end-point analyses of Berlowitz et al.and Giovannetti et al.,here we increased the temporal resolution of within-treatment measurement, finding that clinical improvements occur relatively quickly (compared with the length of the full treatment), suggesting that dropouts roughly beyond the third month are unlikely to be caused by lack of clinical change. However, our results did suggest that younger patients may be more likely to drop out of treatment early on. Further investigations of patient change within the opening months of treatment appear to be warranted. Finally, we found some divergence in the modeling of spiritual well-being throughout treatment. Takiwasi's treatment regime is complex, and spirituality and religion play multifaceted roles within it. Psychedelics are known to induce altered states of consciousness of a "mystical" type 101-103 with potentially profound implications, 104,105 and ayahuasca can be similarly potent.It is interesting then to note the differences that we observed for Takiwasi patients, with strong predicted increases in existential well-being (perhaps even toward levels seen in US religious samples), whereas spiritual well-being formulated in explicitly religious terms was more uncertain. This contrast possibly reflects pre-existing differences in religiosity (e.g. 50% of the sample were non-religious on admission), but also suggests differences for patients in coming to terms with the apparent spiritual content of ayahuasca and other plant ceremonies. 108
Our observational study design precludes the causal attribution of patient change to particular aspects of the treatment, although the use of ayahuasca gives an obvious and empirically supported target for treatment effects.Importantly however, the design does not distinguish between specific treatment interventions and the unusual environment of a residential center: Other variables such as the passage of time, the potential development of community and friendships within treatment, the lack of access to drugs of abuse, and the removal of patients from their daily life circumstances would all be probable contributing factors to changes seen within treatment. On the other hand, it is worth noting that many of the treatment processes are demanding (e.g. many of the plants utilized in Takiwasi induce emesis), and they are unlikely to be considered at all pleasant by patients. In this sense it is impressive that patients with serious addiction problems continue with the treatment for as long as they often do. Despite the above limitations, the uniformity of the present results would be surprising if the effects of the treatment were broadly deleterious. Thus at a minimum, we provide evidence of treatment safety in a highly novel setting. However, while ayahuasca is known to have an acceptable safety profile from a pharmacological perspective,many of the Amazonian techniques used in Takiwasi are not yet well studied scientifically, despite indigenous and community usage of the same plants in medical and other contexts.Thus although Takiwasi's exclusion criteria,biomedical evaluation, and practitioner expertise likely increase the safety margin-particularly for international and urban patients where interactions not seen in traditional settings increase in likelihood (e.g. pharmaceutical interactions)-further study is needed on the basic effects of Amazonian medicinal plants and practices. Our results also strongly suggest a therapeutic effect, but we cannot yet determine if these patient changes translate into addiction treatment success. Linking our findings to treatment effectiveness would require longitudinal studies that follow-up on patients once they return to their communities, where there are likely to be more opportunities for relapse. Moreover, it is difficult to assess how well these results would generalize to other patients seeking treatment, given that the Takiwasi admission protocol filters out those who are not yet motivated to commit to treatment,implying that the treatment may be suited to certain patient profiles.Yet irrespective of the admission protocol, it seems unlikely that patients who are not ready to change would stand to benefit from this approach, especially considering the difficult nature of the treatment. However, given the cultural diversity and relatively severe addiction profile of the sample, our results do suggest that this mode of treatment may hold promise in those areas where conventional treatment approaches are failing. Overall, our findings are consistent with the contemporary literature on the use of indigenous psychoactive plant sacraments,and the use of classical hallucinogens more generally.However, the present results should not be associated with the use of ayahuasca alone, especially considering that it forms one element in a complicated treatment protocol (see Figure). For example, when asked to select the most important aspects of the treatment, Takiwasi healers in fact most frequently chose dietary retreats, even though ayahuasca ceremonies were also considered to be important.Moreover, the focus on medicinal plants and emesis may be connected to effects in the gut-brain axis,which has recently been linked with opioid dependence.
The resurgence of psychedelic research holds promise for the addiction treatment field, and Takiwasi provides a unique parallel to these developments, by now carrying decades of clinical experience. Takiwasi's treatment protocol is more deeply connected with traditional medical practices, and while such an approach may have its own benefits and be more (or less) appropriate for specific populations, further clinical work is called for in order to investigate treatment effectiveness. Qualitative work may also be helpful not only in providing converging lines of evidence for treatment effects and potential mechanisms, but for further delineating the nature of the treatment itself, particularly in relation to concepts of health, illness, and safety, and how they relate to the reemerging field of psychedelic medicine.
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