Symptom specificity of ayahuasca's effect on depressive symptoms

Major Depressive Disorder is common, costly and frequently recurrent, and available pharmacological and psychological treatments leave a substantial minority of people unimproved. The introduction summarises drawbacks of standard care: antidepressant medications can cause adverse effects and withdrawal, psychotherapy can be time-consuming and inaccessible, and both approaches often take weeks to produce relief. The authors note that different treatments can alter particular symptoms unevenly and that clients often prioritise certain symptoms (for example, returning to work or family functioning) over others, so understanding symptom-level effects could inform treatment choices. Sykes Gilbert and colleagues frame ayahuasca — a traditional Amazonian brew containing N,N-dimethyltryptamine (DMT) plus plant-derived reversible monoamine oxidase inhibitors — as a candidate rapid-acting intervention that has shown clinically meaningful improvements in depressive symptoms after a single administration. The current study aims to examine whether self-reported changes after ayahuasca use vary across individual depressive symptoms as measured by the CES-D-10, testing the hypothesis that affective/positive-affect symptoms (e.g. hopelessness, happiness) might show larger change than cognitive, interpersonal or somatic symptoms (e.g. sleep problems, concentration). The authors argue that symptom-specific information could help clients and clinicians select interventions aligned with particular treatment priorities and that rapid onset of effect might be useful for jump-starting psychotherapy.

Participants were recruited via Facebook pages of ayahuasca-interested groups and completed an anonymous SurveyMonkey questionnaire in July–August 2018. The extracted text reports an initial sample of 143 respondents. Demographic items asked for age, gender, ethnicity and education, but detailed participant characteristics are not presented in the extracted text. The survey mentioned ayahuasca but not depression in its brief description to participants. Lifetime ayahuasca use was measured with a single question; reported use ranged from 1 to 1,100 lifetime occasions (mean 39.64, SD 135.19, skew 6.25). Depressive symptoms were assessed retrospectively using the ten-item Center for Epidemiologic Studies Depression Short Form (CES-D-10). Respondents rated how much each symptom occurred during the month before and the month after their most recent ayahuasca ceremony on 4-point scales from 1 (not at all) to 4 (a great deal). Two items (“I felt hopeful about the future” and “I was happy”) were reverse-scored. Cronbach's alpha for the difference scores was 0.849, indicating acceptable internal consistency for the change measure. Analytically, the researchers computed change scores (pre minus post) for each CES-D-10 item. Change scores ranged from −26.0 to 3.0 (mean −9.5, SD 6.2). Pre-ayahuasca CES-D-10 total scores averaged 17.02 (SD 7.0) and post-ayahuasca averaged 6.7 (SD 4.7). Two participants who reported no symptoms at baseline were omitted. The team used paired t-tests to compare pre-post differences across the ten items while controlling family-wise Type I error at P < 0.05 using Rom's procedure, a stepwise method that adjusts significance thresholds while preserving power. They screened for outliers by converting change scores to z-scores and excluded seven participants with standardized change scores > 3.0; P–P plots suggested the normality assumption for t-tests was reasonable. Lifetime ayahuasca use was treated as an ordinal variable given its skew and examined for association with change scores using Spearman correlations.

Across the sample, total depressive symptoms decreased markedly from pre- to post-ceremony: mean CES-D-10 fell from 17.02 (SD 7.0) to 6.7 (SD 4.7). Change scores had mean −9.5 (SD 6.2) and internal consistency for those change scores was high (Cronbach's alpha 0.849). After excluding two participants with no baseline symptoms and seven extreme outliers, the analytic sample was 134 (143 − 2 − 7 = 134), based on the arithmetic in the extracted text. Item-level paired t-tests showed that ayahuasca had larger effects on affective and positive-affect items — notably feelings of hopefulness, depressed mood, happiness and fear — than on several somatic, interpersonal and cognitive items, including restless sleep, loneliness and difficulty focusing. The paper presents symptoms ordered by magnitude of change, with affective symptoms at the top and somatic/cognitive symptoms at the bottom. The authors report that change scores were essentially orthogonal to lifetime ayahuasca use, indicating no consistent relationship between the number of prior ceremonies and the degree of symptom change. One exception was a small positive association between lifetime use and change on the item labelled “bothered”; this correlation reached statistical significance under a separate family-wise correction and was small in magnitude (Spearman's rho = 0.17). The extracted text does not provide exact p-values or confidence intervals for the item-level tests in the results section, nor does it reproduce the table with detailed statistics; therefore precise effect sizes by item are not available from the provided text. Overall, the pattern indicates larger reductions in affective/positive-affect symptoms than in somatic and cognitive complaints.

Sykes Gilbert and colleagues interpret their findings as evidence that ayahuasca’s retrospective impact on depressive symptoms may be symptom-specific, with larger reductions in affective and positive-affect items (e.g. hopelessness, happiness) than in somatic or cognitive symptoms (e.g. sleep disturbance, poor concentration). They situate this pattern relative to standard serotonergic antidepressants and psychotherapy, noting that some conventional medications often have limited effects on positive affect while other agents that engage norepinephrine and dopamine systems might more effectively target energy and motivation. The authors suggest that ayahuasca’s rapid onset of effect could make it useful to “jump-start” psychotherapy by providing early symptomatic relief that facilitates engagement in longer-term treatments. They caution, however, that combining ayahuasca with serotonergic medications is inadvisable because of the risk of serotonin syndrome. Acute adverse reactions to ayahuasca (nausea, vomiting, frightening psychological experiences) are acknowledged as common but typically transient, while long-term harms appear rare in screened settings. Key limitations are emphasised: the study used retrospective self-report rather than prospective or clinician-administered assessments, there was no diagnostic confirmation of major depressive disorder, the sample was self-selected and recruited online so not necessarily representative, there was no placebo or control group, and the sample size and diversity were limited. The authors therefore argue that large randomised controlled trials with longer follow-up, more comprehensive symptom assessment, and diverse samples are necessary to confirm and extend these preliminary findings. Finally, the discussion frames the results as motivating further research into symptom-level effects across different treatments, proposing that understanding which interventions preferentially relieve particular symptoms could help clinicians and patients personalise treatment choice and might expand consideration of psychedelic-assisted approaches beyond traditional diagnostic categories. The authors stop short of causal claims and call for more rigorous investigation to verify whether the observed symptom-specific pattern replicates under controlled conditions.