A Single Dose Of Ayahuasca Modulates Salivary Cortisol In Treatment-Resistant Depression

Major depressive disorder (MDD) is common and linked to dysregulation of the hypothalamic–pituitary–adrenal (HPA) axis, with studies reporting both hypercortisolism and hypocortisolism depending on factors such as depression subtype, severity, sex, illness duration and socioeconomic status. Cortisol measures, including the cortisol awakening response (CAR), have been used as biomarkers of depression and treatment response, though findings are heterogeneous. Psychedelics, and specifically ayahuasca, have recently shown rapid antidepressant effects in early clinical studies; ayahuasca contains N,N-dimethyltryptamine (N,N-DMT) plus β-carboline MAO inhibitors and has a long history of ritual medicinal use in Brazil and South America. Galvão and colleagues set out to examine how a single dose of ayahuasca affects cortisol physiology in people with treatment-resistant depression and in healthy volunteers. They tested two primary hypotheses: that patients and controls would differ at baseline in plasma cortisol and awakening salivary cortisol response (AUC), and that ayahuasca (but not placebo) would acutely raise cortisol during the dosing session and alter cortisol measures 48 hours after ingestion, with cortisol responses correlating with clinical improvement in depressive symptoms.

This was a randomised, double-blind, placebo-controlled, parallel-arm trial conducted at a university hospital in Natal, Brazil, and registered as NCT02914769. Seventy-one volunteers were enrolled: 43 healthy controls (19 men, 24 women) and 28 patients with treatment-resistant major depression (7 men, 21 women). Treatment resistance was defined as inadequate response to at least two antidepressants from different classes. Exclusion criteria included prior ayahuasca experience, certain medical or neurological disorders, bipolar or psychotic history, substance abuse and pregnancy. Selected patients were in a moderate–severe depressive episode (HAM-D ≥ 17) and underwent a pharmacological washout of about two weeks; they were not taking antidepressants during the trial but were taking benzodiazepines. Participants were randomised 1:1 to receive a single oral dose of ayahuasca or a placebo liquid designed to mimic the appearance and taste but without psychoactive properties. The ayahuasca batch averaged 0.36 mg/mL N,N-DMT, 1.86 mg/mL harmine, 0.24 mg/mL harmaline and 1.20 mg/mL tetrahydroharmine; dose was 1 mL/kg adjusted to deliver approximately 0.36 mg/kg N,N-DMT. During the dosing session subjects remained resting with eyes closed and could listen to a predefined music playlist; two researchers provided support. Biological measures comprised awakening salivary cortisol (three samples collected at awakening: +5, +30 and +45 minutes; area under the curve, AUC, calculated from these) and fasting morning total plasma cortisol collected at 07:00. Saliva and plasma were stored at −80°C and assayed by ELISA. Clinical depression severity was measured with MADRS at baseline (D0) and 48 hours after dosing (D2). Acute salivary cortisol response during the dosing session was measured immediately before dosing and at +1h40. Statistical analysis used log-transformed cortisol values; baseline group comparisons used ANCOVA with sex as covariate, correlations used Spearman tests, acute salivary responses were compared with Mann–Whitney tests, and longitudinal analyses employed General Linear Models (GLM) with Fisher post-hoc tests. Significance threshold was p < 0.05.

Baseline (D0) comparisons showed that patients with treatment-resistant depression had lower awakening salivary cortisol AUC and lower total plasma cortisol than healthy controls. Specifically, awakening salivary AUC was 49.4 ± 8.3 cm2 in patients (n=20) versus 62.5 ± 6.3 cm2 in controls (n=41); the ANCOVA main effect of group was significant (F=9.75, p=0.002) and sex had no effect. Total plasma cortisol averaged 15.12 ± 1.73 μg/dl in patients (n=28) and 19.52 ± 1.37 μg/dl in controls (n=43), with a significant group effect (F=4.71, p=0.03) independent of sex. At baseline control subjects showed a positive correlation between plasma cortisol and salivary AUC (Spearman rs=0.54, p<0.05), whereas no such correlation was found in patients. The extracted text reports that 61% of patients had ‘‘relative’’ hypocortisolemia (below 15 μg/dl) and 22.22% had ‘‘true’’ hypocortisolemia (below 10 μg/dl) using the study’s cutoff values. During the dosing session, salivary cortisol measured at +1h40 increased substantially in both healthy volunteers and patients who received ayahuasca compared with those who received placebo; the paper reports a ‘‘major acute increase’’ but the extracted text does not provide exact magnitude values. Two days after dosing (D2) the GLM reported a significant Group×Treatment×Days interaction for awakening salivary AUC (F=4.57, p=0.03). Post-hoc comparisons showed that patients who received ayahuasca had an awakening salivary AUC at D2 (59.4 ± 12.7 cm2) that was similar to healthy subjects who received ayahuasca (50.1 ± 8.2 cm2) and to controls who received placebo (61.9 ± 8.9 cm2). By contrast, patients who received placebo continued to show a lower AUC at D2 (41.2 ± 14.8 cm2) relative to placebo-treated controls (61.9 ± 8.9 cm2; Fisher post-hoc p=0.03). Sex did not influence these results according to the reported analyses. Total plasma cortisol showed no significant changes between D0 and D2 within groups or treatments and no group or treatment effects were detected in the GLM for plasma cortisol. Clinically, the extracted text reports that 77% of patients in the ayahuasca group and 64% in the placebo group met the study’s definition of response at D2 (clinical response defined as ≥50% reduction in baseline depression scale scores). The paper lists MADRS scores at D0 (32.67 ± 6.31) and reports values at D2 (55.79 ± 32.14 for ayahuasca and 61.42 ± 25.7 for placebo), but these D2 figures appear inconsistent with the baseline mean and the stated response rates; the extraction does not clarify whether these numbers represent raw scores, percent change or another metric. The investigators did not find correlations between cortisol changes (acute or at 48 hours) and clinical improvement in depressive symptoms. Individual responses in both AUC and plasma cortisol showed large variability.

Galvão and colleagues interpret their findings as evidence that patients with treatment-resistant depression displayed basal hypocortisolemia and a blunted cortisol awakening response compared with healthy controls, and that a single ayahuasca dose produced an acute rise in salivary cortisol and, by 48 hours, normalised the awakening salivary cortisol AUC in patients. The authors note that this normalisation was not observed in patients who received placebo. They discuss cortisol’s physiological role in stress adaptation and note that both excess and deficiency of cortisol have adverse effects; the presence of hypocortisolemia in their patient sample is linked in the paper to possible long-term HPA axis maladaptation, cumulative life stressors, socioeconomic disadvantage and prior chronic antidepressant exposure. The discussion situates the acute cortisol rise after ayahuasca within prior reports that serotonergic psychedelics and DMT can elevate cortisol acutely, and proposes that ayahuasca’s pharmacology (N,N-DMT and β-carbolines increasing serotonergic tone) could mediate acute CRH/ACTH and cortisol release. The authors highlight that salivary awakening AUC was more sensitive than total plasma cortisol to both baseline group differences and to the treatment effect, and therefore may be a more robust biomarker for some purposes; however, they caution against using salivary cortisol alone as a diagnostic marker because altered cortisol patterns occur across disorders and because they did not observe a correlation between cortisol shifts and symptom improvement. Key limitations acknowledged by the authors include large individual variability in cortisol measures, the complex aetiology of hypocortisolemia, potential confounding by long-term antidepressant exposure and socioeconomic factors in the sample, and the need for further and longer-term studies to establish clinical relevance. They conclude that the observed modulation of awakening salivary cortisol by ayahuasca, alongside clinical response signals, supports further clinical research into psychedelics for mood disorders.