Decreases in State and Trait Anxiety Post-psilocybin: A Naturalistic, Observational Study Among Retreat Attendees

This naturalistic study (n=52) assessed the effects psilocybin has on measures of state and trait anxiety among retreat participants with subclinical levels of anxiety. Average psilocin consumption across individuals was 27.1 mg. The morning after the ceremony, medium reductions in both state and trait anxiety were observed and these reductions persisted for 1-week. Higher ratings of ego dissolution and changes in neuroticism were the strongest predictors of these reductions.


“Anxiety disorders are the most common type of psychiatric disorders among Western countries. Evidence-based treatment modalities including pharmacological and cognitive-behavioural therapy result in deficient treatment responses. Historical and recent research suggests psychedelic drugs may be efficacious in alleviating anxiety-related symptoms among healthy and clinical populations. The main aim of the present study was an investigation of the effects of psilocybin-containing truffles, when taken in a supportive group setting, on ratings of state and trait anxiety across self-reported healthy volunteers. Attendees of psilocybin ceremonies were asked to complete a test battery at three separate occasions: before the ceremony (baseline), the morning after, and 1 week after the ceremony. The test battery included questionnaires assessing state and trait anxiety (State-Trait Anxiety Inventory), mindfulness capacities (Five Facet Mindfulness Questionnaire), and personality (Big Five Inventory). Additionally, the psychedelic experience was quantified with the Persisting Effects Questionnaire and the Ego Dissolution Inventory. The total amount of psilocybin-containing truffles consumed by each participant was recorded, and a sample of the truffles was analyzed to determine psilocin concentrations. Fifty-two attendees (males = 25; females = 25; others = 2) completed parts of the baseline assessment, 46 (males = 21; females = 24; others = 1) completed assessments the morning after the ceremony, and 23 (males = 10; females = 13) completed assessments at the 1-week follow-up. Average psilocin consumption across individuals was 27.1 mg. The morning after the ceremony, we observed medium reductions in anxiety measures (both state and trait) compared to baseline (d¯d¯ = 6.4; p < 0.001 and d¯d¯ = 6; p = 0.014, respectively), which persisted over a 1-week period post-ceremony (d¯d¯ = 6.7; p = 0.001 and d¯d¯ = 8.6; p = 0.004, respectively). At 1 week post-ceremony, the non-judging facet of the mindfulness scale was increased (d¯d¯ = 1.5; p = 0.03), while the personality trait neuroticism decreased (d¯d¯ = 5.2; p = 0.005), when compared to baseline. Additionally, we found ratings of ego dissolution (mean: 59.7, SD: 28.3) and changes in neuroticism to be the strongest predictors of reductions in state and trait anxiety, respectively. In sum, results suggest rapid and persisting (up to 1 week) anxiolytic effects in individuals with sub-clinical anxiety symptoms, which are related to the acute experience of ego dissolution, as well as lasting changes in trait neuroticism. Results also add support to the feasibility and potential efficacy of group sessions with psychedelics. To understand whether these effects extend to wider populations suffering from heightened anxiety, and the mechanisms involved, further experimental research is needed.”

Authors: Maggie K. Kiraga, Kim P. C. Kuypers, Malin V. Uthaug, Johannes G. Ramaekers & Natasha L. Mason

Study details

Compounds studied

Topics studied

Study characteristics

52 Humans


Authors associated with this publication with profiles on Blossom

Kim Kuypers
Kim Kuypers is a researcher at Maastricht University. Her work is concerned with understanding the neurobiology underlying flexible cognition, empathy, and well-being. One of the main ways she does is with the use of psychedelics.

Johannes Ramaekers
Johannes Ramaekers is a professor at Maastricht University his work focuses on behavioral toxicology of drugs and combines methods from psychopharmacology, forensic toxicology and neuroscience to determine drug-induced changes in human performance. Some of this research is done with DMT.

Natasha Mason
Natasha Mason is interested in elucidating the neurobiological and cognitive mechanisms of (psychedelic) drugs by utilizing multimodal study designs, with a particular focus on substances that may hold therapeutic value.


Institutes associated with this publication

Maastricht University
Maastricht University is host to the psychopharmacology department (Psychopharmacology in Maastricht) where various researchers are investigating the effects of psychedelics.

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