Post-Psychedelic Reductions in Experiential Avoidance Are Associated With Decreases in Depression Severity and Suicidal Ideation

A prospective survey study (n=358) found that psychedelics may lead to significant decreases in experiential avoidance, depression severity, and suicidal ideation.

Abstract

“Psychedelic therapy shows promise as a novel intervention for a wide range of mental health concerns but its therapeutic action is incompletely understood. In line with acceptance and commitment therapy’s (ACT’s) transdiagnostic model, qualitative research has suggested that reductions in experiential avoidance are an important component of therapeutic outcomes associated with psychedelics. However, limited research has quantitatively explored the association between decreases in experiential avoidance and therapeutic outcomes associated with psychedelics. Therefore, in two prospective studies, using convenience samples of individuals with plans to use a psychedelic, we explored the impact of psychedelic use on experiential avoidance, depression severity, and suicidal ideation, as well as relationships between changes in these outcomes. Participants (Study 1, N=104; Study 2, N=254) completed self-report questionnaires of depression severity, suicidal ideation, and experiential avoidance: 1) before using a psychedelic (in ceremonial and non-ceremonial contexts), as well as 2) 2-weeks and 3) 4-weeks after psychedelic use. Across both studies, repeated measures ANOVAs indicated significant decreases in experiential avoidance, depression severity, and suicidal ideation after psychedelic use. Furthermore, decreases in experiential avoidance were significantly associated with decreases in depression severity and suicidal ideation. These results suggest that psychedelics may lead to significant decreases in experiential avoidance, depression severity, and suicidal ideation. Additionally, these findings imply that reduced experiential avoidance may be a transdiagnostic mechanism mediating treatment success within psychedelic therapy. We conclude that integrating psychedelics with psychotherapeutic interventions that target experiential avoidance (e.g. ACT) may enhance therapeutic outcomes.”

Authors: Richard J. Zeifman, Anne C. Wagner, Rosalind Watts, Hannes Kettner, Lea J. Mertens & Robin L. Carhart-Harris

Notes

This paper is included in our ‘Top 10 Articles on Psychedelics in the Treatment of Depression‘

Also reported in Interesting Engineering and PsyPost.

A longer analysis can also be found on Psychedelic Science Review (October 2020).

“We found that use of psychedelics was associated with decreases in experiential avoidance 2-weeks later and was sustained for at least 4-weeks. These results are in line with past research indicating that administration of ayahuasca leads to increases in experiential acceptance and that psychedelic use is associated with decreases in experiential avoidance. Our results add evidence to the view that psychedelics can target putative transdiagnostic mechanisms underlying psychopathology. Based on these results, we suggest that psychedelics may show promise for the treatment of mental health concerns characterized by experiential avoidance.”

This study provides evidence for one of the possible mechanisms through which psychedelics have a long-term (at least one month) effect, by decreasing experiential avoidance. This effect is also associated with the decrease depression and suicidal ideation.

Summary

Serotonergic psychedelics are currently receiving attention within psychiatry and mental health as novel interventions for a wide range of mental health concerns, including distress associated with a life-threatening illness, substance use disorders, obsessive-compulsive disorder, depression, and suicidal ideation.

Psychedelic therapy may target underlying transdiagnostic mechanisms, but it remains unclear how psychedelics work. Identifying such mechanisms is important to improve our overall understanding of psychopathology, optimize therapeutic outcomes, and guide treatment development, refinement and delivery.

Experiential Avoidance as a Potential Transdiagnostic Mechanism

One potential transdiagnostic mechanism for the positive therapeutic outcomes associated with psychedelic therapy is reduced experiential avoidance. This is because psychedelics may lead to decreases in experiential avoidance, which is central to the development and treatment of psychopathology.

Two studies examined the relationship between improved mental health following psychedelic use and decreases on the revised Acceptance and Action Questionnaire [AAQ-II], but the AAQ-II shows poor discriminant validity from psychological distress and may be better conceptualized as an outcome related to psychological distress.

Psychedelics, Depression, and Suicidal Ideation

Approximately 350 million people worldwide struggle with depression, and suicide accounts for nearly one million deaths per year.

There are significant limitations surrounding current first-line interventions for depression and suicide, including limited evidence for the efficacy of SSRIs for individuals with mild to moderate depression severity, and delayed latency of therapeutic action.

Recent research has begun exploring psychedelic therapy as a novel intervention for depression and suicidal ideation. Psychedelics can improve and protect mental health in nonclinical populations, and more research is needed to understand the mechanisms through which psychedelics lead to positive therapeutic outcomes.

Psychedelics may reduce depression severity and suicidality via decreases in experiential avoidance. However, there is limited research on whether decreases in experiential avoidance occur in parallel with positive therapeutic outcomes.

Summary

Psychedelic use is associated with decreased experiential avoidance, depression severity, and suicidal ideation, but there is currently little understanding of whether decreases in experiential avoidance are associated with positive therapeutic outcomes following psychedelic use.

Procedure and Participants

We recruited participants via online advertisements, email newsletters, and online forums. Participants were sent emails at three key time points (baseline, 2-weeks, and 4-weeks post-psychedelic use) reminding them to complete the online surveys.

We recruited 279 individuals from April 2018 to May 2019 and removed 104 individuals that did not respond to the surveys, reported plans to use substances that are not considered serotonergic psychedelics, and had a score of 0 on the Quick Inventory of Depressive Symptoms at baseline.

Experiential Avoidance

Experiential avoidance was measured using the Brief Experiential Avoidance Questionnaire (BEAQ), which is a 15-item self-report measure. Higher scores indicate higher levels of experiential avoidance.

Depression Severity

Depression severity was measured using the Quick Inventory of Depressive Symptoms (QIDS), a 16-item self-report measure that assesses the presence of nine key diagnostically relevant symptoms of major depression over the previous 7 days.

Suicidal Ideation

Suicidal ideation was measured using the Suicidal Ideation Attributes Scale and the QIDS-suicidality item. The SIDAS and QIDS-SI are 5-item self-report measures of suicidal ideation and have been shown to have strong internal consistency and good convergent validity.

Analyses

We used non-parametric tests when appropriate and created a composite measure of suicidal ideation by summing Z-scores for the SIDAS and QIDS-SI.

Hypothesis #1: Decreases in Experiential Avoidance, Depression Severity, and Suicidal Ideation Over Time

We conducted three general linear models repeated measures ANOVAs with Bonferroni corrections to examine whether there were decreases in experiential avoidance, depression severity, and suicidal ideation afterpsychedelicuse.

Hypothesis # 2: Association Between Decreases in Experiential Avoidance, Depression Severity, and Suicidal Ideation

We used Spearman’s rho to determine whether decreases in experiential avoidance were associated with decreases in depression severity and suicidal ideation.

Descriptive Statistics

Participants reported planning to use psilocybin/magic mushrooms/truffles, LSD/1PLSD, ayahuasca, DMT, 5-MeO-DMT, 4-AcO-DMT, 5-MeO-MiPT, more than one psychedelic, and either psilocybin or LSD.

Hypothesis 1a: Decreases in Experiential Avoidance Over Time

We examined whether there were significant decreases in experiential avoidance over time. The results indicated that there were significant decreases from baseline to 2-weeks and 4-weeks, with no significant changes from 2-weeks to 4-weeks.

Among individuals with mild to very severe depression severity, experiential avoidance decreased significantly over time, with no significant changes from baseline to 4-weeks.

Hypothesis 1b: Decreases in Depression Severity Over Time

We examined whether there were significant decreases in depression severity over time. The results indicated that there were significant decreases from baseline to 2-weeks and 4-weeks, with no significant changes from 2-weeks to 4-weeks.

Individuals with mild to very severe depression severity had significant decreases in depression severity over time, with no significant changes from baseline to 2-weeks or 4-weeks.

Hypothesis 1c: Decreases in Suicidal Ideation Over Time

We examined whether there were significant changes in suicidal ideation over time. A GLM repeated measures ANOVA indicated significant decreases in suicidal ideation over time, with significant decreases from 2-weeks to 4-weeks.

Individuals with mild to very severe depression severity had decreased suicidal ideation over time, with significant decreases from baseline to 2-weeks and 4-weeks.

Hypothesis 2a: Association Between Decreases in

Results indicated that experiential avoidance was associated with depression severity, and that decreases in experiential avoidance were associated with decreases in depression severity at 2-weeks and 4-weeks.

Procedures and Participants

To supplement Study 1, we conducted a separate prospective cohort study of individuals attending psychedelic ceremonies. This study was designed to provide data from a second independent study and sample.

A study was designed to ask individuals planning to attend psychedelic ceremonies if they would complete an online survey. The study received its own approval from Imperial College London’sImperial College Research Ethics Committee and the Joint Research Compliance Office.

Participants were recruited from April 2018 to June 2019. 254 individuals were included in the analysis, and 32 individuals were removed for not responding to any of the outcome variables at baseline or both follow-up surveys.

Measures

In contrast to Study 1, we measured experiential avoidance, depression severity, suicidal ideation, and suicide risk at baseline and 4-weeks.

Analyses

The variables in Study 2 were not normal, so non-parametric tests were used when appropriate. The BEAQ and SIDAS were not measured at 2-weeks, so they are not included in analyses for that time point.

Descriptive Statistics

Participants reported planning to use psilocybin/magic mushrooms/truffles, ayahuasca/yage, San Pedro, and DMT. Four individuals reported planning to use more than one psychedelic.

Hypothesis 1a: Decreases in Experiential Avoidance Over Time

We examined whether there were significant decreases in experiential avoidance over time. We found that there were, with a moderate effect size.

Severity Over Time

We examined whether there were significant decreases in depression severity over time. A GLM repeated measures ANOVA indicated that depression severity decreased significantly from baseline to 2-weeks and 4-weeks, but not from 2-weeks to 4-weeks.

Individuals with mild to very severe depression severity had significant decreases in depression severity over time, with no significant changes from baseline to 2-weeks or 4-weeks.

Hypothesis 1c: Decreases in Suicidal Ideation Over Time

We examined whether there were significant decreases in suicidal ideation over time. We found that there were, with a moderate effect size.

DISCUSSION

In two separate studies, participants with subclinical depression severity experienced significant decreases in depression severity and suicidal ideation 4-weeks after psychedelic use. Importantly, the effects of psychedelics were sustained for at least 1-month post-psychedelic use.

Exploring the Role of Experiential Avoidance

Despite growing evidence that psychedelics have therapeutic potential, there remains a limited understanding of the underlying psychological mechanisms that account for their therapeutic effects. Psychedelics may show promise for the treatment of mental health concerns characterized by experiential avoidance.

We found that decreases in experiential avoidance were significantly associated with decreases in depression severity and suicidal ideation, and that increasing emotional responsiveness was a key theme associated with therapeutic change among individuals with treatment-resistant depression.

We suggest that integrating psychedelics with psychotherapeutic interventions that specifically target experiential avoidance may help to enhance and prolong the effectiveness of psychedelic therapy.

Limitations and Future Research

This study was an uncontrolled study lacking a control group or randomization procedure. As such, results may have been driven by factors other than psychedelic use, and further research is needed to assess the role that contextual variables may play in mediating outcomes.

This study examined the effects of psychedelic use on experiential avoidance, depression severity, and suicidal ideation in a convenience sample of individuals with interest in using psychedelics. However, further research is required to assess whether these effects translate to clinical populations and controlled studies.

Consistent with RDoC recommendations, research should focus on the neurobiological basis of experiential avoidance and related phenomena, and on ACT exercises that increase cognitive flexibility.

In conclusion, psychedelic use in ceremonial and non-ceremonial settings was associated with decreases in depression severity, suicidal ideation, and experiential avoidance.