Sustained, multifaceted improvements in mental well-being following psychedelic experiences in a prospective opportunity sample

This survey (n=654 start; n=64 end) found that those who used psychedelics (by themselves; naturalistic observational study) improved in ‘being well’ and ‘staying well’, but found no changes in ‘spirituality’. The study ran for two years and also measured the well-being of the participants before, two weeks after, and four weeks after the experience.


Introduction: In the last fifteen years, psychedelic substances, such as LSD and psilocybin, have regained legitimacy in clinical research. In the general population as well as across various psychiatric populations, mental well-being has been found to significantly improve after a psychedelic experience. Mental well-being has large socioeconomic relevance, but it is a complex, multifaceted construct.

Methods: In this naturalistic observational study, a comprehensive approach was taken to assessing well-being before and after a taking a psychedelic compound to induce a ‘psychedelic experience’. Fourteen measures of well-being related constructs were included in order to examine the breadth and specificity of change in well-being. This change was then analysed to examine clusters of measures changing together. Survey data was collected from volunteers that intended to take a psychedelic. Four key time points were analysed: one week before and two weeks, four weeks, and two years after the experience (N = 654, N = 315, N = 212, and N = 64 respectively).

Results: Change on the included measures was found to cluster into three factors which we labelled: 1) ‘Being well’, 2) ‘Staying well’, and 3) ‘Spirituality’. Repeated Measures Multivariate Analysis of Variance revealed all but the spirituality factor to be improved in the weeks following the psychedelic experience. Additional Mixed model analyses revealed selective increases in Being Well and Staying Well (but not Spirituality) that remained statistically significant up to two years post-experience, albeit with high attrition rates. Post-hoc examination suggested that attrition was not due to differential acute experiences or mental-health changes in those who dropped out versus those who did not.

Discussion: These findings suggest that psychedelics can have a broad, robust and sustained positive impact on mental well-being in those that have a prior intention to use a psychedelic compound. Public policy implications are discussed.

Authors: Keri Mans, Hannes Kettner, Eline C. Haijen, Mendel Kaelen, David Erritzoe & Robin L. Carhart-Harris


If we step outside of the lab for a moment, can we find the same improvement in well-being? Can we find the sustained positive impact on mental well-being that many studies have reported on? That is what the current study tries to grapple with.

A survey among those who took psychedelics questioned the participants on fourteen aspects of well-being. They measured this a week before the experience, two and four weeks after, and two years later. At the first moment, 654 participants answered the questions, after two years they were able to gather results from 64 people.

This is what changed in their well-being

  • The themes ‘being well’ and ‘staying well’ improved and stayed elevated throughout the study
  • The theme ‘spirituality’ didn’t change from the baseline measure
  • Changes in well-being negatively correlated with psychological inflexibility and depressive symptoms

A survey study like this is able to answer the question of what happens in real life for those who use psychedelics. The current study was done with those who had already done psychedelics before (90%) and a future study could possibly see if the same results (or better results) can be found for those who haven’t used psychedelics before. And finding out what specifically, for those without mental illness, during the psychedelic experience leads to these positive outcomes.

As the authors say in the introduction and conclusion, understanding how psychedelics can help those who are ‘well’ could help strengthen them against adversity (e.g. lockdowns, grief). And in turn this could lead to fewer people falling into the ‘unwell’ category. And who doesn’t want their well-being to improve?

This study is a follow-up to Haijen and colleagues (2018) which didn’t include the follow-up data and grouping of themes.


Mental well-being can be seen as (in part) the opposite of mental illness. And where mental illness is currently one of the leading causes of disability in the world, improving mental well-being could move people back up this continuum towards the more positive side.

The current study defines mental well-being as ‘positive mental health’ or ‘flourishing’. And at the same time recognizes that no single definition has been generally accepted.

The paper investigates this side of the spectrum (whereas many other studies focus on mental illness). The authors argue that psychedelics may be a tool to help improve the well-being of those not (currently) suffering from mental illness.

“It is suggested that, besides alleviating symptoms in clinical populations, initiatives and interventions for people that are already “well” could serve to further promote wellness and mitigate risk of mental illness.”


The participants took part in the 2017 Psychedelic Survey. They had planned to partake in a psychedelic experience and were then queried at six different time-points (-7, -1, +1, +14, +28d, +2y).


Well-being scores improved significantly. They also correlated with other such as self-esteem, mindfulness, resilience, emotional stability, gratitude, presence (meaning). The inverse was true (negative correlation) for scores of psychological inflexibility, and depressive symptoms.

Based on this data, the researchers found three underlying factors (exploratory factor analysis) and dubbed them ‘being well’, ‘staying well’, and ‘spirituality’. Of these, the first two were found to be sustained (higher) two years after the experience.

An analysis of the drop out (attrition) of participants didn’t show anything to worry about (e.g. that only the most positive participants filled in the last survey).


“These findings lend support to the view that psychedelics have a general positive effect on well-being; promoting psychological wellness and resilience in the medium to long-term.”

The current study was done ‘in the field’ which means that the ecological validity is high. Or in other words, it generalizes to others who are using psychedelics by themselves outside of clinical trials.

There are however limitations to the current methodology. The participants were self-selection (a subsection of those who already use psychedelics, and want to fill in a survey, etc). And although no abnormalities were found in the data, the high attrition rate (leaving about 10% of participants at the 2 year follow-up) could lead to a response bias.

Used with care, psychedelics may have potential to complement early intervention or prophylactic strategies, e.g., using lowdose psychedelic therapy to improve receptivity to, and enhance the action of, mindfulness-based practises designed for this purpose.



Mental well-being is a broad construct that includes both positive mood and good general functioning. It is inversely related to mental illness, and efforts to promote and maintain well-being should be considered a priority area for policy makers and healthcare systems.

There are various interventions aiming to promote and protect mental health, including pharmacotherapy, various psychotherapies, mindfulness and life skills training. One such intervention is psychedelic therapy, which involves supervised psychedelic drug experiences bookended by psychological support.

Recent studies in clinical and healthy populations have revealed that just one/two psychedelic dosing sessions can improve well-being and reduce rates of psychological distress and suicidality. These findings are suggestive of the prophylactic value of psychedelic therapy, as well as its relevance for positive psychology.

Well-being is a complex construct that encompasses both feeling good and functioning well. There is no single definition of well-being, but researchers have tried to narrow it down to positive mental health or flourishing.

There are many self-report measures designed to assess well-being, but many are influenced by clinical classification systems that may not translate well to the general population. A comprehensive approach to well-being assessment is suggested, which combines measures of underlying and related constructs.

Psychedelics have been shown to have positive effects on several aspects of well-being, including gratitude, life meaning/purpose, coping, and interpersonal closeness.

We conducted a naturalistic, observational study using opportunity sampling and online data collection to assess the effects of psychedelics on well-being. The results may have implications for the potential prophylactic value of psychedelics via their capacity to promote and maintain mental well-being.


This study used data from an anonymous, prospective cohort study that was conducted between March and November 2017 through the online platform “Psychedelic Survey”. Follow-up data was collected between July and August 2019 to assess longer term effects.


The sample consisted of individuals who planned to undergo a psychedelic experience. They gave informed consent electronically.

The researchers included participants who were >18 years old, had a good comprehension of the English language, and intended to take one of the following psychedelic drugs in the near future.


The study was advertised online using social media outlets and included six surveys completed at different points in time, before and after the day the psychedelic compound was taken.

Type of Measures

14 measures of well-being were included in the main analyses for the current study, including the Warwick-Edinburgh Mental Well-being Scale, Quick Inventory of Depressive Symptoms, Rosenberg Self-Esteem Scale, Revised Life Orientation Test, Ten-item Personality Inventory, Emotional Stability subscale, and Meaning in Life Questionnaire, Presence subscale.

Selection of Outcome Measures for Main Analyses

Previous literature guided the selection of 14 measures of well-being, including the Warwick-Edinburgh Mental Well-being scale, which is a generic conception of mental well-being capturing three key concepts: positive affect, psychological functioning, and interpersonal relationships.

Planned Analyses

Correlation analyses, general linear models, and dimension reduction analyses were carried out to investigate the broader construct of well-being in the context of psychedelic drug use. Data from survey time points 1, 4, and 5 was used in the main analyses.


Correlation analyses were conducted to explore whether the selected secondary measures were indeed (closely) related to the primary measure, as well as to investigate covariance between the secondary measures.

To assess psychedelic-induced changes on the assessed outcome measures, all 14 measures were included as dependent variables in a repeated-measures multivariate analysis of variance (RM MANOVA), with time as within-subjects factor.

Dimension Reduction

To investigate factors underlying well-being that appeared to change together over time in relation to a psychedelic experience, exploratory factor analysis was carried out on standardised change scores. The type of EFA used was principal axis factoring (PAF) with oblique (Promax) rotation with a Kappa value of 4.

Factor Scores

Factor scores were computed for each of the three time points and normalised so they ranged between 0 and 1.

Follow-Up Data Analysis

A Linear Mixed Model was used to test changes across the entire duration of the study, leveraging its ability to better accommodate missing data.

Attrition Bias

For addressing potential attrition biases, we assessed changes in scores on five selected variables from baseline to the 4-week endpoint. These changes might inform on how positive/negative one rated their experience, which could be an incentive to either or not drop out.

Guidelines Followed

The effect sizes of Pearson correlation coefficients and partial eta squared were interpreted in accordance with the guidelines of r = 0.10, r = 0.30, and r = 0.50, respectively.


The correlations between primary and secondary well-being measures were significant for all measures except for depressive symptoms. Positive correlations were found between spirituality and self-esteem and optimism and resilience, and negative correlations were found between psychological inflexibility and self-esteem.


All main measures were significant, except spirituality (both SpREUK-SF-T and STS-U) and compassion (SCBCS). The four largest univariate effect sizes were found for depressive symptoms, optimism, self-esteem, and general mental well-being.

Exploratory Factor Analysis

After rotation, commonalities were extracted, and reliability measures were calculated. Three factors were determined: factor 1 represented changes associated with “Being well”, factor 2 represented changes associated with “Staying well”, and factor 3 reflected changes related to trait “Spirituality”.

The reliability of the three factors was 0.81, 0.72, and 0.41 using change scores and 0.88, 0.82, and 0.77 using baseline scores.

Factor Changes

Three factors were identified that were assessed for change over time. Repeated measures multivariate analysis of variance showed a significant within-subjects effect for factors 1 and 2, with moderate effect sizes, but non-significant results for changes in factor 3.

Change Over Time

Linear Mixed Model analyses indicated that Being Well and Staying Well increased over all four time points, but that baseline scores fell to trend-level at TP6.

Attrition (Bias)

In total, 677 out of 741 participants dropped out at or prior to the final follow-up survey at 2 years post-experience. 32 participants completed all six time points.

To test for potential attrition biases, a Multivariate Analysis of Variance was run. No significant differences were found between TP6 completers and non-completers on the selected factor change scores and two of the three subjective measures.


The present study found that those that had a prior intention to use a psychedelic compound had increased well-being scores 2 years after the experience, and that these increases were reflected in both factors Being Well and Staying Well.

Psychedelics seem to have a positive effect on well-being, promoting psychological wellness and resilience in the medium to long-term. This could be a priority area for mental healthcare, considering the increasing prevalence of mental illness and the growing costs of healthcare associated with mental illness.

Mindfulness-based and positive psychology approaches are being explored as an early intervention strategy, with apparent success in improving well-being. A parallel can be seen between the improvement of mindfulness capacities through meditation and therapeutic interventions, and through psychedelic experiences.

Early intervention in mental health is being increasingly discussed, but the risks associated with psychiatric drug interventions in young people need to be factored against the merits of early intervention.

The present study identified a specific factor containing validated scales pertaining to “Staying Well” that was significantly increased at 2 and 4 weeks after the psychedelic experience and remained significantly elevated at 2 years. This finding is particularly intriguing as it has implications for the long-term positive psychological effects of psychedelics.

Despite historical negative stigma surrounding psychedelics, we recognise that an early intervention trial may be difficult to develop. However, the potential for long-term psychological benefit must be weighed against the risk of severe iatrogenesis.

The present study investigated which measures of well-being were most sensitive to change. This is important for future studies to avoid high attrition rates.

Results revealed that the most sensitive measures were those classified under the Being well factor, and can be usefully employed in future studies.

We used the diagnostically validated QIDS-SR16 to measure depression severity and the WEMWBS to measure general well-being. There were strong correlations between the different measures of well-being when looking at scores on one single time point (baseline).

The five scales loading onto Staying Well were generally less sensitive to change than the six Being Well questionnaires, but they can yield additional information. The CAMS-R may be the more useful of these two scales when combined with the QIDS-SR16 and WEMWBS.

The third factor, Spirituality, contained three measures that were less sensitive to change after psychedelic use in the current sample. This could be due to the fact that the measures are trait-based and do not enquire about spiritual experiences per se.

The lack of experimental control was a major limitation of this study, and expectancy was a major potential source of bias.

This study had several limitations, such as a small sample size, a high attrition rate, and a focus on people intending to take psychedelics through their own initiative. However, the results indicate that participants experiencing a more challenging experience under the psychedelic were not more likely to drop out.

This study population was heterogeneous, and included people with different substances, set and setting, and a high distribution of lifetime mental illness diagnoses. Future studies could look at predictors of change, such as intentions.

The present study found that comprehensive positive changes in well-being were observed following a psychedelic experience. The findings support the view that psychedelic use can both promote and protect psychological wellness.


Authors associated with this publication with profiles on Blossom

Mendel Kaelen
Mendel Kaelen is a neuroscientist and entrepreneur, researching and developing a new category of psychotherapeutic tools for care-seekers and care-providers. Mendel has researched the incomparable effects of music on the brain during LSD-assisted psychotherapy. His work has determined how LSD increases enhanced eyes-closed visual imagery, including imagery of an autobiographical nature. This gives light to how music can be used as another dimension in helping psychotherapists create the ideal setting for their patients.

David Erritzoe
David Erritzoe is the clinical director of the Centre for Psychedelic Research at Imperial College London. His work focuses on brain imaging (PET/(f)MRI).

Robin Carhart-Harris
Dr. Robin Carhart-Harris is the Founding Director of the Neuroscape Psychedelics Division at UCSF. Previously he led the Psychedelic group at Imperial College London.


Institutes associated with this publication

Imperial College London
The Centre for Psychedelic Research studies the action (in the brain) and clinical use of psychedelics, with a focus on depression.

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Predicting responses to psychedelics: a prospective study
This longitudinal survey study (n=654 > 535 > 379 > 315 > 212, with increasing dropout) gathered data from individuals at five different time points before and after they undertook a preregistered psychedelic experience, and assessed variables related to personality traits, intentions, and the set and setting to predict the acute effects of taking the psychedelic, as well as long-term outcomes of subjective well-being. Baseline trait variables, such as absorption, strongly influenced long-term well-being. However, acute variables such as the intention and intensity of having mystical experiences also positively influenced well-being up to four weeks after the psychedelic experience.

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