Validation of the Psychological Insight Scale: A new scale to assess psychological insight following a psychedelic experience

This survey study (n=279) developed and validated a new scale to measure participants psychological insight after a psychedelic experience: the Psychological Insight Scale (PIS). It was found the PIS is complementary to current measures used in psychedelic studies while insight, as measured by the PIS, was found to mediate the long-term psychological outcomes after a psychedelic experience.


“Introduction: As their name suggests, ‘psychedelic’ (mind-revealing) compounds are thought to catalyse processes of psychological insight; however, few satisfactory scales exist to sample this. This study sought to develop a new scale to measure psychological insight after a psychedelic experience: the Psychological Insight Scale (PIS).

Methods: The PIS is a six- to a seven-item questionnaire that enquires about psychological insight after a psychedelic experience (PIS-6) and accompanying behavioural changes (PIS item 7). In total, 886 participants took part in a study in which the PIS and other questionnaires were completed in a prospective fashion in relation to a planned psychedelic experience. For validation purposes, data from 279 participants were analysed from a non-specific ‘global psychedelic survey’ study.

Results: Principal components analysis of PIS scores revealed a principal component explaining 73.57% of the variance, which displayed high internal consistency at multiple time points throughout the study (average Cronbach’s α = 0.94). Criterion validity was confirmed using the global psychedelic survey study, and convergent validity was confirmed via the Therapeutic-Realizations Scale. Furthermore, PIS scores significantly mediated the relationship between emotional breakthrough and long-term well-being.

Conclusion: The PIS is complementary to current subjective measures used in psychedelic studies, most of which are completed in relation to the acute experience. Insight – as measured by the PIS – was found to be a key mediator of long-term psychological outcomes following a psychedelic experience. Future research may investigate how insight varies throughout a psychedelic process, its underlying neurobiology and how it impacts behaviour and mental health.”

Authors: Joseph M. Peill, Katie E. Trinci, Hannes Kettner, Lea J. Mertens, Leor Roseman, Christopher Timmermann, Fernando E. Rosas, Taylor Lyons & Robin L. Carhart-Harris



Research demonstrates that ‘peak experiences’ (including ’emotional breakthrough’) may be important mediators of long-term psychological changes after psychedelic use, and that insight may be correlated with therapeutic outcomes such as decreased depressive symptoms and improved mental health.

The Psychological Insight Scale (PIS) was developed to measure psychological insight after a psychedelic experience.

Many studies have suggested that insight is a common, if not fundamental, property of the psychedelic experience, and that the word ‘psychedelic’ itself refers to insight-promotion as a core drug property.

Measuring therapeutic-relevant aspects of the psychedelic experience

The nature and quality of the acute psychedelic experience mediates long-term psychological changes post-experience. Peak experiences, challenging experiences and emotional breakthroughs are particularly pertinent aspects of the acute experience, bearing relevance to subsequent long-term psychological changes.

The Mystical Experience Questionnaire, originally derived from the States of Consciousness Questionnaire, captures specific qualities of the psychedelic peak experience, which have been associated with positive outcomes in both healthy groups and patient populations.

Psychologically challenging experiences, characterised by psychological struggle or distress, have been reported in various psychedelic studies. The Challenging Experience Questionnaire (CEQ) was developed to capture this phenomenon, but did not predict subsequent changes in psychological well-being.

Psychodynamic psychology holds that a surrender of psychological resistance is required for emotional breakthrough, and the Emotional Breakthrough Inventory (EBI) was developed to address this phenomenon via a focused quantitative scale.


Developing insight into one’s own thoughts, feelings and behaviours is thought to be a key factor in improving mental well-being. This is because greater self-understanding allows one to respond to stresses and negative experiences adaptively, promoting greater well-being and life satisfaction.

The Insight subscale of the self-reflection and insight scale (SRIS-IN) does not allow for an assessment of changes in insight in relation to a time-limited experience (e.g. a psychedelic experience). The less commonly used Therapeutic-Realizations Scale (TRS) is better suited to assess psychological insights following a psychedelic experience.

A Psychological Insight Questionnaire was recently devised to assess insights gained during a psychedelic session. It is predicted that the Psychological Insight Scale may have the greatest value as a subacute predictor or mediator of long-term mental health outcomes.

Current definitions of insight follow the idea of ‘novel’ thoughts or realisations. The PIS assesses personal psychological insight.

The present study aimed to psychometrically validate a novel PIS that measures psychological insight following psychedelic experiences. It was also validated in a second prospective sample of individual psychedelic users.

The acute psychedelic experience will significantly predict post-acute psychological insight, and PIS scores will significantly mediate this relationship.


The psychedelic drugs used were taken by the individual’s accord in these studies.

Psychometric measures

A six-item questionnaire to assess acute emotional breakthroughs, based on the Visual Analogue Scale (VAS) scoring system. The EBI score has demonstrated high internal consistency.

The revised 30-item MEQ assesses the acute mystical-type experience via a 5-point Likert-type scale, and has demonstrated high internal consistency and strong predictive validity with respect to long-term psychological measures such as personal meaning.

Barrett et al. (2016) developed the CEQ, a 26-item, 5-point Likert-type scale with seven subscales investigating Fear, Paranoia, Insanity, Physical Distress, Isolation, Death and Grief.

The Warwick – Edinburgh Mental Well-Being Scale is a validated, 14-item scale that assesses positive mental health. It can be used to investigate the improvement or change in well-being within subject and at a group level.

Construction of the PIS

The PIS was developed by a group of experts at Imperial College London after distilling observations of patient-reported insight across multiple psychedelic studies.

The PIS is a seven-item scale comprised of two components: a core psychological component (six items) and a supplementary behavioural component (one item). It can be used to assess changes in psychological insight following a psychedelic experience.

Online prospective studies: Study 1

Recruitment of participants occurred via online advertisements as well as through psychedelic retreat providers. Data were collected at various timepoints including baseline, post-experience, post-retreat, and endpoint 1 and endpoint 2 psychological outcomes.

Principal components analysis was performed on the PIS-6 to determine the interrelationships between individual items. The internal consistency of the questionnaire was assessed using Cronbach’s alpha.

Criterion validity was tested on the ceremony survey dataset using the MEQ, EBI and CEQ indicators of acute psychedelic effects, the PIS-6 indicator of psychological insight and the WEMWBS indicator of psychological well-being.

Following recommendations put forward by Kline (2015), several indicators of overall fit were reported, as well as direct and indirect effects mediated through psychological insight (PIS-6). Total effects were calculated by summing direct and indirect effects on well-being for MEQ, CEQ and EBI, respectively.

Concurrent validity was assessed between the psychological insight scale (PIS) and the well-being scale (WEMWBS) at timepoint T3.

In a subsample of individuals with low well-being, PIS-6 was a stronger predictor of changes in well-being than WEMWBS.

Study 2: External and convergent validation

To examine whether findings from a ceremony setting hold true in other settings, a second prospective online survey was conducted. This survey included insight-related psychometric scales and allowed verification of convergent validity.

In study 2, measures were completed 1-day post-experience, at the same time as acute measures (MEQ, EBI and CEQ). Spearman’s rank correlation analyses were used to assess predictive validity of the PIS and change in well-being after 2 weeks.

The SRIS is a 20 item scale with two subscales, Insight and Self-Reflection. The Insight subscale is positively correlated with psychological flexibility and negatively correlated with depression.

Due to the lack of scales assessing changes in insight with respect to an ‘event’/experience, the MIS from the validated TRS was used in isolation. The MIS is comprised of five items and scores on a 3-point Likert-type scale.

Data extraction and cleaning

All data were exported and prepared using MATLAB (release 2019b), and two incomplete responses were flagged for data quality reasons. These responses were recognised as valid.

Study 1: Ceremony Survey

Participants stated what drug(s) were taken during the ceremony. Psilocybin/magic mushrooms/truffles were the most common, followed by Ayahuasca and DMT.

A PCA was performed on the first six items from the PIS and revealed that 85.5% of the variance was shared between the variables. A total of 73.57% of the variance was explained by the first component.

The mean PIS-6 scores were highest 1 day following the experience, with slight decreases after 2 and 4 weeks. The mean PIS-7 scores were lowest at +1 day post-experience, increasing to the highest at 2 weeks, before lowering slightly at 4 weeks.

A path analysis was performed and a model was developed with near-perfect fit and RMSEA, CFI and SRMR values.

The model indicated that insight, challenging experiences, and mystical-type experiences had a moderate effect on well-being 2 weeks after the psychedelic retreat. The EBI had a significant indirect effect on well-being that was mediated by insight scores.

MEQ, CEQ, EBI and PIS-6 together accounted for 44% of variance in well-being at the 2-week endpoint, and 57% of the effect of EBI on well-being was mediated by insight.

Participants within the low well-being subgroup demonstrated a moderate to strong correlation between post-retreat PIS scores and change in well-being at 2 weeks.

Concurrent validity. Well-being changed 2 weeks post-retreat with both psychological insight and rating of reported behavioural changes.

Study 2: Global Psychedelic Survey

Participants and drug type. Data were included from 279 individuals who participated in the second survey (Global Psychedelic Survey), with a completion rate of 48.8%.

External validity

Confirming construct validity, psychological insight scores were extremely high internal reliability, and correlated strongly with behavioural changes at 2 weeks post-experience.

Descriptive statistics showed that the majority of participants gained insight at 1 day, 2 weeks, and 4 weeks following their psychedelic experience.

Post-acute insight was positively associated with change in well-being 2 weeks post-experience, and this relationship was stronger within the low well-being subgroup.

Concurrent validity. There was a moderate positive relationship between psychological insight and change in well-being 2 weeks post-experience, and a moderate correlation between reported positive behavioural changes influenced by psychological insight and change in well-being.

A multivariate regression model was constructed with psychological insight at 2 weeks post-experience as the target variable, and acute measures of emotional breakthrough, MEQ and CEQ as predictors.

Convergent validity was found between the PIS and SRIS-IN subscales at 4 weeks post-experience, but the correlation was small. The MIS demonstrated high convergence with the PIS at 1 day post-experience.


The present work sought to introduce and validate the PIS, a novel scale designed to measure personal psychological insight after a psychedelic experience. It also sought to demonstrate how the PIS may mediate long-term psychological effects.

The PIS appears to be a sensitive scale, yielding high and rangeful scores in both studies in which it was deployed. It demonstrated positive relationships with well-being at 2 weeks post-retreat and emotional breakthrough predicted insight at 2 weeks post-experience.

Results from study 2 confirm the initial findings and suggest that even in a non-specific setting, psychedelics maintain the capacity to facilitate psychological insight. There is some suggestion of a different temporal profile to PIS scores in study 1 and 2, but no formal analyses were applied in this regard.

In study 2, the convergent validity of the PIS was demonstrated by comparing scores with existing subjective measures of insight. The MIS showed highly convergent scores with those from the PIS, and can be used to measure insight referenced to non-psychedelic drug-induced experiences.

Insight and emotional breakthroughs

Psychodynamic therapy and modern, third-wave psychotherapies encourage emotional exploration and insight. Insight has been shown to promote more enduring, therapeutically beneficial effects from psychotherapy.

The EBI measures an individual’s ability to face emotionally difficult feelings and experience emotional breakthrough.

Hence, emotional breakthrough and psychological insight are interrelated, and the EBI refers to a dynamic, affective process occurring during a psychedelic experience, whereas the PIS indexes a more reflective, cognitive or epistemic processing taking place after the psychedelic experience.

A recently published paper explores the co-occurrence of acute insights and emotional breakthroughs by comparing the PIQ and EBI. The PIQ explores transpersonal or philosophical insights, whereas the EBI explores the overcoming of psychological resistance potentiating relief, breakthrough and/or resolution.

Psychological insight, as measured by the PIS, is positively associated with mental well-being. However, some previous work suggests that greater self-insight can be associated with greater depressive symptoms, particularly in individuals with negative self-perceptions.

Insight, mystical experiences and challenging experiences

Here, we found that the extent of psychedelic occasioned mystical experiences was not reliably predictive of psychological insight at +2 weeks across studies 1 and 2. Moreover, psychological insight did not significantly mediate the effect of mystical experiences on well-being.

The CEQ is a multifaceted scale that contains items that probe a range of psychological phenomena, including physical distress, grief, and psychotomimetic symptoms. The CEQ may explain why previous studies have reported mixed results for the relationship between challenging experiences and long-term psychological outcomes.

Insight and well-being

In line with evidence that insight is important in the psychotherapeutic process, insight was more strongly predictive of changes in well-being in a low well-being subgroup.

We found evidence to support the 1-2-1 relationship between psychological insight and improved well-being. Previous studies have shown that psychological insight is related to improved well-being and overall life satisfaction, and that psychedelic-induced insight is a key factor in the acute psychological effects that ultimately lead to a change in addictive behaviour. Psilocybin-assisted therapy for major depressive disorder is associated with greater self-awareness and insight into one’s maladaptive thought patterns, which may help explain why psilocybin has shown some preliminary signs of efficacy for patients with obsessive compulsive disorder.

Future studies may seek to assess the relationship between emotional breakthroughs and well-being in clinical populations, and may seek to use the PIS in relation to non-psychedelic events or processes to further assess its validity and usefulness.


The subjective nature of insight in psychedelic experiences should be taken into account when interpreting the present results. Moreover, future research should explore whether persisting delusions are being misinterpreted as insights.

This study utilised opportunistic sampling and therefore its populations were a mixture of psychologically healthy and unwell individuals. We ran subanalyses on a low well-being subgroup to assess potential differences in PIS scores.

The demographics of the study populations are as follows: 58% of participants were males and 78% were Caucasians. The majority of participants had prior psychedelic experience and expectancy scores could be entered as a covariate in future analyses to account for positive perspective bias.

Future studies should aim to minimise attrition rates and assess what factors are contributing to them. A controlled study with inactive or active drug controls would provide a better impression of the specificity of psychedelic-experience induced insight.

The present study did not include a formal measure of content validity, but a mixed methods approach would have been beneficial.

Increased well-being is a reliable psychological change following a psychedelic experience. It would be interesting to measure the relationship between insight and other psychological domains.

The present study highlights potential mental health benefits from psychedelic use, but it is important not to neglect anomalous cases where negative health outcomes have occurred after psychedelic use.


We have introduced a new scale, the PIS, to measure psychological insight emerging after a psychedelic experience. The PIS mediates the relationship between emotional breakthrough and subsequent improvements in psychological well-being.


Authors associated with this publication with profiles on Blossom

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.

Chris Timmermann
Chris Timmerman is a postdoc at Imperial College London. His research is mostly focussed on DMT.

Leor Roseman
Leor Roseman is a researcher at the Centre for Psychedelic Research, Imperial College London. His work focussed on psilocybin for depression, but is now related to peace-building through psychedelics.


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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