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

Research into psychedelic-assisted change has increasingly suggested that the acute subjective features of a psychedelic experience—particularly peak or emotional breakthrough experiences—may mediate enduring psychological benefits. Prior studies have linked self-reported insight during or after psychedelic sessions to reductions in depressive symptoms and to changes in addictive behaviours, and measures such as the Mystical Experience Questionnaire (MEQ), the Emotional Breakthrough Inventory (EBI) and the Challenging Experience Questionnaire (CEQ) have been used to capture related acute phenomena. However, the investigators note a gap: existing insight measures are either trait-focused or designed to capture insight during the acute session rather than insight that crystallises in the days and weeks after an experience (the so-called subacute or ‘‘afterglow’’ period). Peill and colleagues therefore developed the Psychological Insight Scale (PIS), a seven-item instrument with a six-item core (PIS-6) assessing personal psychological insight emerging after an experience and a separate behavioural item (PIS item 7) to capture consequent positive changes in behaviour. The study aimed to validate the PIS psychometrically, testing factor structure and internal reliability, and to establish criterion (predictive and postdictive), concurrent and convergent validity across two prospective online samples: a ceremony/retreat cohort and a broader global psychedelic survey. Key hypotheses were that early post-acute PIS scores would predict improved well-being at 2 weeks, that PIS scores would correlate with contemporaneous well-being, that acute measures (EBI, MEQ, CEQ) would predict later PIS scores, and that PIS would converge with existing insight measures (MIS and SRIS-IN).

The validation used two prospective online studies. Study 1 (the ceremony survey) recruited participants planning to attend psychedelic retreats via online adverts and collaborating retreat providers; data were collected at multiple timepoints: baseline (T1, two weeks pre-ceremony), +1 day after a ceremony (T2), +1 day after the end of the retreat (T3), and follow-ups at 2 and 4 weeks post-retreat (T4 and T5). Study 2 (the global psychedelic survey) enrolled individuals reporting a single psychedelic experience in diverse contexts and collected measures anchored to that single event, with PIS and acute measures completed 1 day post-experience and follow-ups at 2 and 4 weeks. The PIS comprises six core items (PIS-6) scored on visual analogue scales (VAS) capturing novel personal insights about self, past events and desired change, plus a seventh behavioural item assessing self-reported behavioural changes motivated by insight; PIS-6 and item 7 were analysed separately. Acute experience measures included the EBI (emotional breakthrough, VAS 0–100), the revised 30-item MEQ (mystical-type experience), and the 26-item CEQ (challenging experiences). Well‑being was measured with the 14-item Warwick–Edinburgh Mental Well‑Being Scale (WEMWBS). Convergent validity in study 2 was assessed against the SRIS Insight subscale (SRIS-IN, trait insight) and the Mastery of Insight Scale (MIS) from the Therapeutic-Realizations Scale. Analyses included principal components analysis (PCA) of PIS-6 (with KMO and Bartlett's tests to assess suitability), Cronbach's alpha for internal consistency, Spearman correlations for concurrent and predictive validity (including subgroup analyses for low baseline well-being defined as WEMWBS ≤ 43), path analysis to test relationships among acute measures, PIS and 2-week well-being (reporting χ2, RMSEA, CFI, SRMR), and a multiple linear regression in study 2 predicting PIS from acute EBI, MEQ and CEQ. Missing or incomplete responses were removed during data cleaning; statistical software used included SPSS and GraphPad. The studies were observational and approved by an institutional ethics committee; participants provided informed consent and drug use was self-initiated and uncontrolled.

Sample sizes and context: Study 1 included 886 participants (61.6% questionnaire completion rate) drawn largely from retreat settings where 74% reported psilocybin use and 14% ayahuasca; Study 2 included 279 participants (48.8% completion) reporting a range of drugs (psilocybin 45%, LSD 41%, others including DMT, ketamine). Many participants had prior psychedelic experience (≈60% in study 1, 81% in study 2) and a proportion reported lifetime psychiatric diagnoses (280/886 in study 1; 91/279 in study 2). Factor structure and reliability: PCA of the six PIS items yielded a unifactorial structure. In study 1 the KMO = 0.855 and Bartlett's test χ2 = 1513.2, p < 0.001; the first component had an eigenvalue of 4.4 and explained 73.57% of variance, with the next component explaining <8.3%. Internal consistency was excellent across timepoints (Cronbach's α ≈ 0.93–0.95 in study 1 and α = 0.95 in study 2). Descriptive scores: In study 1, PIS-6 means were highest at +1 day (mean = 63.8, SD = 27.9), then 2 weeks (mean = 61.6) and 4 weeks (mean = 57.5); behavioural item 7 mean rose slightly by 2 weeks. In study 2, PIS-6 means were 47.7 (1 day), 56.3 (2 weeks) and 54.3 (4 weeks), with a similar temporal pattern for item 7. Predictive and concurrent validity (study 1): Path analysis (n = 283) showed excellent model fit (χ2 = 0.18, df = 1, p = 0.67; RMSEA = 0; CFI = 1.0; SRMR = 0.005). Standardised effects to well-being at 2 weeks included PIS (β = 0.22, p < 0.001), MEQ (β = 0.24, p < 0.001) and CEQ (β = -0.12, p < 0.05). Emotional breakthrough (EBI) exerted a strong effect on post-acute PIS (β = 0.58, p < 0.001) and an indirect effect on well-being mediated by PIS (indirect β = 0.13, B = 0.006, bootstrap 95% CI (0.003, 0.010), p < 0.001). Together baseline well-being, MEQ, CEQ, EBI and PIS-6 explained ≈44% of variance in 2-week well-being; MEQ, CEQ and EBI accounted for 42% of variance in PIS-6. Mediation estimates indicated that 57% of EBI's total effect on well-being was mediated via insight, whereas only 8% of MEQ's effect was indirect through PIS. Correlation results: In study 1, PIS (+1 day) correlated with change in well-being at 2 weeks (ΔWEMWBS) with rs = 0.344 (p < 0.001, n = 312); the low well-being subgroup showed a stronger correlation (rs = 0.506, p < 0.001, n = 120). Concurrent correlations (PIS at 2 weeks with ΔWEMWBS) were moderate: rs = 0.434 (p < 0.001, n = 416) for PIS-6 and rs = 0.415 (p < 0.001, n = 392) for behavioural item 7. Study 2 replication and external validity: PIS-6 again showed very high internal reliability (α = 0.95). Post-acute PIS (+1 day) predicted change in well-being at 2 weeks (rs = 0.248, p < 0.001, n = 190), with a stronger association in the low well-being subgroup (rs = 0.515, p < 0.001, n = 69). Concurrent correlations at 2 weeks were rs = 0.271 (p < 0.001, n = 198) for PIS-6 and rs = 0.316 (p < 0.001, n = 198) for item 7. Multiple regression predicting PIS at 2 weeks from acute measures explained ≈40% of variance (adjusted R2 = 0.405, F(3,101) = 24.63, p < 0.001); EBI (β = 0.473, p < 0.001) and MEQ (β = 0.270, p = 0.007) were significant predictors; the reported CEQ coefficient in the extracted text was β = -0.85 with p = 0.300, which the authors interpret as non-significant but the magnitude in the extraction appears inconsistent and may reflect an extraction artefact. Convergent validity: PIS-6 correlated strongly with the MIS at +1 day (rs = 0.797, p < 0.001, n = 266), indicating high convergence with a session‑referenced measure of insight. Correlation with the trait-focused SRIS-IN at 4 weeks was small but significant (rs = 0.180, p = 0.008, n = 182), suggesting partial and weaker overlap with trait insight measures.

Peill and colleagues conclude that the PIS is a sensitive, reliable unidimensional measure of personal psychological insight that typically emerges after a psychedelic experience, and that it performs well across two distinct prospective samples. They highlight that PIS-6 showed excellent internal consistency, a clear unifactorial structure, and both predictive and concurrent validity with change in well-being, particularly among participants with low baseline well-being. The study team report that emotional breakthrough during the acute experience was the strongest predictor of later psychological insight and that PIS scores mediated a substantial portion of the association between emotional breakthrough and improved well-being at 2 weeks. The authors situate these findings against existing insight measures, noting strong convergence between PIS and the MIS (an event-referenced psychotherapy scale) but only weak convergence with the SRIS-IN (a trait measure), which supports the PIS's focus on experience-referenced insight rather than trait self‑reflection. They further discuss conceptual distinctions between personal psychological insight (the PIS focus) and transpersonal or philosophical insight captured by measures such as the MEQ, which may explain why mystical experiences were not consistently predictive of PIS scores across both studies. Likewise, the CEQ's multifaceted nature may underlie the inconsistent relationships between challenging experiences and insight or well‑being. Key limitations acknowledged by the investigators include the subjective and retrospective nature of self-reported insight, opportunistic sampling with mixed psychological health status, demographic imbalances (for example, a predominance of male and Caucasian respondents in study 2), high rates of prior psychedelic experience and potential expectancy biases, substantial attrition, and the observational design that precludes verification of dose, timing and drug type. The authors also note they did not perform a formal content‑validity index for the scale and that the PIS does not assess the emotional valence or objective accuracy of reported insights. They recommend future controlled studies (including placebo/active controls), analyses in clinical cohorts, exploration of drug-specific effects, formal content validation and mixed‑methods approaches, and investigation of rare adverse or anomalous responses including persistent delusional beliefs that might be misreported as insight. Finally, the authors propose that the validated PIS may prove useful beyond psychedelic research—for instance, to study insight following psychotherapy, major life events or other interventions—and that it opens opportunities to probe the neurobiology of insight by pairing the scale with neuroimaging and experimental designs.

The authors introduced and validated the Psychological Insight Scale, showing it to be a reliable and psychometrically coherent measure of personal psychological insight emerging after an experience. Across two prospective datasets the PIS demonstrated strong internal consistency, a unifactorial structure, predictive and concurrent relationships with improvements in well-being—especially in individuals with low baseline well-being—and high convergence with an event‑referenced measure of insight (MIS). The investigators conclude that psychological insight, as captured by the PIS, is an important mediator of the link between emotional breakthrough during a psychedelic experience and subsequent improvements in psychological well‑being, and that the PIS can facilitate further research into insight-related processes and their neurobiology.