The Psychedelic Integration Scales: Tools for Measuring Psychedelic Integration Behaviors and Experiences

Whitney and colleagues situate their work in a context of renewed scientific and public interest in classic psychedelics (for example, psilocybin and LSD), noting that these substances can occasion profound and sometimes destabilising changes in consciousness. They observe that while many psychedelic experiences lead to lasting improvements in wellbeing, outcomes vary substantially depending on the context and aftercare, and that ‘‘psychedelic integration’’—the process by which a psychedelic experience translates into positive changes in daily life—remains underdefined and empirically under‑studied. The study sets out to create and provide initial validation evidence for two brief psychometric scales intended to measure distinct aspects of post‑acute integration: the Integration Engagement Scale (IES), capturing observable, behavioural engagement with integration practices, and the Experienced Integration Scale (EIS), capturing intrapsychic feelings of being integrated. The authors aimed to produce practically useful tools for research and applied settings by following an iterative scale‑development process involving expert input, cognitive interviewing, factor analyses, and assessments of reliability and convergent/divergent validity.

The researchers followed an Iterative Process Model of scale development across five sequential studies, combining qualitative item refinement with quantitative psychometric testing. Item pools were generated from a literature review, expert consultation, and first‑person accounts; the IES item pool began with 112 items and a complementary EIS pool with 149 items was later created. Study 1 (cognitive interviews) recruited a convenience sample of N = 13 adults known to the authors who had prior psychedelic experience; participants described their thought processes responding to IES items and the pool was revised based on feedback. Study 2 solicited item and definitional feedback from researchers and clinicians with psychedelic expertise (initially N = 10, later N = 13–14 for item ratings); experts rated item quality on a nine‑point scale and the proposed definition on a four‑point scale. Study 3 used a content validity index (CVI) procedure with four senior experts to rate item relevance and representativeness across pre‑specified subdomains (Reflection, Application, Settled, Harmonized, Improved); item‑level and scale‑level CVIs were computed. For quantitative scale structure and reliability, Study 4 administered filtered item sets to an M‑Turk sample of individuals who reported having used psychedelics (final N = 232 after attention checks). Exploratory factor analysis (EFA) was conducted using SPSS with Promax (oblique) rotation, guided by Scree plots, parallel analysis, and Minimum Average Partialing, and internal consistency was assessed with Cronbach's alpha. Study 5 collected a larger M‑Turk sample (recruitment target noted as N = 600, final analytic sample N = 315 after exclusions) to perform confirmatory factor analysis (CFA) in AMOS (reporting chi‑square, Comparative Fit Index (CFI) and Root Mean‑Square Error of Approximation (RMSEA)), and to assess convergent and divergent validity. Convergent validity used selected item subsets from the Persisting Effects Questionnaire (PEQ) and the Mystical Experience Questionnaire (MEQ), plus an Awe Scale (AWE‑S); divergent validity used the five‑item Satisfaction With Life Scale. All survey items used Likert response formats and participants were asked to consider their most recent psychedelic experience. Pacifica Graduate Institute Institutional Review Board approved the procedures.

Study 1 produced qualitative refinements to wording and content: 56 revisions were made to the initial pool of 112 IES items based on cognitive interview feedback that identified vague, double‑barrelled, or variably interpreted items. In Study 2, expert ratings led to a revised definition of integration—"The process by which a psychedelic experience translates into positive changes in daily life"—and to item quality metrics: the overall average expert quality score for the IES pool was 6.80 (between "Good" and "Great") and for the EIS pool 7.24 (between "Great" and "Excellent"). From these ratings, 31 IES items and 31 EIS items were retained for further evaluation after redundancy elimination. Study 3 (CVI with four senior experts) yielded high content validity: the IES achieved a scale‑level CVI (S‑CVI) of 0.96 and a representativeness index of 1.0; the EIS had S‑CVI 0.92 and representativeness index 1.0. Study 4 used an M‑Turk sample (N = 232) and, after filtering items based on I‑CVI thresholds and redundancy, retained 12 items for each scale. EFA with Promax rotation supported a unidimensional structure for both scales: the single factor for the IES explained 50.87% of variance (KMO = 0.932, Bartlett's p < 0.001) and the single factor for the EIS explained 56.13% of variance (KMO = 0.947, Bartlett's p < 0.001). Factor loadings were generally between 0.6 and 0.8 (two EIS items slightly higher). Internal consistency was excellent: Cronbach's alpha = 0.90 for the IES and 0.92 for the EIS. In Study 5 the CFA (final sample N = 315 after exclusions for non‑use, attention failures, or incoherent responses) tested 12‑item one‑factor models for each scale. Model fit was strong for both: IES CFI = 0.969 and RMSEA = 0.032 (90% CI 0–0.05), chi‑square = 71.0 with 54 degrees of freedom; EIS CFI = 0.958 and RMSEA = 0.037 (90% CI 0.014–0.054), chi‑square = 76.7 with 54 degrees of freedom. Convergent validity correlations were large: PEQ subset with IES r = 0.76 and EIS r = 0.73 (both p < 0.001); MEQ subset with IES r = 0.65 and EIS r = 0.73 (p < 0.001); AWE‑S with IES r = 0.66 and EIS r = 0.70 (p < 0.001). Divergent validity showed moderate correlations with Satisfaction With Life: IES r = 0.47 and EIS r = 0.42 (p < 0.001). The correlation between the two scales was r = 0.83 (p < 0.001). Average variance extracted (AVE) was 0.51 for the IES (square root 0.71) and 0.56 for the EIS (square root 0.75); the interscale correlation exceeding these values indicated a statistical lack of discriminant validity between the measures. Descriptive characteristics of the CFA sample included majority recent use of mushrooms (50.2%), followed by LSD, MDMA, DMT, ayahuasca and smaller proportions for other substances; time since last experience varied, with many participants reporting use within the past month or year.

Whitney and colleagues interpret their findings as supporting the initial validity and reliability of two brief scales measuring complementary facets of psychedelic integration: behavioural engagement (IES) and subjective experienced integration (EIS). Both scales demonstrated strong internal consistency, unidimensional factor structure in EFA and CFA, and robust convergent validity with related constructs (persisting positive effects, mystical experience elements, and awe). Moderate correlations with life satisfaction provided evidence consistent with divergent validity, though not complete independence. The authors acknowledge a notable overlap between the scales: a high interscale correlation (r = 0.83) exceeded the square root of AVE for either scale, indicating lack of discriminant validity in this sample. They propose plausible reasons reported in the paper: integration engagement may lead to experienced integration over time, and because many participants' last psychedelic use was not recent, scores on engagement and experience may have converged. The authors suggest discriminant validity might be better observed closer in time to an experience or among novice users for whom engagement and experienced integration may initially diverge. Several limitations are described. The convenience and M‑Turk samples are demographically and culturally limited (predominantly White, US‑based), restricting generalisability. Data were most relevant to classic psychedelics (mushrooms, LSD, MDMA, DMT, ayahuasca) and may not generalise to other substances or dosing contexts. The prior application of strict content validity and redundancy filters (a face‑value redundancy assessment) before EFA may have favoured a single‑factor solution and introduced selection bias. The use of item subsets from the PEQ and MEQ for convergent validity, chosen a priori on face value, may have influenced correlation magnitudes. The authors also note that all scale items are positively keyed and that single time‑point sum scores should be interpreted cautiously because optimal integration trajectories vary by dose, individual, and context. In terms of implications, the authors present the scales as practical tools to help clinicians and facilitators assess integration status and to inform integration support, harm reduction, and future research. They recommend collecting data in clinical trials to identify meaningful cut‑offs and suggest an administration strategy (for example, EIS within 48 hours followed by weekly EIS and IES for 8–12 weeks) while emphasising that scores should be tracked over time. The discussion also situates integration practices beyond therapy—highlighting nature, community, seasoned guides, and contemplative practices—and stresses ethical responsibilities around indigenous knowledge and ceremonial traditions in ongoing psychedelic work.

The authors conclude that the Psychedelic Integration Scales represent a step toward more responsible and beneficial use of psychedelics by providing brief, face‑valid instruments to assess post‑acute integration. They anticipate that greater emphasis on measurement and support for integration will increase the likelihood that psychedelic experiences translate into sustained, beneficial changes in daily life.