The 3D-ASCr scale: A revalidation of the core dimensions of the Altered States of Consciousness Rating Scale 5D(11)-ASC for psychedelic research.

A psychometric revalidation of the Altered States of Consciousness Scale (ASC) using data from 901 questionnaires across 16 psychedelic studies (with LSD, psilocybin, mescaline, and DMT) shows that ten of the eleven subscales can be grouped into three higher-order dimensions—Positive Effects, Distressing Effects, and Perceptual Effects—mirroring the original three-dimensional model but with improved statistical fit. The Anxiety subscale could not be integrated due to floor effects (low anxiety in the sample) but is retained for clinical relevance. The revised scale, 3D-ASCr, is recommended for use with classic serotonergic psychedelics.

Study at a glance

Abstract

The Altered States of Consciousness Scale (3/5D-ASC or 11-ASC) is widely used to assess non-ordinary states of consciousness, particularly for psychedelic research. However, its original dimensional model (3D-ASC within 5D-ASC) and later 11-subscale structure (11-ASC) have a hierarchically incompatible higher/lower-order structure. Although the 11-ASC offers superior model fit, the 3D-ASC remains widely used for summarizing broader experiential domains. We wanted to provide an updated, psychometrically revalidated version of the ASC. We tested whether the 42-item 11-ASC could be integrated into a coherent three-dimensional framework. We further hypothesized that this revised model would outperform the original 66-item 3D-ASC while preserving its conceptual clarity. Data from 901 5D-ASC questionnaires from 398 healthy participants across 16 randomized, mostly placebo-controlled psychedelic (lysergic acid diethylamide, psilocybin, mescaline, and N,N-dimethyltryptamine) studies were split for exploratory and confirmatory factor analysis. We compared the 3D-ASC and 11-ASC in terms of reliability and model fit, and tested whether the 11-ASC could be summarized within a three-dimensional model. Ten of the 11 subscales formed three higher-order dimensions-Positive (PosE), Distressing (DisE), and Perceptual (PerE) effects-mirroring the 3D-ASC but with improved fit. We propose this as the 3D-ASCr scale. The Anxiety subscale could not be integrated due to consistent floor effects (low anxiety in the sample), but given its clinical relevance, it is retained within 3D-ASCr (as part of DisE or a standalone subscale). The 3D-ASCr is an updated version of the ASC and is recommended for use with classic serotonergic psychedelics in both clinical practice and research.