Validation of the imperial psychedelic predictor scale.
Michael Angyus, Sarah Osborn, Eline Haijen, David Erritzøe, Joseph Peill, Taylor Lyons, Hannes Kettner, Robin Carhart-Harris
Psychol Med September 27, 2024 DOI: 10.1017/s0033291724002204 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Validation study Peer reviewed |
|---|---|
| Sample size | 1,635 |
| Population | Adults completing online surveys of naturalistic psychedelic use (N=741 and N=836) and participants in controlled administration studies (N=30 and N=28) |
| Topics | Altered states of consciousness Ego dissolution |
| Keywords | Psychedelic research Psychedelics Psychedelic studies Entheogens Hallucinogens Consciousness research Psychological assessment Psychometric scales Assessment tools Measurement tools Subjective experience measurement Survey instruments Psychometrics Subjective effects prediction Predictive modeling Outcome prediction Anticipation Forecasting Psychedelic response Individual differences Mystical experiences Spiritual experiences Challenging trips Peak experiences Altered perception Transformative experiences |
| Citations | 10 |
| Key points | The 9-item IPPS, measuring set, rapport, and intention, significantly predicts mystical, challenging, and emotional breakthrough experiences, with set and rapport accounting for 40% of variance in mystical experience in one controlled dataset. |
Abstract
Abstract Background Access to psychedelic drugs is liberalizing, yet responses are highly unpredictable. It is therefore imperative that we improve our ability to predict the nature of the acute psychedelic experience to improve safety and optimize potential therapeutic outcomes. This study sought to validate the ‘Imperial Psychedelic Predictor Scale’ (IPPS), a short, widely applicable, prospective measure intended to be predictive of salient dimensions of the psychedelic experience.
Methods: Using four independent datasets in which the IPPS was completed prospectively – two online surveys of ‘naturalistic’ use ( N = 741, N = 836) and two controlled administration datasets ( N = 30, N = 28) – we conducted factor analysis, regression, and correlation analyses to assess the construct, predictive, and convergent validity of the IPPS.
Results: Our approach produced a 9-item scale with good internal consistency (Cronbach's α = 0.8) containing three factors: set, rapport, and intention. The IPPS was significantly predictive of ‘mystical’, ‘challenging’, and ‘emotional breakthrough’ experiences. In a controlled administration dataset ( N = 28), multiple regression found set and rapport explaining 40% of variance in mystical experience, and simple regression found set explained 16% of variance in challenging experience. In another ( N = 30), rapport was related to emotional breakthrough explaining 9% of variance.
Conclusions: Together, these data suggest that the IPPS is predictive of relevant acute features of the psychedelic experience in a broad range of contexts. We hope that this brief 9-item scale will be widely adopted for improved knowledge of psychedelic preparedness in controlled settings and beyond.