The 5D-ASC is a questionnaire that people complete after an altered state to rate what they experienced. It is the latest of a family of scales developed by Dittrich in German; an extended version of the earlier OAV, it was published in 1999 and contains 94 items (Studerus et al., 2010). Its dimensions include oceanic boundlessness, dread of ego dissolution, visionary restructuralization, auditory alterations and vigilance reduction (Studerus et al., 2010).
A 2010 evaluation pooled data from 43 experimental studies of psilocybin, ketamine and MDMA. It found that the original scales each mixed several things together, and built 11 narrower subscales with better measurement properties (Studerus et al., 2010). Swiss psilocybin studies have used the Altered States of Consciousness Rating Scale (Hasler et al., 2004).
Like other self-report scales, it captures how people remember and describe an experience, not what caused it. Scores can differ by setting, expectation and language, and they describe intensity and quality, not safety or benefit.
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