This article presents a taxonomy of altered states of consciousness, primarily based on their central phenomenological features. Following taxonomic principles and a modified Delphi methodology, a multidisciplinary, international group identified eight distinct phenomenological/behavioral states (some with subcategories): proto and transitional, delirium, minimal to no awareness, experiential...
The results of two studies suggest that the Phenomenology of Consciousness Inventory has adequate reliability and validity in assessing alterations in phenomenological experience associated with stimulus conditions, such as eyes open and closed, sitting quietly, and an hypnotic induction.