5D-ASC

The Five Dimensions of Altered States of Consciousness (5D-ASC) is a 94-item self-report questionnaire using visual analog scales (0–100mm) to assess the subjective effects of altered states of consciousness. Developed by Adolf Dittrich and later refined by Erich Studerus and Felix Hasler, it measures five primary dimensions: Oceanic Boundlessness (OBN, related to mystical/positive experiences and derealization), Anxious Ego Dissolution (AED, related to anxiety and loss of control), Visionary Restructuralization (VRS, related to visual hallucinations and synesthesia), Auditory Alterations (AA), and Reduction of Vigilance (RV). The 5D-ASC is the most comprehensive standardized measure of acute psychedelic effects and is used extensively in European psychedelic research (University of Zurich, Imperial College London, Maastricht University). Subscale profiles can distinguish between different psychedelic compounds and doses, making it valuable for pharmacological characterization studies.