WHO-5

The WHO-5 Well-Being Index is a short, positively worded 5-item self-report measure of current mental well-being developed by the World Health Organization Regional Office for Europe. Items cover cheerfulness, calm/relaxation, active/vigorous feelings, waking up refreshed, and daily interest. Each item is rated 0–5 over the past two weeks, with raw scores (0–25) multiplied by 4 to yield a percentage scale (0–100). A score below 28 suggests possible depression and warrants further assessment. The WHO-5 is valued in psychedelic research for its focus on positive psychological states rather than symptom reduction, complementing deficit-focused measures like the PHQ-9 or MADRS. It is among the most widely used well-being measures globally, translated into over 30 languages, and is free for use. Its sensitivity to change makes it suitable for detecting improvements in subjective well-being following psychedelic-assisted therapy.