UCLA Loneliness Scale

The UCLA Loneliness Scale (Version 3) is a 20-item self-report measure developed by Daniel Russell to assess subjective feelings of loneliness and social isolation. Items cover feelings of connectedness, belonging, isolation, and being understood, rated on a 1–4 scale (never to always), with total scores from 20 to 80. It is the most widely used loneliness measure in psychological research. The UCLA Loneliness Scale is relevant to psychedelic research as loneliness and social disconnection are increasingly recognized as both risk factors for mental illness and potential treatment targets. Psychedelics, particularly MDMA and psilocybin, have been associated with increased feelings of social connectedness, and the UCLA Loneliness Scale can capture changes in perceived social isolation following psychedelic-assisted therapy. The scale has high internal consistency (α = 0.89–0.94) and convergent validity with other measures of loneliness and social support.