Characterizing Psychedelic-Evoked Familiarity: A Comparative Study with Autobiographical and Déjà Vu Experiences.

Psychedelic experiences often evoke a sense of familiarity, an experiential quality that has received little empirical attention despite its potential therapeutic and cognitive significance. This study examined psychedelic-evoked familiarity in comparison to non-drug-induced forms of familiarity, including autobiographical and déjà vu experiences. An anonymous online survey was administered to 1050 participants, who completed the Sense of Familiarity Questionnaire (SOFQ) and psycho-emotional ratings for at least one of three experiences: Psychedelic, Autobiographical, or Déjà Vu. Across all SOFQ items, Psychedelic experiences were rated significantly higher in familiarity, particularly within the "Familiarity with Transcendent Features" category. Psychedelic experiences were also associated with greater emotional intensity, novelty, and comfort, with no increased anxiety, relative to the other experience types. Classic psychedelics generally elicited strong familiarity, while psycho-emotional responses varied across psychedelic types. Most participants described the familiarity as authentic and positively impactful, and approximately half reported enduring effects such as emotional transformation, interconnectedness, and reduced fear of death. These findings suggest that psychedelic-evoked familiarity is phenomenologically different from autobiographical and déjà vu familiarity. Psychedelic-evoked familiarity warrants further investigation to determine whether it serves as a phenomenological driver of the enduring psychological and existential benefits associated with psychedelic experiences.