This observational, naturalistic study (n=1000), conducted by the Psychedelic Data Society (with the Quantified Citizen app), is set to explore the relationship between substance use and personality profiles.
This retrospective, case‑control observational study will survey adults worldwide via a mobile app to assess associations between histories of recreational or therapeutic substance use and current personality profiles.
Personality will be measured using the Big Five Inventory‑44 (BFI) and perceived retrospective changes via a self‑constructed Retrospective Personality Scale (RPS); substance use history is self‑reported and participants will be assigned to exposure groups (psychedelics, stimulants, depressants, cannabinoids, mixed, or substance‑naive).
The remote, anonymous design aims to increase accessibility and diversity; personalised result summaries will be shared with participants for transparency and engagement.
Participants reporting past use of classical and non-classical psychedelics.
Self-reported past use of psychedelics (psilocybin, LSD, mescaline, DMT, ayahuasca, 5‑MeO‑DMT, ibogaine, salvia, phenethylamines).
Participants reporting past use of stimulant drugs only.
Self-reported past use of stimulants (cocaine, crack, amphetamines, methamphetamines, prescription stimulants).
Participants reporting past use of depressant drugs only.
Self-reported past use of depressants (benzodiazepines, opiates, prescription opioids).
Participants reporting past use of cannabinoid compounds only.
Self-reported past use of cannabinoids (THC, CBD, medical cannabis).
Participants reporting past use of both psychedelic and non-psychedelic substances.
Self-reported past use of combinations of psychedelics and non-psychedelic drugs (e.g., MDMA, ketamine, stimulants, opioids, benzodiazepines, cannabis).
Participants reporting no past use of listed substances (excluding alcohol and nicotine).
Self-reported absence of past use of study-listed substances (selected 'None of the above').