Abstract
Acute adverse psychological reactions to classic hallucinogens (“bad trips”, or “challenging experiences”), while usually benign with proper screening, preparation, and support in controlled settings, remain a safety concern in uncontrolled settings (such as illicit use contexts). Anecdotal and case reports suggest potential adverse acute symptoms including affective (panic, depressed mood), cognitive (confusion, feelings of losing sanity), and somatic (nausea, heart palpitation) symptoms. Responses to items from several hallucinogen-sensitive questionnaires (Hallucinogen Rating Scale, the States of Consciousness Questionnaire, and the 5-Dimensional Altered States of Consciousness questionnaire) in an internet survey of challenging experiences with the classic hallucinogen psilocybin were used to construct and validate a Challenging Experience Questionnaire (CEQ). The stand-alone CEQ was then validated in a separate sample. Seven CEQ factors (grief, fear, death, insanity, isolation, physical distress, and paranoia) provide a phenomenological profile of challenging aspects of experiences with psilocybin. Factor scores were associated with the difficulty, meaningfulness, spiritual significance, and change in well-being attributed to the challenging experiences. The factor structure did not differ based on gender or prior struggle with anxiety or depression. The CEQ provides a basis for future investigation of predictors and outcomes of challenging experiences with psilocybin, and should be explored as a measure of challenging experiences with the broad class of classic hallucinogens.