In a survey of 1,993 people who recalled their worst 'bad trip' after taking psilocybin mushrooms, 39% ranked it among the top five most challenging experiences of their lives. Eleven percent put themselves or others at risk of physical harm, with factors such as higher dose, longer duration, and lack of physical comfort or social support increasing that risk. About 2.6% acted aggressively and 2.7% needed medical help. Among those whose experience was more than a year prior, 7.6% sought treatment for lasting psychological symptoms, with three cases linked to enduring psychotic symptoms and three to attempted suicide. Despite difficulties, 84% reported benefiting from the experience. The incidence of risky behavior or lasting distress is very low when psilocybin is given in controlled laboratory settings.
A questionnaire was developed and validated to measure challenging psychological reactions to the hallucinogen psilocybin, often called 'bad trips.' Seven factors emerged: grief, fear, death, insanity, isolation, physical distress, and paranoia. These factors were linked to how difficult, meaningful, spiritually significant, and impactful on well-being participants rated their experiences. The factor structure was consistent regardless of gender or prior struggles with anxiety or depression. The questionnaire offers a tool for studying predictors and outcomes of such challenging experiences.