Using data from more than 21,800 adults in two UK birth cohorts, researchers found that lifetime psilocybin and LSD use was associated with stronger pro-environmental attitudes and a greater likelihood of following a vegetarian diet, with psilocybin showing the clearer dietary pattern. Mediation analyses suggested that environmental attitudes statistically accounted for the psilocybin-vegetarianism association and part of the association with lower red meat consumption, but the observational design cannot establish causation.