Psilocybin (0.2 mg/kg) increased glucose metabolism in right frontotemporal cortical regions, especially the anterior cingulate, and decreased metabolism in the thalamus. Both MDE (2 mg/kg) and methamphetamine (0.2-0.4 mg/kg) caused cortical hypometabolism and cerebellar hypermetabolism. Cognitive activation-related increases in left frontocortical regions were attenuated under all three substances, but less so under MDE. The psilocybin results align with studies of acute schizophrenia showing frontal overactivity at rest but diminished capacity to activate prefrontal regions during cognitive tasks. The MDE findings support the idea that entactogens form a distinct psychoactive class intermediate between stimulants and hallucinogens.
People with endogenous psychoses (e.g., schizophrenia) often experience altered states of consciousness that resemble those induced by hallucinogenic drugs. In a study of 93 patients shortly after an acute psychotic episode, 50 healthy controls, and 7 patients with drug-induced psychosis, standardized questionnaires revealed that psychotic patients scored significantly higher than controls on measures of altered states. Over half of the endogenous patients endorsed 26% of items on one scale and 43% on another. Scores related to oceanic boundlessness (a pleasant, ego-dissolving experience) correlated with thought disturbance. The findings suggest that hallucinogen-like experiences, including pleasant ones, are common in acute psychosis and may be clinically overlooked.