The common classifications for hallucinogens are psychedelics, dissociatives and deliriants. Serotonergic psychedelics like psilocybin, LSD, and mescaline act as 5-HT receptor agonists. Examples of classical psychedelics include DMT, LSD and psilocybin. Mescaline causes cross-tolerance with other serotonergic psychedelics such as LSD and psilocybin. The tryptamine psychedelics, such as DMT and psilocybin, structurally resemble serotonin itself. The term is most commonly associated with hallucinogens, particularly psychedelics and entactogens. The effects described are similar to those of indole tryptamine psychedelics. His work primarily focused on the effects of psychedelics, primarily LSD. A decade later, he began experimenting with psychedelics, including LSD, often while floating in isolation. Leary continued to take drugs frequently in private, but stayed away from proselytizing psychedelics. This is substantially different from serotonergic psychedelics, with which brainwave patterns generally show a desynchronization. The episodes explore topics including memory, dreams, anxiety, mindfulness, and psychedelics. Some people report closed-eye hallucinations under the influence of psychedelics. They were hip to psychedelics as psychiatric medicine. This is a notable departure from the effects of serotonergic psychedelics.