A mood disorder characterized by profound sadness, fatigue, altered sleep and appetite, as well as feelings of guilt or low self-worth. Depression is often accompanied by perturbations in metabolic, hormonal, and immune function. A critical element in the pathophysiology of depression is inflammation. As a result, elevated biomarkers of inflammation, including the proinflammatory cytokines interleukin-6 and tumor necrosis factor-alpha, are commonly observed in depressed people. Although selective serotonin reuptake inhibitors and cognitive behavioral therapy typically form the first line of treatment for people who have depression, several non-pharmacological adjunct therapies have demonstrated effectiveness in modulating depressive symptoms, including exercise, dietary modification (especially interventions that capitalize on circadian rhythms), meditation, sauna use, and light therapy, among others.

A naturally occurring psychedelic compound produced by more than 200 species of mushrooms. As a prodrug, psilocybin is quickly converted by the body to psilocin, which has mind-altering effects including euphoria, visual and mental hallucinations, changes in perception, a distorted sense of time, and spiritual experiences, and can include possible adverse reactions such as nausea and panic attacks.

A class of hallucinogenic substances whose primary action is to alter cognition and perception, typically as serotonin receptor agonists, causing thought and visual/auditory changes, and "heightened state of consciousness." Major psychedelic drugs include mescaline, LSD, psilocybin, and DMT. Psychedelics have a long history of traditional use in medicine and religion, for their perceived ability to promote physical and mental healing.