The natural significance of its widespread presence remains undetermined. Structurally , DMT is analogous to the neurotransmitter serotonin (5-HT), the hormone melatonin , and other psychedelic tryptamines, such as 5-MeO-DMT , bufotenin , and psilocin (the active metabolite of psilocybin ). In some cultures DMT is ingested as a psychedelic drug