Dopaminergic pathways involving the neurotransmitter dopamine are of general importance in the human brain where they are involved in various forms of cognitive, motor, and hormonal control. Putative abnormalities in the function of these pathways have formed the basis of what is termed the dopamine hypothesis of schizophrenia, or DHS, the focus of this entry. In approximately the last quarter of the 20th century (e.g., ∼1975–2000), the DHS was arguably the most prominent etiologic theory in psychiatry, widely discussed, taught to all medical students and psychiatric residents, and routinely reviewed in major textbooks.