Chapter 5 reviews background information concerning schizophrenia as well as prevalence, developmental, and comorbidity, and multicultural findings. Various etiologic theories are discussed. An overview of genetic principles is provided prior to an in-depth discussion of heritability, family, twin, and genetic linkage findings. Specific candidate genes are reviewed along with results from genome wide association studies. Structural studies are discussed along with molecular and functional studies. The chapter delves into the role of dopamine as well as other neurotransmitters in the disorder. Pharmacological interventions are discussed, including the mode of action of typical and atypical antipsychotic medications. Information pertaining to augmentation and use of experimental interventions in the treatment of schizophrenia is also discussed.