Modeling schizophrenia in animals represents a formidable challenge because the most characteristic symptoms of this disorder, auditory hallucinations and delusional beliefs, cannot be directly modeled in animals. Furthermore, limited current understanding of the etiology and pathophysiology underlying the clinical features of this disorder greatly hinders the ability to develop valid models based on those aspects. To circumvent these issues, investigators have attempted to recreate the leading candidate biochemical, neuroanatomical, and genetic abnormalities for this disorder in animals using pharmacological, developmental, neurotoxic, genetic engineering, and other methods. The validity of these animal preparations as animal models for schizophrenia is generally based upon the extent to which they induce measurable behavioral changes that are homologous or analogous to the core clinical features or the information-processing endophenotypes (presymptom phenotypes) that are seen in schizophrenia. The utility of any animal model to serve as a screen for novel treatments is considered related to the extent to which the schizophrenia-relevant behaviors it exhibits can be ameliorated by drugs with known efficacy in schizophrenia but not by drugs known to be therapeutic for brain disorders other than schizophrenia.