Moghaddam B: Animal models relevant to schizophrenia disorders. In Neuropsychopharmacology: The Fifth Generation of Progress. Edited by

Animal models used to study schizophrenia include both models of the full syndrome and models of specific signs or symptoms. As reviewed elsewhere (1), models are com-monly explored initially because of indications of so-called face validity, but they are evaluated scientifically in terms of their construct and etiologic and predictive validity with respect to both clinical phenomena and responsiveness to antipsychotic drugs. Here, models are organized by the ma-nipulations used to mimic the clinical phenomena. Thus, in some of these models, only specific dependent measures are utilized, whereas others are evaluated by using a range of dependent measures. A model is defined as any experimental preparation de-veloped to study a particular condition or phenomenon in the same or different species. Typically, models are animal preparations that attempt to mimic a human condition, in our case the human psychopathology associated with the group of schizophrenia disorders. In developing and assess-ing an animal model, it is important to specify the purpose intended for the model because the intended purpose deter-mines the criteria that the model must satisfy to establish its validity. At one extreme, one can attempt to develop an animal model that mimics the schizophrenia syndrome in its entirety. In the early years of psychopharmacology, the term animal model often denoted such an attempt to repro-duce a psychiatric disorder in a laboratory animal. Unfortu-nately, the group of schizophrenia disorders is characterized by considerable heterogeneity and a complex clinical course that reflects many factors that cannot be reproduced readily in animals. Thus, the frequent attempts to model the syn-dromes of schizophrenia in animals usually met with failure and so prompted skepticism regarding this entire approach. At the other extreme, a more limited use of an animal model related to schizophrenia is to study systematically th