[Animal models of psychiatric disorder and their validity--from the perspective of behavioral pharmacology].

Animal models of psychiatric disorders are indispensable tools to gain insights into neural mechanisms underlying these disorders and to assess potential therapeutic actions of novel compounds in preclinical settings. However, it is difficult to establish appropriate animal models for these disorders because there is no proof on whether or not what occurs in the animal brain is comparable to what occurs in the human brain. The initial development of animal models of psychiatric disorders is often based on "face validity" as reflected in the similarity of behavioral signs and symptoms observed in humans and animal and subsequently based on "construct validity" as measured by strong correlation in behaviors and neural events between the animal model and patients of the disorder. The practical value of such animal models is reflected ultimately in their "predictive validity" in predicting the therapeutic efficacy of new treatments for psychiatric disorders. The present review will focus on animal models of schizophrenia and depression by the use of mainly environmental stress and pharmacological treatments, which are expected to induce signs and symptoms analogous to those of patients with such disorders.