Animal Models and Endophenotypes of Anxiety and Stress Disorders

An important criterion for developing animal models to study psychopathology involves establishing the validity of the model as a true representation of the process being studied. Generally, three types of validity are applied to animal models: face validity, construct validity, and predictive validity (1–3). Face validity refers to the outward similarity in appearance between the model and the illness. Construct validity, on the other hand, does not exclusively involve outward tangible signs of the modeled illness. Rather, it refers to the internal mechanism or state that underlies the illness. Finally, predictive validity refers to the ability of the animal model to identify therapeutic treatments for the illness. It should be noted that the different types of validity can be independent of each other; an animal model can possess predictive and construct validity without possessing face validity. Ideally, an animal model should possess both construct and predictive validity so that it may be used to understand the mechanisms and etiology of the disorder and also to identify promising treatments for the disorder.