[Animal models of psychiatric diseases: possibilities, limitations, examples and demonstration of use]

Animal models of psychopathology serve as a central tool for psychopharmacologists in their attempts to develop new, more efficient medications for psychiatric disorders, and in the efforts to explore the mechanisms of conventional and novel drugs. The development of efficient models for psychiatric diseases is complicated since the mechanisms of the disorders are not clear, major parts of the diagnosis depend on verbal communication with the patient and many of the symptoms are expressed mainly through the subjective experiences of the afflicted individual. Inspite of these difficulties, effective models were developed for most psychiatric diseases. The development of such models is based on their validation in three different dimensions: face validity--behavioral similarities between the model and the disorder; construct validity--similarities between the mechanisms related to the model and a mechanistic theory of the disease; predictive validity--that the model response to the conventional medications that are effective in the disease and will not respond to drugs that are not effective in the disease. The present paper presents three known models of depression; each induced in a different way and therefore represents a group of models: Reserpine-induced hypoactivity--represents the group of pharmacologically induced models. Forced swim test--represents the group of behaviorally induced models. Flinders Sensitive Line--represents the group of genetically induced models. The use of these models in an attempt to examine the range of action of a new potential antidepressant and its mechanisms of action is demonstrated with a recent set of experiments with inositol.