Progress in the treatment of severe psychiatric disorders has been slow, despite tremendous advances in neuroscience. In other fields of medicine, the prognosis of many previously devastating disorders has improved thanks to new treatments that were developed based on biological insights gained in animal models. In breast cancer, for example, the study of estrogen receptors in tumors growing in rodents paved the way to novel hormonal therapies. Modeling disease in animals starts with a hypothesized biological dysfunction (eg, uncontrolled cell proliferation) that is inducible by experimental manipulations (eg, carcinogen exposure) and results in quantifiable manifestations (eg, tumor growth). Psychiatric disorders, however, have been challenging to model in animals.