Stress and Depression: Insights from Animal Models

The largest group of animal models of depression comprises procedures in which stress causes antidepressant-reversible behavioural abnormalities. Two models that have been extensively investigated are learned helplessness and a more recently developed paradigm in which anhedonia is induced by exposure to chronic mild stress. The problem of validating animal models is discussed, and several applications of animal models of depression are described, with particular reference to the chronic mild stress procedure. Areas in which animal models can provide valuable insights include the aetiology of depression, the neurobiological mechanisms underlying depressive symptomatology and mechanisms of antidepressant action. © 1997 John Wiley & Sons, Ltd.