Experimental Animal Models for Depressive Disorders: Relevance to Drug Discovery

Major depressive disorder is a complex mental disorder imposing severe social and economic burden worldwide. Numerous animal models have been developed to elucidate the pathophysiology that underlies depression and to test novel antidepressant treatment strategies. Here, we provide a brief summary of the animal models that are typically used in experimental settings. We discuss genetic models, including the recently developed optogenetic tools as well as models based on stress exposure, such as the social stress, chronic mild stress, and early-life stress paradigms. Finally, we summarize their value in drug development.