Chapter 1 - Models of Depression

The incidence of depressive illness is high in the United States and worldwide, and the inadequacy of currently available drug treatments contributes to the significant health burdenassociatedwithdepression. Abasicunderstandingof the underlying disease processes in depression is lacking, and therefore, recreating the disease in animalmodels is not possible. Currently usedmodels of depression attempt to produce quantifiable correlates of human symptoms in experimental animals. The models differ in the degree to which they produce features that resemble a depressive-like state, and models that include stress exposure are widely used. Paradigms that employ acute or subchronic stress exposure include learned helplessness, forced swim test, and tail suspension test, which employ relatively short-term exposure to inescapable or uncontrollable stress and can reliably detect antidepressant drug response. Longer-term models include chronic mild stress models, early-life stress models, and social conflict models, which may more accurately simulate processes that lead to depression.