Abstract: Appropriate animal models are essential for elucidating the etiology and pathophysiology of depression. While rodent models are commonly used, the tree shrew shows promise for modeling depression. Studies of tree shrews demonstrate an evolutionary relationship to primates, a highly developed nervous system and a more similar stress system to human. Well-accepted etiological stimuli of human depression, for example, social defeat, induce depression-like behaviors in tree shrews; such behaviors can be partially improved by classic antidepressants. This article reviews the social defeat paradigm in the tree threw as a model of depression from perspectives of face, predictive, and construct validities. Underscored by a phylogenetic relationship to humans, tree shrew models of depression may provide a more clinically-relevant approach for studying the neuro-mechanisms of depression and screening antidepressants. Nonetheless, the current tree shrew depression model requires further exploration and improvement.

Key words: depression, tree shrew, social defeat, face validity, predictive validity, construct validity