title: Immobility in the forced swim test is adaptive and does not reflect depression.
abstract: The forced swim test is based on the progressive immobility a rodent displays when immersed in a beaker filled with water from where no escape is possible. While the test was originally designed to identify the antidepressant potential of drugs, over the past decade a rapidly growing number of publications (more than 2000) portray this immobility response anthropomorphically as a measure for depression and despair. This is incorrect. The response to the forced swim stressor should be considered for what it shows: a switch from active to passive behavior in the face of an acute stressor, aligned to cognitive functions underlying behavioral adaptation and survival.
authors.affiliation: Institute of Psychology, Leiden University and Leiden Institute for Brain and Cognition, Leiden University Medical Center, Leiden, The Netherlands. Electronic address: m.l.molendijk@fsw.leidenuniv.nl.
authors.forename: Marc L
authors.initials: ML
authors.lastname: Molendijk
authors.affiliation: Department of Endocrinology and Metabolic Disease, Leiden University Medical Center, Leiden, The Netherlands. Electronic address: e.kloet@lacdr.leidenuniv.nl.
authors.forename: E Ronald
authors.initials: ER
authors.lastname: de Kloet
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D003863:Depression / Q000503:physiopathology* / Q000523:psychology; D003866:Depressive Disorder / Q000503:physiopathology* / Q000523:psychology; D004195:Disease Models, Animal; D013315:Stress, Psychological / Q000503:physiopathology / Q000523:psychology; D013550:Swimming / Q000523:psychology
keywords: Depression; Forced swim test; Glucocorticoids; Mouse; Rat; Stress