The forced swim test (FST) is an experiment commonly used to evaluate the emotional state and the effect of antidepressant drugs in mice or rats. In experiments, animals are forced to swim in water for a period of time, and their subsequent surfacing and movements are used as a measure of depressive-like behavior. Antidepressant drugs often extend the swimming time of animals and are considered to have antidepressant effects. FST is widely used for drug screening and understanding the neurobiological basis of depressive symptoms, but it is also subject to some ethical and methodological controversies.