PIM-35

The Tail Suspension Test is a mouse behavioral assay in which an animal is suspended by the tail in an inescapable position, causing alternating escape-directed activity and immobility; the main readout is immobility time, and antidepressant-like treatments generally reduce immobility compared with vehicle controls. The assay detects behavioral response to acute inescapable stress rather than a molecular event; immobility is interpreted as passive stress-coping behavior, while reduced immobility is used as a predictive screen for antidepressant-like activity, with important limitations related to strain, locomotor activity, and tail-climbing behavior.

The Forced Swim Test is a rodent behavioral assay in which a mouse or rat is placed in an inescapable cylinder of water, and the main readout is the time spent immobile versus active escape-related behaviors such as swimming or climbing. Reduced immobility after treatment has historically been interpreted as antidepressant-like activity, but the assay should be interpreted as a behavioral response to acute inescapable stress rather than a complete model of human depression.