The behavioural despair test (also called the Porsolt test or forced swimming test) is a test used to measure the effect of antidepressant drugs on the behaviour of laboratory animals (typically rats or mice).

Method

Animals are subjected to two trials during which they are forced to swim in an acrylic glass

Acrylic glass

Poly is a transparent thermoplastic, often used as a light or shatter-resistant alternative to glass. It is sometimes called acrylic glass. Chemically, it is the synthetic polymer of methyl methacrylate...

cylinder filled with water, and from which they cannot escape. The first trial lasts 15 minutes. Then, after 24-hours, a second trial is performed that lasts 5 minutes. The time that the test animal spends without moving in the second trial is measured. This immobility time is decreased by antidepressants.

Controversy in interpretation

Classically, the results of this test have been interpreted such that immobility in the second test is a behavioural correlate of negative mood, representing a kind of hopelessness in the animal. However, there is some debate between scientists whether increased immobility instead demonstrates a learning within the animal and a positive behavioural adaptation, i.e. the animal has learnt it can't escape and is conserving energy until it is removed by the experimenter.