Behavioural despair test

The behavioural despair test (or Porsolt forced swimming test) is a test, centered around a rodent's response to the threat of drowning, whose result has been interpreted as measuring susceptibility to negative mood. It is commonly used to measure the effectiveness of antidepressants, although significant criticisms of its interpretation have been made.

Method
Animals are subjected to two trials during which they are forced to swim in an acrylic glass 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, immobility in the second test has been interpreted as a behavioral correlate of negative mood, representing a kind of hopelessness in the animal. Rodents given antidepressants swim harder and longer than controls (which forms the basis for claims of the tests validity). However, there is some debate between scientists whether increased immobility instead demonstrates a learning within the animal and a positive behavioral adaptation, i.e. the animal has learned it can't escape and is conserving energy until the experimenter removes it. As for any behavioral paradigm, it is extremely important to display the appropriate control groups when presenting results obtained using the forced swimming test. The term "behavioral despair test" bears an anthropomorphic connotation and is a somewhat subjective description as it is uncertain whether the test reliably gauges mood or despair. Strictly speaking, the descriptive term "forced swimming test" should be preferred.