Animal model of depression.

A behavioural procedure is described which may provide an animal model for some aspects of human depression. Rats or mice when forced to swim in a restricted space will rapidly cease attempts to escape and become immobile. Immobility is reduced by many clinically effective antidepressant treatments suggesting that the immobile behaviour may reflect a state of lowered mood in the animal. If so the method could be useful as a simple experimental tool for research into the biology and therapeutics of depression.