Does the behavioral "despair" test measure "despair"?

The behavioral "despair" test is widely used to study antidepressants, mainly on the theoretical assumption that the test animal becomes desperate. In view of the above, we compared behavior of animals subjected to various experimental conditions (4, 15, 30 cm of water), in order to assess whether or not "despair" was the cause of immobility. Our results indicate that the animal's behavior in response to exposure to a dangerous situation, such as that represented by 15 or 30 cm water, depends upon previous knowledge of the environment rather than "despair." We concluded that this test is far from reproducing behavioral changes which characterize depressive illness in humans.