Sex differences in behavioral despair: relationships between behavioral despair and open field activity.

Many studies have reported sex differences in the rates of depression in humans. Due to experimental problems, the nature of these sexual differences is still unknown. In the present study, we quantify the sex differences in depression using two animal models. Both the Porsolt et al. test and the Hilakivi and Hilakivi forced swimming test have shown that the duration of immobility is higher in the male than in the female. Sexual differences in the animal models of depression are probably unrelated to general activity differences because there is no significant correlation between activity in both tests. However, the correlation between the two models of depression used reached statistical significance. Finally, the immobility levels in the Porsolt test were similar in the different stages of the estrous cycle.