Serotonin-deficient brains more vulnerable to social stress

Mice deficient in serotonin -- a crucial brain chemical implicated in clinical depression -- are more vulnerable than their normal littermates to social stressors, according to a new study. Following exposure to stress, serotonin-deficient mice did not respond to the standard antidepressant Prozac. The results point to new strategies to help alleviate treatment-resistant depression.