Yahoo! News - Depression Not Uncommon During Pregnancy: "The results of a review of studies involving more than 19,000 patients suggest that rates of depression during pregnancy are high. This might be especially true during the second and third trimesters."

Concussion Causes Emotional Disturbances, Say Researchers: "Researchers from the University of Toronto and the Toronto Rehabilitation Institute have documented negative mood disturbances such as depression and confusion resulting from sports concussions for the first time."