Depression Is ContagiousDepression is the world's most common mood disorder, and it's spreading fast: at the current rate, the World Health Organization predicts it will leap from the fourth to the second greatest cause of human suffering and disability in the world by the year 2020. And the shocking spread of this debilitatingdisorder isn't fated by brain chemistry, genes, diet, or personal weakness, as we're too often taught rather, the latest research provides