AdvertisementAddicts' Brains May Be Wired At Birth For Less Self-ControlFebruary 03, 2012Jon HamiltonfacebookEmailThe red areas show gray matter that is abnormally increased in drug users. Blue shows gray matter that is abnormally decreased in drug users. Yellow shows white matter tracts, called fractional anisotropy or FA. FA is significantly reduced in both the drug users and in their siblings, which suggests that the white matter tracts work less efficiently. (Science/AAAS)