The economic burden of depression in the United States: how did it change between 1990 and 2000? - Greenberg,P.E.; Kessler,R.C.; Birnbaum,H.G.; Leong,S.A.; Lowe,S.W.; Berglund,P.A.; Corey-Lisle,P.K. (J Clin Psychiatry, 2003)