Distinguishing generalized anxiety disorder from major depression: Prevalence and impairment from current pure and comorbid disorders in the US and Ontario

Kessler RC, Berglund PA, DeWit DJ, et al.
Ronald C. Kessler
International Journal of Methods in Psychiatric Research
http://www.ncbi.nlm.nih.gov/pubmed/?term=Distinguishing%20generalized%20anxiety%20disorder%20from%20major%20depression%3A%20Prevalence%20and%20impairment%20from%20current%20pure%20and%20comorbid%20disorders%20in%20the%20US%20and%20Ontario.