Campbell-Sills L, Sherbourne CD, Roy-Byrne P, Craske MG, Sullivan G, Bystritsky A, Lang AJ, Chavira DA, Rose RD, Shaw Welch S, Stein MB. Effects of co-occurring depression on treatment for anxiety disorders: analysis of outcomes from a large primary care effectiveness trial. J Clin Psychiatry. 2012; 73(12):1509-16.