This article examines the use of a controversial prior authorization policy in the Michigan Medicaid program on antidepressant use and and health outcomes for dually eligible Medicaid and Medicare enrollees with a Social Security Disability Insurance designation of permanent disability.  The study found that prior authorization was associated with increased use of preferred drugs with no evidence of adverse events among new users; however, there were unintended effects on treatment initiation and switching among patients already taking the drug. 

Adams, A. S., F. Zhang, et al. (2009). Prior authorization for antidepressants in Medicaid: effects among disabled dual enrollees. Archives of Internal Medicine, 169(8): 750-6.  http://archinte.ama-assn.org/cgi/content/abstract/169/8/750

Authors: Alyce S. Adams, Fang Zhang, Robert F. LeCates, Amy Johnson Graves, Dennis Ross-Degnan, Daniel Gilden, Thomas J. McLaughlin, Christine Lu, Connie M. Trinacty, Stephen B. Soumerai