This article updates of the association between mental disorders and earnings.  The authors found that a DSM-IV serious mental illness in the preceding year predicted reduced earnings, averaging $16,306 less than controls.  At a societal level, those losses would total $193.2 billion of which 75 percent is due to reduced earnings on mentally ill persons with any earnings and the remainder is due to reduced probability of having earnings. 

Individual and societal effects of mental disorders on earnings in the United States:  results from the national co-morbidity survey replication. American Journal of Psychiatry, 165: 703-711. DOI: 10.1176/appi.ajp.2008.08010126 http://ajp.psychiatryonline.org/cgi/content/abstract/165/6/703

Authors: Ronald C. Kessler, Steven Heeringa, Matthew D. Lakoma, Maria Petukhova, Agnes E. Rupp, Michael Schoenbaum, Philip S. Wang, Alan M. Zaslavsky