Of the 220 Medicare Shared Savings Program (MSSP) accountable care organizations (ACOs) in 2012, 60% had at least one participating mental health professional. Across these organizations each had an average of 26 and a median of 11 participating mental health professionals, such as psychiatrists, psychologists, or clinical social workers. Across the ACOs that had a participating mental health professional, the number ranged from just one to 240. About 10% of MSSP ACOs had 75 or more participating mental health professionals. Of the MSSP ACOs that included a mental health professional, 55% of the professionals were psychiatrists, 39% were clinical social . . .