A Miami psychiatrist who writes prescriptions for Medicaid patients at a rate of 150 a day, seven days a week, has been targeted by Sen. Charles Grassley (R-IA) as an example of why the federal government should do more to investigate over-utilization of healthcare. The letter from Grassley to federal Medicaid officials comes at a time when authorities are looking for ways to reduce what experts believe is massive overspending in areas like Miami, where healthcare costs can be more than twice the national average, the Miami Herald reports.