About a decade ago, Medicaid programs were struggling to keep up with skyrocketing prescription drug costs. Between 1997 and 2002, drug spending in the program for low-income Americans grew by about 20 percent annually. ... Medicaid directors began looking for ways to tamp down on those costs. One of the most popular policies was something called "prior authorization" for a new wave of more expensive, anti-psychotic drugs ,... These policies, in a sense, worked: they helped rein in how much Medicaid spent filling prescriptions. But in another sense, they may not have worked at all: a growing body of research has begun questioning whether restricting drug spending may have just shifted costs elsewhere -; particularly, into the prison system (Sarah Kliff, 7/22).