My understanding is the 12% to 20% estimate is for people who've been diagnosed with a serious mental illness at intake, and it doesn't take into account people who might have a more moderate problem and it doesn't take into account people who become ill while they're in prison. It seems like, given the conditions that someone's in—separated from family and support and in a very different kind of environment with high discipline and so on—they would be vulnerable and probably come in vulnerable, to some extent, to developing mental health problems. So it's probably an underestimate, yes.
On October 29th, 2009. See this statement in context.