Intellectual disability and prison numbers

Over America way blogfolk are examining this graph.

It's suggested that this shows substitution - that people moved out of one into the other.

Mark Kleinman disagrees.

mental-hospital patients tended to be white, female, and elderly, while prisoners are disproportionately black, male, and young.

Perhaps, but they didn't used to be. The profile up to the major deinstitutionalisations was much younger and more male.

And - big point - Institutionalization wasn't wholly, or even mainly, for the mentally ill - indeed, it's mildly interesting that the intellectual community remembers things that way. Most of the people in institutions were classified as retarded.

And there is, of course, a whopping overlap between prisoners and that fraction of the population that tests as retarded. The sorting is quite obvious; less competent people are more likely to get caught (and more likely to be able to be railroaded) and less able to mount a good defence. As a result, they're very much overrepresented. I did a quick check at one stage of the figures in Victoria (Australian state) - we have quite a reasonable care system by world standards, I don't think our figures are wildly out of line - and here....

Prisons service points out that “the prevalence of Victorian prisoners with an intellectual disability ( that is those registered with the Department of Human Services) has not exceeded the incidence of intellectual disability in the general community, remaining in a range of 1.4% to 1.8%”. I don’t want to be picky, but there’s a rather sneaky shift between the two halves of that sentence. Prisoners are classified as having an intellectual disability if they’re registered with DHS, while the general community figures are based on survey data. If we compare like with like, the proportion of people in the Victorian community registered with DHS is 21,000 out of 6∏ million, or about 0.3% - that is, DHS names are represented in prison at about six times their presence in the community. As it happens, about half the people registered with DHS are too handicapped to commit even the smallest crime, so that the remaining 10,000 must be represented at 12 times the general rate. If the general community rate of intellectual disability is in fact 1.8%, twelve times that is 21.6%, or one prisoner in every five. And, to be sure, the Department has acknowledged that “undiagnosed and/or unidentified prisoners with borderline intellectual disability or acquired brain injury [are] a significant issue”.

Some of that graph does represent moving people who test on the borderline out of institutions and into prison. A change, I may say, I'm in favor of (I have myself helped close down several institutions in Victoria), even if that's as far as the change goes; a prison is a much more stimulating environment with much higher social status and a much more valorised social role. Which isn't to say that we can't do better for them.

Mind you, what's true for Australia's much smaller relative prison population may be rendered irrelevant by America's straight-out crazy incarceration policies. And at the most desirable point on the graph both lines were low; we should aim for that sweet spot.