Glenn Reynolds raises an important issue in this post about mental illness and homelessness, and collects a number of good anecdotes, but it seems like there's still a bit of misinformation floating about. Let's start with the numbers. It's very difficult to know how many homeless people are mentally ill: estimates range pretty widely, often as high as 50 percent or so. Often these numbers measure different things—how ill is mentally ill? is a meth addict mentally ill? perhaps he may as well be, perhaps not—and obviously we would recommend different solutions for different levels of mental illness.

But we can pin a few things down with fair precision—the 1992 Federal Task Force on Homelessness and Severe Mental Illness pegged the number of homeless people requiring time in an institution at only 5-7 percent. I haven't come across any other numbers on this, and I'll assume it's pretty reliable. So yes, the de-institutionalization movement certainly turned a lot of people out onto the streets, and I'd agree that it was done poorly, but that's very different from saying that it caused the current epidemic of homeless people. And it's very different from saying we should fill the mental hospitals back up as a means of tackling homelessness.

It's important to note, I think, that it wasn't merely budget pressures or the concerns over patient's rights—as immortalized in One Flew Over The Cuckoo's Nest—that led to state hospitals turning people out in droves. The development of new psychoactive medicines also played a big part; doctors had little idea that medication alone doesn't suffice for treatment. At the same time, psychiatry was looking more favorably at early forms of community-based treatment. In the 1960s, federal aid finally became available to the mentally ill, and community mental health centers were set up. So the country at least had the basis for a new form of treatment, one that really was far more appropriate for a good number of the mentally ill, many of whom now can enjoy relative freedom (as compared to being locked in a hospital).

The problem, of course, was that not all communities kept these services in place—the quality of these shelters and homes vary from region to region, and there's a pretty dire need for more aggressive case management. There's also a dire need for mental health services in prisons: a small, much too small, percentage of mentally ill prisoners receive treatment, even though many of these people are locked up precisely because that's the quickest way to get them into treatment. (You are far more likely to be locked up in prison for disorderly conduct if you're mentally ill, period.)

So it's a complex topic, as you'd expect, and I've brushed over it all far too quickly. Glenn's right in that there really is a resistance to recognizing that some homeless people are simply intractable, and can't be helped by even the most aggressive case management. At some point, institutionalization becomes the only option. But there are also a lot of intermediate steps between an open shelter and a hospital bed, and saying, as Jeff Jarvis does, that "the real issue isn't homelessness… [i]t's insanity," badly elides all that.