Maggie's Farm had two links about psychiatric diagnoses - Stuart Schneirman's is the better one. I get my back up about these, because so much of my job is involved with people who insist they have no illness at all, and decades of people quoting Szasz or RD Laing insisting that what we call illnesses are indictments of society rather than anything wrong with the patient. You can still find people in social work who will claim that poverty and the inability to navigate systems of power are the cause of mental illness. I tend to be dismissive with such thinking. If you deal with people who are in acute crisis who have schizophrenia, BPAD manic phase, or schizoaffective disorder, you come away very impressed with the rEality of these disorders. If you work with people with severe depression, who were award winning real estate agents a year ago but will now soil themselves in bed because they cannot get up you get tired of listening to people blather about attitude or nutrition. People whose kids have autism know that this is some processing disorder that has to be worked around, and it wasn't their cold parenting that caused it. To me, people who are dismissive about diagnosis are complaining about events at the margin. The various DSM's have made very useful distinctions among illnesses.
Texan99's comment at Maggie's that it's not usually schizophrenia these critics are talking about was refreshing, because I think it is now true. My complaint is outdated, perhaps by decades, because that battle has been largely won, though mop-up operations will continue, similar to what is happening with vaccinations. What I considered "the margins" is actually the part of the mental health system that most people encounter. Perhaps as much as 90%? I don't know, I have no numbers on this. My patients are in the 1-2% of the population for illness, and also the least-functional or most dangerous of those.
For those other conditions, or the milder versions of them, I think the critics have some good points. We have looked at Borderline Personality Disorder differently over the decades, separating a number of patients out into PTSD or anxiety disorders. We now more automatically look at a person with depression as someone who might be better understood as having an anxiety disorder, and vice versa. OCD is now fully classifed as an anxiety disorder, which seems sensible to me.
The highly-politicised aspects of the DSM I don't tend to think about, because it doesn't affect us much. That we are clearly "not allowed" to conclude that someone has autogynephilia can usually be worked around, because in crisis, longterm philosophical issues are usually a distraction. For the same reason, gender differences in rates of diagnosis only concern us a bit. Are Antisocial Personality Disorder and Borderline Personality Disorder the same genetic or prenatal condition subjected to different hormones and/or cultural expectations? Perhaps, but not that interesting to me. We are trying to manage assault, self-harm, suicide here.
There is considerable overlap between diagnoses, especially among children. A psychiatrist friend once said "from the neck down, we're mostly just frogs. Big frogs, but frogs." Our bodies have only a limited number of responses, and it's the interpretive aspect from very complicated brains that make much of the difference. Yet just because it is difficult to state exactly where the RockIes begin does not mean that mountains do not exist. Even bodies of water, which are much more sharply defined, have littoral areas. Nonetheless, oceans exist.