a) the DSM isn't perfect
Of course not... I wonder when/if the DSM 6 will come out...
practitioners who may not being using the tool appropriately
Example Intermittent Explosive Disorder... The names speaks for itself in that some children become totally enraged and..explode.
Sometimes used to label kids and be done for the day. The implication of this is that, this diagnosis can act as a band aid and not getting down to the root of things for WHY the child is upset. This is how a person can fall through the cracks.
Of course not... I wonder when/if the DSM 6 will come out...
Most of the problems with the DSM are institutional. I would expect the DSM 6 to have them as well. The way forward would be for another institution to provide a new medical diagnostic system.
The European medical establishment might do this.
http://lesswrong.com/r/discussion/lw/oe0/predictionbased_medicine_pbm/ might also lead to an organization that has the capability to develop a new and better diagnostic system. An organisation that could easily provide treatments for stupidity.
It's great to make people more aware of bad mental habits and encourage better ones, as many people have done on LessWrong. The way we deal with weak thinking is, however, like how people dealt with depression before the development of effective anti-depressants:
The only "anti-stupidity drugs" we have are nootropics. But the nootropics we have weren't developed as nootropics. Piracetam was, I think, developed to treat seizures. L-DOPA was developed to treat Parkinson's. No one knows who started using ginkgo biloba or what they used it for; it was used to treat asthma 5000 years ago. Adderall derives from drugs used to keep soldiers awake in World War 2.
And none of them are very good against stupidity. AFAIK, to date, not one drug has been developed by understanding and targeting the causes of different types of stupidity. We have the tools to do this--we could, for instance, sequence a lot of peoples' DNA, give them all IQ tests, and do a genome-wide association study, as a start.
We don't research these things because society doesn't want to research them. People don't conceive of stupidity as a disease that can be cured. We need, somehow, to promote thinking of stupidity as a mental illness. As something drug companies could make billions of dollars off of.