I want to begin by saying I don't have any insider info into the process and I don't have an opinion about what's going on. Which is good, because no one asks me.
The DSM is a book that lists the guidelines for making psychiatric diagnoses. It's like a Chinese Menu--- a few symptoms from column A, a few symptoms from Column B, and voila, you've got Diagnosis X. There have been 4 versions to date, and the 5th is in the works.
It would be nice if we could run a definitive test and say, Yup, the Depression Factor is present in your blood, you've got Major Depression, single episode, and the level is 75 so it's "moderate." Or look, the left side of the amygdala is enlarged, therefore it's Panic Disorder. Or, the frontal region has increased metabolism when you burp, so you've got Paranoid Schizophrenia.
It doesn't work that way, we don't have any definitive tests and when we do tests in psychiatry as part of a diagnostic evaluation. It's to make sure the patient doesn't have a brain tumor or a stroke or thyroid dysregulation or hypoglycemia or some other medical condition (that we can see or measure) that explains the symptoms. If the brain looks anatomically normal, if the blood is normal, if there are no funny substances that explain why someone is acting or feeling either badly or weirdly, then by default, it's a psychiatric problem. Some day this may change, but right now that's it. Researchers are making progress towards finding links between psychiatric illnesses (after they are diagnosed as such) and specific genetics or brain metabolic differences, but they don't make a diagnosis and it's all pretty new.
So how are diagnostic criteria decided? A bunch of people sit in a room and decide. They talk, they look at research findings, they pool their experience, and actually I'm not all that sure (keep reading, there are some answers below). The issue of diagnostic criteria and validity is laden with emotion-- there are people who like psychiatric labels, like the drug companies. And there are people who don't like labels -- like those who don't want their sexual preferences or gender distress labeled an illness, Health insurance companies pick and choose what diagnoses they will reimburse for. So once upon a time, homosexuality was a psychiatric illness and it's not anymore.
The DSM-V work groups are in place and these peeps are talking about the next volume and what should change. There have been issues with the process of what they are doing-- the members of these groups signed a non-disclosure document, and my email (why me?) gets messages from people complaining that the process is too secretive, and other messages stating that there is a need for some confidentiality during the process, but it's open and transparent. Today's email came from the American Psychiatric Association, pointing me to a Wall Street Journal blog post about the issue, so I will guide you to that: Click Here.
Oh, and while you're clicking, Roy also posted on this issue back in November: Click Here.
Oh, and here's what the APA has to say about the how the process transpires:
The work groups began meeting in late 2007. While the 13 work groups reflect the diagnostic categories of psychiatric disorders in the previous edition DSM-IV, it is expected that those categories will evolve to better reflect new scientific understanding. With the understanding that some continuity from DSM-IV to DSM-V is desirable to maintain order in the practice of psychiatry and continuity in research studies, there has been no pre-set limitation on the nature and degree of change that work groups can recommend for DSM-V.
Each work group meets regularly, in person and on conference calls. They begin by reviewing DSM-IV’s strengths and problems, from which research questions and hypotheses are first developed and then investigated through literature reviews and analyses of existing data. They will also develop research plans, which can be further tested in DSM-V field trials involving direct data collection. In order to invite comments from the wider research, clinical, and consumer communities, the APA launched a DSM-V Prelude Web site in 2004, where these groups could submit questions, comments, and research findings to be distributed to the relevant work groups.
Based on this comprehensive review of scientific advancements, targeted research analyses, and clinical expertise, the work groups will develop draft DSM-V diagnostic criteria. A period of comment will follow, and the work groups will review submitted questions, comments, and concerns. The diagnostic criteria will be revised and the final draft of DSM-V will be submitted to the APA’s Council on Research, Assembly, and Board of Trustees for their review and approval. A release of the final, approved DSM-V is expected in May 2012.
You can read the whole APA web page about this: Click Here.