Dr. John E. Helzer, a psychiatrist who directs the Health Behavior Research Center at the University of Vermont, Burlington, said there are clear drawbacks to revising the DSM-IV, including disruption to clinicians and investigators, “because we have to learn to apply new diagnostic definitions. It sacrifices a longitudinal perspective because if you do population prevalence surveys with one set of diagnostic criteria and go out a few years later and do a different survey with a different set of criteria, it's very hard to compare the results.”
However, in his opinion, the shaping of the DSM-V provides an opportunity to create a more quantitative approach to making psychiatric diagnoses. “DSM has always been a categorical system; you either have a diagnosis or you don't,” said Dr. Helzer, a co-author of the Diagnostic Interview Schedule. “It does not allow for gradations of severity. If we can use things like item response theory and differential weighting to have a scaled score rather than a yes/no diagnosis, that's going to be immensely helpful, not only clinically but also in terms of our research work.”
He described the DSM-IV as a top-down diagnostic system and the DSM-V as a bottom-up diagnostic system. A top-down system “begins with expert committees that propose disorders, they decide the criteria and the thresholds, and that becomes a classification system,” he explained.
A bottom-up system, on the other hand, begins “with a large pool of data on problems; we use statistical analysis to identify thresholds, and that becomes a classification system,” Dr. Helzer said.
“The difference is the input of the clinical experts. There is heavy input of clinical experts in the top-down approach versus very little in the bottom-up approach,” he said.
“It's a very legitimate question about which of the two [approaches] would be more appropriate and give us a more valid diagnosis, but it seems that this is an opportune time for us to make this comparison.”
It would be helpful to have fetal alcohol spectrum disorder in the DSM so psychiatrists can bill for services.
Source DR. MOSS