PROVIDENCE – A new study led by Dr. Mark Zimmerman, director of outpatient psychiatry at Rhode Island Hospital, has found that a majority of doctors and a substantial minority of psychiatrists don’t use the established criteria when diagnosing major depressive disorder in patients.
The finding is important, Zimmerman and his colleagues said, because if the right criteria aren’t being used, many patients who are being diagnosed as depressed – and are being prescribed antidepressants – may be taking drugs that are unlikely to help them.
Most mental-health professionals rely on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), to define mental problems and diagnostic criteria. For major depressive disorder, the criteria have been virtually the same for nearly 30 years. But in previous studies, Zimmerman and colleagues have questioned how useful they are.
For this study, published in the Journal of Clinical Psychiatry, Zimmerman and his team asked physicians and psychiatrists attending a continuing medical education conference to complete a six-item questionnaire. A total of 291 doctors responded.
One of the questions asked how often they follow the DSM-IV criteria for major depressive disorder when diagnosing depression, offering a choice of less than 25 percent of the time, 26 to 50 percent, 51 to 75 percent, or more than 75 percent.
Nearly a quarter of the psychiatrists said they used the criteria less than half the time, and more than two-thirds the non-psychiatrist doctors said the same.
“These findings are disconcerting,” said Zimmerman. “While the symptom criteria for diagnosing MDD have not been changed much over the last 30 years, psychiatrists, especially older psychiatrists, apparently have not uniformly embraced their use, and non-psychiatrist physicians seem to have rejected the formal application of the criteria.”
Zimmerman, who is also an associate professor of psychiatry and human behavior at Brown University’s Warren Alpert Medical School, theorized that doctors aren’t using the criteria because they’re too long, and they may not be able to remember them in full. If that’s the case, he said, a shortened definition might help.
Older psychiatrists were less likely to report using the DSM-IV criteria than younger psychiatrists, and Zimmerman theorized that maybe if they were trained in the pre-DSM-III era, they “never bought into the importance of using operational criteria to make a diagnosis.”
For patients, the bottom line is that a depression diagnosis may not really correspond with the definition of major depressive disorder.
The researchers noted that the study has limitations, such as that they didn’t ask doctors why they didn’t follow the guidelines, if they didn’t, and some of the results might be subject to different interpretations. In addition, the survey sample wasn’t random, so it might not be representative of doctors across the country.
