It's widely assumed that there is some overlap between depression and obsessive compulsive disorder. But, like most psychiatric illnesses, diagnosis of the two remains almost as much an art as a science, with mental-health professionals relying on a combination of their own observations, patient behavior and patient self-reporting. Psychiatry is actively looking for biomarkers that can help the diagnostic process along. Researchers at Wayne State University in Detroit say they have found a way to differentiate between children with major depressive disorder from "normal" children, in addition to telling them from children with obsessive compulsive disorder. Cortical thickness, they say, can help tell the difference.
"The findings from our study are very exciting," said researcher David Rosenberg in a statement. "By measuring cortical thickness, we were able to distinguish depressed children not only from healthy children without depression, but also from those with another psychiatric disorder, obsessive compulsive disorder."
While the press release from Wayne State optimistically pronounces: "This study offers an exciting new way to identify more objective markers of psychiatric illness in children," not all psychiatrists are convinced. Writing in his Thought Broadcast blog, psychiatrist Steve Balt warns that there are "many shades of grey between 'depression' and 'OCD': some depressed children will certainly have OCD-like traits, and vice versa. Treating the individual (and not necessarily the individual's brain scan) is the best way to care for a person."