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Bagby completes DSM field trials

Michael Bagby

Michael Bagby, professor of psychology, just completed a field trial that could help redefine how mental disorders are diagnosed and treated.

Bagby tested proposed changes to the American Psychological Association’s (APA) Diagnostic and Statistics Manual (DSM), which present a complete list of mental disorders and their symptoms. It’s used by clinicians to diagnose patients and bill insurers, and by researchers studying disorders and treatments.

“This new DSM reflects an effort to change our Bible,” says Bagby. “If you want to give a diagnosis, you have to use the DSM.”

Bagby comes to UTSC this year from the Centers for Addiction and Mental Health (CAMH), where he remains a senior scientist. He wrote the proposal for CAMH to handle the study, and served as primary lead. CAMH was one of only 11 institutions in North America to be granted a trial, and the only one in Canada.

The first DSM was published in 1952, and has since gone through a number of revisions. The new DSM, called DSM-5, is expected to be finished by 2013.  Bagby says that the new version makes sweeping changes to the way disorders will be classified. For one thing, it introduces some new disorders, such as premenstrual dysphoric disorder, while folding others into broader categories. For instance, Asperger’s Syndrome will be absorbed into the more general category of Autism Spectrum Disorder.

In addition, the new version includes a dimensional component. Rather than simply declaring that a person does or does not have a condition, it will recognize that conditions can range from mild to severe.

The new diagnostic criteria were proposed by expert panels that deliberated for 10 years. The field trials are designed to make sure the criteria are feasible, useful, reliable and valid.

Bagby’s trial tested the new criteria for personality disorders, schizophrenia, schizoaffective disorder, and attenuated psychotic symptoms syndrome. To conduct the trials, Bagby and his colleagues assessed hundreds of CAMH patients according to the new DSM-5, repeating each assessment three times to make sure different raters arrived at the same diagnosis.

© University of Toronto Scarborough