New way to diagnose disorders

Martin Sellbom.
Martin Sellbom.
University of Otago researcher Associate Prof Martin Sellbom is "very optimistic" that a new, evidence-based system for classifying mental health disorders will attract growing support.

Prof Sellbom, of the Otago psychology department, is part of a group of 50 leading international psychologists and psychiatrists who have proposed the new diagnostic model.

He was "very pleased to be on board" and hoped there would be a "paradigm shift" in how mental illnesses were classified and diagnosed. Their study appears in the American Psychological Association’s Journal of Abnormal Psychology.

Their new Hierarchical Taxonomy of Psychopathology (HiTOP) addresses limitations in the reliability of traditional models such as the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), the American Psychiatric Association’s authoritative handbook used by clinicians around the world to diagnose and treat mental disorders.

Prof Sellbom said the new system reflected growing misgivings with some of the "very rigid" approaches in traditional models.

HiTOP was a new system which was rooted  in cumulative scientific knowledge, unlike the current DSM-5.

The DSM-5 approach relied on "categorical" diagnoses which were made if a person had a required number of specified symptoms, but there was "no actual scientific basis" for a qualitative change when the required threshold was reached.

"People with fewer symptoms are often just as impaired, but are considered to have no diagnosis."

By contrast, HiTOP relied on "continuous" representations of  problems, which recognised that some significant problems "don’t currently meet full DSM diagnostic thresholds".

Patients would also benefit, including through "more flexible" diagnosis, he said.

john.gibb@odt.co.nz

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