PET Scan of the Brain may Predict Treatment Outcome in Depression

A simple brain scan may help doctors to predict whether depressed patients would attain benefits from antidepressant medication or psychotherapy. The metabolic activity in certain regions of the brain may be linked with the outcome of therapy in patients with major depressive disorder. Neurologist Helen Mayberg from Emory University in Atlanta, Georgia, and her colleagues found that a PET scan of the brain can reveal whether a patient will respond better to drugs or cognitive behavior therapy. The results of their work, a study to identify the first potential biomarker that distinguishes between treatment responses, have been published in JAMA Psychiatry. The brain-scan biomarker is still to be validated in further trials, meaning that psychiatrists will have to wait for another couple of years before it can be used.

Eighty-two people with untreated depression were selected for the trial. Researchers measured glucose metabolism in their brains using Positron Emission Tomography (PET) scans. Study subjects were divided into two groups; while one group received the common antidepressant drug escitalopram oxalate (a selective serotonin reuptake inhibitor, or SSRI) for 12 weeks, the other group received 16 sessions of cognitive behavioral therapy over the same period.

The right anterior insula is a part of the brain that is concerned with depression-relevant behaviors such as emotional self-awareness and decision-making. The researchers found that patients who later responded well to antidepressant medication had insula glucose-metabolism levels above the mean level for the whole brain. Below-average insula metabolism levels were found in patients who responded to cognitive behavioral therapy better.

A PET scan however is an expensive affair; its cost effectiveness with regards to its utility in depressed patients is indeed questionable. A simple blood test that can serve the purpose would be a boon; unfortunately none is available as yet. Still, a PET scan, if ultimately proved to be effective, would definitely be of immense benefit to patients since it may save them from months of ineffective therapy.

Source-Medindia