PET Scan Predicts Whether Drugs, Therapy Will Best Treat Depression

A recent pretreatment imaging scanning study of brain activity has forecasted whether depressed patients would best achieve remission with an antidepressant medication or psychotherapy.

If a patient’s pretreatment resting brain activity was low in the front part of the insula, on the right side of the brain (red area where green lines converge), it signaled a significantly higher probability of remission with cognitive behavior therapy (CBT) and a poor response to escitalopram, a serotonin-specific reuptake inhibitor (SSRI) antidepressant. Conversely, hyperactivity in the insula predicted remission with escitalopram and a poor response to CBT.

“Our goal is to develop reliable biomarkers that match an individual patient to the treatment option most likely to be successful, while also avoiding those that will be ineffective,” explained Helen Mayberg, MD, External Web Site Policy, of Emory University (Atlanta, GA, USA), a grantee of the US National Institutes of Health’s (NIH) National Institute of Mental Health (Bethesda, MD, USA).

Dr. Mayberg and colleagues reported their findings June 12, 2013, in JAMA Psychiatry. “For the treatment of mental disorders, brain imaging is still primarily a research tool, yet these results demonstrate how it may be on the cusp of aiding in clinical decision-making,” said NIMH director Thomas R. Insel, MD.

Currently, determining whether a specific patient with depression would best respond to psychotherapy or drug is based on trial and error. In the absence of any objective guidance that could predict improvement, clinicians typically try a treatment that they, or the patient, prefer for one month or two to see if it works. Therefore, only approximately 40% of patients achieve remission following initial treatment. This is expensive in terms of human suffering as well as healthcare spending.

Dr. Mayberg’s team hoped to identify a biomarker that could predict which type of treatment a patient would benefit from based on the state of his or her brain. Using a positron emission tomography (PET) scanner, they imaged pretreatment resting brain activity in 63 depressed patients. PET targets what areas of the brain are active at any given moment by tracing the destinations of a radioactively tagged form of glucose, the sugar that fuels its metabolism. They compared brain circuit activity of patients who achieved remission following treatment with those who did not improve.

Activity in one specific brain area was seen as a pivotal predictor of outcomes from two standard forms of depression treatment: CBT or escitalopram. If a patient’s pretreatment resting brain activity was low in the front part of an area called the insula, on the right side of the brain, it signaled a substantially higher likelihood of remission with CBT and a poor response to escitalopram. Conversely, hyperactivity in the insula predicted remission with escitalopram and a poor response to CBT.

Among several areas of brain activity related to outcome, activity in the anterior insula best predicted response and non-response to both treatments. The anterior insula is known to be important in regulating emotional states, self-awareness, decision-making, and other mental tasks. Alterations in insula activity have been seen in studies of a range of depression therapies, including medication, vagal nerve stimulation, and deep brain stimulation.

Emory clinical neuroscientists have examined brain scans in effort to find better ways to help patients recover from depression. “If these findings are confirmed in follow-up replication studies, scans of anterior insula activity could become clinically useful to guide more effective initial treatment decisions, offering a first step towards personalized medicine measures in the treatment of major depression,” concluded Dr. Mayberg.

Related Links:
Emory University
National Institute of Mental Health