The risk of developing major depressive disorder (MDD) surges during adolescence-particularly for females. Cognitive behavioral therapy (CBT) may be an effective treatment, but only about half of girls diagnosed with depression demonstrate significant improvement. Researchers at Harvard Medical School and McLean Hospital have identified a noninvasive evaluation of brain function which might help predict who will react to CBT.
"The study is very significant because it suggests that readily acquired EEG measures related to processing of rewards and losses can serve as biomarkers for predicting treatment response and tracking the effects of therapy in the brain," said Cameron Carter, Editor of Biological Psychiatry: Cognitive Neuroscience and Neuroimaging. "Future work using these measures may help clinicians determine the best treatment - for example, CBT versus medications - for a given young person suffering with depressive symptoms."
The study included 36 teenage girls with MDD and 33 healthy adolescents. Girls with MDD were provided a 12-week path of CBT. All in all, the girls who underwent treatment saw a substantial improvement in their symptoms from the"severe" to"mild" range.
All were given a task, like a video game, where they could win or lose money. The researchers utilized electroencephalography (EEG), which measures brain activity from outside the skull, to examine participants' brain responses throughout the task. The girls repeated the task (along with the EEG test) in the midpoint of treatment, and after completion of treatment. Control participants, that did not receive CBT, also performed the job and EEG measurements at three corresponding occasions.
The investigators measured brain signals called event-related potentials (ERP), which are signature responses observed during such tasks. One type of ERP reflects the mind's immediate response to monetary rewards vs. losses; this step didn't predict who would respond to CBT. Another, longer-lasting kind of ERP reflects the brain's more sustained emotional processing of rewards vs. losses.
"We found that the brain measure of sustained - but not initial - responsiveness to rewards predicted greater symptom improvement, which may help to inform which depressed adolescents are most likely to benefit from CBT," said Christian Webb, PhD, lead author of the study.
Although the precise mechanisms that account for symptom improvement In CBT for depressed teens isn't yet apparent, this study also revealed that EEG responses to financial loss changed over time with treatment. That finding, Dr. Webb said, may reflect that, "in addition to reducing depressive symptoms, successful CBT may attenuate underlying neural hypersensitivity to negative outcomes among depressed adolescent girls," ultimately leading to symptom improvement.
Related Journal Article: https://www.sciencedirect.com/science/article/abs/pii/S2451902220302007?via=ihub