Katie Burkhouse, assistant professor of psychiatry in the UIC College of Medicine, and colleagues conducted the study to determine whether reward positivity (RewP) can predict which patients would do better on selective serotonin reuptake inhibitor (SSRI) versus cognitive behavioral therapy (CBT) and also, whether changes in reward positivity were associated with symptom improvement over the course of treatment.
In a previous study, Burkhouse showed that lower electrical activity in the brain in response to receiving a reward – known as the reward positivity – was associated with greater symptoms of depression. When someone experiences something rewarding in their environment, their brain reacts with an increase in activity. However, patients with depression tend not to respond to rewards at the same level as healthy controls. These differences in electrical activity in response to receiving rewards can be measured using electroencephalography, or EEG, which records electrical signals from the brain through the scalp using a cap embedded with electrodes. A larger reward positivity signal reflects an enhanced brain response to receiving a reward.
For the study, Burkhouse and her colleagues recruited 63 patients having a history of anxiety or depression and 25 healthy participants with no history of mental health problems. The participants performed a simple computer task while wearing an EEG cap. Next, participants with anxiety or depression were randomly chosen to take an SSRI every day for 12 weeks or receive 12 weekly sessions of CBT delivered by a psychotherapist. After treatment, all participants completed the monetary reward task again to assess whether there were changes in neural reactivity related to receiving a reward.
- At baseline, higher levels of depressive symptoms were associated with a more attenuated RewP.
- There were no significant differences between patients and healthy controls in the degree of RewP change across the 12 weeks; however, among patients, the extent of increase in RewP robustly correlated with the extent of decline in depressive and anxiety symptoms following CBT and SSRI treatment.
- A more attenuated RewP at baseline predicted a greater reduction in depressive symptoms following treatment with SSRIs, but not after CBT.
“About 50 percent of people prescribed either selective serotonin reuptake inhibitors, or SSRIs, — a class of antidepressants — or cognitive behavioral therapy get better with those treatments,” said Burkhouse. “We haven’t had an objective way to measure whether a patient is improving with treatment or which patients will do better on SSRIs versus cognitive behavioral therapy, until now.”
“There are serious considerations that go into prescribing either of these treatments,” Burkhouse said. “SSRIs can have unwanted side effects, while CBT requires a significant amount of time and commitment, and practitioners trained in delivering CBT can be hard to find and those that practice this form of therapy may be booked and not able to take on new patients.”
“These findings could help bring precision medicine closer to reality for patients with anxiety and depressive disorders,” said Dr. K. Luan Phan, professor of psychiatry in the UIC College of Medicine and a senior author on the paper.
Many patients who seek treatment for their anxiety and depression don’t always do well with the first therapy prescribed due to not being able to tolerate side effects of drugs or not being able to commit to weeks of talk therapy, said Phan.
“These findings highlight neural responsiveness to reward as both a mechanism and a predictor of depressive symptom change that may be used to serve as an objective index of symptom improvement,” concluded the authors.
For more information click on the link: http://dx.doi.org/10.4088/JCP.17m11836