Neural Responses to Positive and Negative Events Moderate Depression Risk

Katherine Luking, PhD

The robustness of neural responses to positive and negative events may modify adolescent girls’ risk of depression, according to a new study.

Investigators have observed that negative life experiences can increase risk for depression while positive ones can decrease this risk. However, there are some individuals who experience substantial negative life events and do not go on to develop depressive symptoms. Researchers at Stony Brook University wondered if neural responses to life events might underlie this difference in outcome.

“In the past 15 years or so there has been a strong shift in the adolescent depression literature to focus on the role of blunted responding to reward in disorder onset and maintenance,” said Katherine Luking, PhD, a postdoctoral fellow in psychology at the University of Stony Brook and lead author of the study. “This work goes beyond reward and suggests that how the brain responds to losses is another important component of adolescent depression.”

She and her team asked 130 girls aged 8 to 14 to complete a survey known as the Child Depression Inventory. They asked the girls’ parents to answer questions about whether the girls had recently experienced certain events and whether the parents believed that these events had been positive or negative for the girls. These events were also separate based on whether they were directly related to the girls’ behavior (such as getting a good grade on a report) or unrelated to the girls’ behavior (such as a family moving into a new home or experiencing a natural disaster).

Lastly, the girls were placed in an fMRI scanner. While inside, they were asked repeatedly to choose between 2 doors. If they chose the “correct” door, they won $0.50. If they chose the wrong door, they lost $0.25. The researchers measured ventral striatal activity when the girls won compared to when the girls lost.

They found that ventral striatal response to reward was associated with a greater beneficial effect of positive experiences on preventing depressive symptoms. A stronger ventral striatal response to loss increased the adverse effect of negative life events on depressive symptoms. Each response acted independently of the other.

“Findings suggest that targeting neural responses, ie. increasing response to winning or decreasing responses to losing, may be important for both improving resilience and reducing risk in different environmental contexts,” wrote the researchers.

The researchers also hypothesized that there would be a difference in the effects based on whether or not the girls had control over the experiences. Those with more powerful responses to winning also experienced more protective effects when positive experiences were dependent on their behavior, while those with more powerful responses to losing experienced more detrimental effects when the experiences were beyond their control.

“I hope this will encourage researchers and clinicians to think about the brain’s response to rewards and losses as two unique components of depression-risk rather than the opposite sides of the same coin. This would mean treating both pieces,” said Luking.

Next, the researchers hope to investigate the relationships of neural responses to positive and negative experiences in younger children to better understand the timing of these interactions.

“Ultimately we would like to be able to identify individuals at high risk for future depression early in development as preventative interventions are likely to be more effective than intervening after adolescents have experienced depression,” explained Luking.

The study, “Ventral Striatal Function Interacts with Positive and Negative Life Events to Predict Concurrent Youth Depressive Symptoms,” was published in Biological Psychiatry.