Previous studies have shown that during adolescence, rates of depression increase markedly, and girls tend to have rates of depression twice as high as boys. Depressed adults were also shown to exhibit a decreased behavioral response to a reward and less brain activity in regions associated with reward processing in comparison to healthy adults. Dr. Brady Nelson and his team of researchers from Stony Brook University researched this correlation in adolescent girls.
The researchers tested whether a positive reaction to a reward was predictive of first-onset depression and a higher degree of depressive symptoms 18 months later in adolescent girls. It was hypothesized that a smaller positive reaction to a reward would indicate a higher likelihood of first-onset depression and more severe symptoms at a follow-up in 18 months. The study involved adolescent girls aged 13.5-15.5 with one biological parent (N=444). The Kiddie Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version assessed psychiatric history and possible diagnosis changes before at baseline and follow-up. The Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, 4th Edition Axis I Disorders assessed the parental psychiatric history.
Participants underwent an electroencephalogram scan to detect electrical activity in the brain while presented with the Doors task. In this task, two doors were shown on a screen, and participants were instructed to pick one door to open. When opened, the participant would see a green arrow pointing upwards, indicating a $0.50 reward, or a red arrow pointing downwards, indicating a $0.25 loss.
At the 18-month follow-up, 9.0% of teen participants had experienced a first-onset depressive disorder. For those who had experienced a first episode, in comparison to those who had not, dysphoria symptoms were greater at baseline (p<0.001) and the follow-up (p<0.001). A greater likelihood of developing a first-onset depressive disorder was correlated with a smaller reaction to reward positivity (p<0.01) independent of parental psychiatric history. Unlike other studies, this study looks at a new demographic. In future studies, other populations should be analyzed, as the population of girls aged 13.5-15.5 is not generalizable to a large population of people.
- B. Nelson et al., Blunted neural response to rewards as a prospective predictor of the development of depression in adolescent girls. The American Journal of Psychiatry 173, 1223-1230 (2016). doi: 10.1176/appi.ajp.2016.15121524.
- Image retrieved from: https://pixabay.com/en/desperate-sad-depressed-cry-2057116/