Blunted neural response to rewards predicts depression in adolescents

New research shows that a reduced neural response to receiving rewards in adolescents predicts the first onset of depression, but not anxiety or suicide. This is independent of pre-existing symptoms of depression or anxiety, as well as age or gender, which are already strong risk factors for depression. The study in Biological Psychiatry: Cognitive Neuroscience and Neuroimagingpublished by Elsevier, is a step towards using brain science to understand and assess mental health risks.

Mood and anxiety disorders among young people are a growing concern and have long-lasting consequences. Very few studies have identified premorbid neural markers that indicate the risk of developing these disorders in an adolescent’s lifetime. This is especially important given that 50% of children who experience one episode of depression or anxiety will go on to experience a second one. Among those who have had two episodes, 80% will go on to have a third or more.

Researchers at the University of Calgary, Alberta, Canada, followed a group of 145 teenagers (64.8% female) with a family history of depressive or anxiety disorders, which put them at very high risk of developing these disorders themselves. Participating families were part of the Calgary Biopsychosocial Risk for Adolescent Internalizing Disorders (CBRAID) study, a longitudinal research project examining premorbid risk factors for first-onset mood and anxiety disorders in adolescence.

The researchers conducted nine- and 18-month follow-ups to assess whether the participants had developed major depressive disorder, anxiety disorder, or suicidal ideation. They found that a blunted response to reward feedback (also known as a positive reward) while playing a game during an EEG scan in which the teens were told they either won or lost predicted first onset depression, but not anxiety or suicide. This may suggest that adolescents who feel less pleasure or satisfaction when receiving rewards are particularly vulnerable to developing depression for the first time in their lives.

First author Gia-Huy L. Hoang, a second-year master’s student in neuroscience at the University of Calgary, adds, “Evidence shows that children with depressive or anxiety disorders, which often co-occur, generally show a blunted response to rewards. Our research suggests that the brain’s response to rewards may be an indicator that specifically indicates risk for depression, rather than anxiety or suicide, in adolescents Using EEG to measure how the brain responds to rewards is a simple and low-cost method of measuring this response.

Its editor-in-chief Biological Psychiatry: Cognitive Neuroscience and Neuroimaging Cameron S. Carter, MD, University of California Irvine, comments, “Depression, anxiety, and suicide are closely related and highly disabling and common problems that typically begin during adolescence. Reward processing is closely related to depression and anxiety. However, little is known about whether a blunted response to rewards precedes these conditions and carries risk for depression, anxiety, or suicide Research for specific biomarkers that can identify early life risk Occurrence of these conditions is extremely important to understand and the assessment of mental health risks”.

Senior researcher Daniel C. Kopala-Sibley, PhD, Hotchkiss Brain Institute, Alberta Children Hospital Research Institute, The Mathison Center for Mental Health Research & Education, and Department of Psychiatry, Cumming School of Medicine, University of Calgary, concludes, “Our findings are important as we work to understand the brain underpinnings of why adolescents experience depression for the first time in their lives, which may ultimately enhance our ability to identify those at risk and intervene with them to prevent appearance of these disorders.”