University of Illinois psychology professor Eva Telzer, who led the research, said that there's this trend where from childhood to adolescence, morbidity and mortality rates increase 200 to 300 percent, and it's almost entirely due to these preventable risk-taking behaviors.
Using a functional brain scan, the researchers measured ventral striatum activity in adolescents who engaged in tasks that involved either giving money to others, keeping the money or making risky financial decisions in the hope of earning a reward. The team tested the subjects' depressive symptoms initially and at the end of a year.
The researchers found that activity in the ventral striatum in response to different rewards predicted whether the subjects' depressive symptoms would worsen - or lessen - over time.
Telzer, who also is a professor in the Beckman Institute at Illinois, said if they show higher levels of reward activation in the ventral striatum in the context of the risk-taking task, they show increases in depressive symptoms over time.
She said that if they show higher reward activation in the pro-social context, they show declines in depression.
The scientists have been published in the Proceedings of the National Academy of Sciences.