By Leonora Desar

Many children appear to do surprisingly well in the face of adversity. Close relationships with parents and other caregivers have been found to promote positive development, and certain genes might make kids more sensitive to their environments. But a new study published in Psychological Science suggests that we may be missing the big picture: Even children who seem to beat the odds may be paying a physical price.

"So many of the youth that we studied have a singleminded determination to succeed despite living in the midst of high levels of socioeconomic ," says Gene Brody, lead author of the new study. "The cost might not be detected outwardly by looking at behavior, but all of the effort required to succeed may be exacting a biological toll."

The authors found that the socioeconomically at-risk kids who reported low levels of , conduct problems, and substance abuse and who were rated as highly competent by their teachers in fact showed the greatest signs of physical distress. In other words, the more kids seem to be fighting their way to success, the more their health seems to suffer.

"In the last five to ten years there's been a growing recognition that the vulnerability for these chronic diseases of aging actually have their origins in and ," says Brody. "Scientists including ourselves have begun to ask the question: How does stress that children and adolescents experience get under their skin to create vulnerabilities for the chronic diseases of aging later in life?"

is essential, and children who never learn to face defeat or overcome challenges can struggle socially and psychologically as adults. But Brody's research complicates the picture significantly, suggesting that while developing resilience may be important, it often comes at a price.

"Most people think about resilience as an unmitigated good," says Jay Belsky, a professor in the Human Development and Family Studies Program at the University of California, Davis. "Prevailing ideas say these kids are resilient—they’re coping, they’re succeeding, they’re doing well. What [the study is] showing is that while that is true on the surface, it's not true underneath."

Leonora Desar is an editorial intern at Psychology Today.