Maltreatment or abuse may cause stress-triggered reactions in children that can push them into worsening levels of depression, according to a study published by Canadian researchers this year.
The study involved just 71 youths and young adults, all of whom were given a formal stress test. Researchers then measured the amount of cortisol – a hormone released by the body as a result of stress – each participant secreted.
The mildly depressed abuse victims had a stronger reaction to the stress test than other participants. Severely depressed abuse victims had no reaction to the stress test.
Study co-author Kate Harkness of the Queen’s University in Ontario said the results suggest that the “trauma of abuse is leading to, in the short term, an over-release of cortisol,” which is “toxic to the brain.”
As for the severely depressed victims, Harkness said, the findings suggest that they are “beyond the point of trying to feel anything.”
“What we’re trying to prove is that childhood maltreatment causes depression by causing these changes in the brain, the disruption of this stress response system,” Harkness said. She said the finding challenges the assumption made my most people that “you are born with a brain and that is your brain for life.”
The findings echo patterns in stress reactions that have been studied and documented in adults, Harkness said, especially soldiers returning from combat with Post Traumatic Stress Disorder.
The results suggest that cortisol secretion might be used by medical professionals to indicate the severity of an abused child’s depression, but Harkness said she would not encourage that.
“It’s probably too early … to use cortisol as a diagnostic test,” she said. “It’s still better to work forward to a diagnosis.”
The study recommends that similar research be done on a larger sample and include “a higher number of healthy adolescents with maltreatment histories.”
“Cortisol reactivity to social stress in adolescents: Role of depression severity and child maltreatment” was published in the February 2011 edition of the journal Psychoneuroendocrinology; click here to access the journal. 9 pages.