KINGSTON, Ontario, April 25 (UPI) -- Physical, sexual or emotional abuse in childhood increases the risk of depression in teens by altering a person's response to stress, Canadian researchers say.
Kate Harkness of Queen's University in Kingston, Ontario, says adolescents with a history of maltreatment and a mild level of depression were found to release much more of the stress hormone cortisol than is normal in response to psychological stressors such as giving a speech or solving a difficult arithmetic test.
"This kind of reaction is a problem because cortisol kills cells in areas of the brain that control memory and emotion regulation," Harkness says in a statement.
"Over time, cortisol levels can build up and increase a person's risk for more severe endocrine impairment and more severe depression."
Harkness and colleagues say youths with a history of maltreatment had a total blunting of the endocrine response to stress suggesting that the normal operation of the stress response system can break down in severely depressed adolescents.
These results are important because they show that environmental stress in childhood changes the function of the brain in ways that may cause and/or maintain severe psychiatric disorders such as depression, Harkness says.
Harkness presented her findings at the International Society for Affective Disorders Conference in Toronto.
