Children of bipolar parents are overly sensitive to stress hormone cortisol, study finds

"Previous research has shown that children of parents with bipolar disorder are four times as likely to develop mood disorders as those from parents without the condition," says senior author Mark Ellenbogen, Canada Research Chair in Developmental Psychopathology at Concordia University and a member of the Centre for Research in Human Development. "The goal of our study was to determine how this is happening."

Cortisol, the telltale hormone

Ellenbogen and colleagues had previously shown that cortisol levels in children with a parent affected by bipolar disorder were higher than kids whose parents were unaffected by the condition. The current study measured cortisol levels in these same individuals during chronic and episodic stress periods. In both circumstances, children of parents with bipolar disorder showed a greater increase in cortisol than those of parents without the disorder.

"Our study demonstrates that affected children are biologically more sensitive to the experience of stress in their natural and normal environment compared to unaffected peers," says Ellenbogen. "This higher reactivity to stress might be one explanation of why these offspring end up developing disorders and is a clear risk factor to becoming ill later on."

"We think we might be beginning to understand where we can intervene to actually prevent this increased sensitivity from developing," continues Ellenbogen. "We believe this sensitivity develops during childhood and our suspicion is that if you could teach both parents and their offspring on how to cope with stress, how to deal with problems before they turn into larger significant stressors and difficulties, this would have a profound impact."

About cortisol: Cortisol is a hormone that is produced by the body in response to anxiety and researchers use cortisol to monitor the biological response to stress.

About bipolar disorder: Bipolar disorder, which is also known as manic depression, is a treatable illness marked by extreme changes in mood, thought, energy and behavior. Bipolar disorder is also known as manic depression because a person's mood can alternate between mania (highs) and depression (lows). These changes in mood, or "mood swings," can last for hours, days, weeks or months.

This work was supported by the Canadian Institutes of Health Research, the Social Sciences and Humanities Research Council of Canada and the Fonds du Québec en Recherche sur la Société de la Culture.