Toronto : Having supportive friends can mitigate the effects of bad experiences and confer psychological benefits.

"Having a best friend present during an unpleasant event has an immediate impact on a child's body and mind," says study co-author William M. Bukowski, psychology professor and director of the Concordia University Centre for Research in Human Development.

"If a child is alone when he or she gets in trouble with a teacher or has an argument with a classmate, we see a measurable increase in cortisol levels (hormone produced by the adrenal gland in response to stress) and decrease in feelings of self-worth," says Bukowski.

"Excessive secretion of cortisol can lead to significant physiological changes, including immune suppression and decreased bone formation. Increased stress can really slow down a child's development," adds Bukowski, the journal Developmental Psychology reports.

A total of 55 boys and 48 girls from grades five and six in local Montreal schools took part in the study. They kept journals on their feelings and experiences over the course of four days and submitted to regular saliva tests that monitored cortisol levels, according to a Concordia statement.

This study is the first to definitively demonstrate that the presence of a friend results in an immediate benefit for the child undergoing a negative experience.

These results have far-reaching implications. "Our physiological and psychological reactions to negative experiences as children impacts us later in life," explains Bukowski.