'In mammals, separation between mother and child after birth has always been considered a major stressor that can cause behavioural problems well into adulthood,' said coauthor Richard E. Tremblay a professor of psychology, pediatrics and psychiatry at the Université de Montréal and director of the Research Unit on Children's Psycho-Social Maladjustment at the Sainte Justine Hospital Research Center.
Our hypothesis was that mother-baby separation resulting from incubator care could heighten depression in adolescence or adulthood.
'Instead, we found that incubator care could decrease the risk of depression two-to-threefold by the age of 21,' he added.
During the study, the researchers examined a subsample of 1212 children recruited from a longitudinal study launched in 1986.
The participants received psychiatric assessments when they were 15 and 21 years old.
They found that of the 16.5 percent babies placed in incubators only 5 percent suffered major depression by age 21.
However, participants, who were not placed in incubators, 9 percent developed depression.
Moreover, girls were three times less likely to experience depression by the age of 15 if they had received incubator care at birth.
Incubators are controlled environments where body temperature, brain oxygenation, sound and light are adjusted to maximize neuronal development.
Children who received incubator care as babies typically received more emotional support from their mothers throughout childhood because they were perceived as more vulnerable.
"Incubator care was not the sole factor that shielded participants from future depression," said first author David Gourion, formerly of the Universite de Montreal and Sainte Justine Hospital Research Centre and now at psychiatrist at the Hopital Sainte-Anne in Paris.
"We believe that incubator care is a trigger for a complex chain of biological and emotional factors that helped decrease depression," he added.
The new study is published in the journal Pyschiatry Research.