TEL AVIV, Israel, Dec. 11 (UPI) — Children whose mothers were depressed throughout their first year of life have a higher risk of mental disorders themselves by age 6, researchers in Israel say.

Ruth Feldman, a professor at Bar-Ilan University in Israel, found 60 percent of children born to mothers who were consistently depressed across the first year of the children’s lives exhibited mental disorders when they were older. The children, similar to their mothers, also showed disordered functioning of the Oxytocin system.

Oxytocin, a mammalian hormone, is involved with sexual reproduction, childbirth, breastfeeding and pair bonding.

Researchers studied the mental health status, Oxytocin levels, genetic variation in Oxytocin receptors and interactions in 155 mother-child pairs during at-home visits. The mothers were surveyed for mental health symptoms at the birth of their child, and at 6 and 9 months after the birth of their child.

Of the pairs participating when the child reached 6 years of age, 30 percent of mothers were diagnosed with depression and had demonstrated symptoms of depression throughout the child’s first year of life. On average, these mothers had disordered Oxytocin functioning and produced less peripheral Oxytocin in their saliva.

Most children born to depressed mothers exhibited mental disorders, but 40 percent demonstrated more normal functioning of the Oxytocin system, no signs of mental illness, better social engagements and empathic behaviors.

“We found Oxytocin system functioning helps safeguard some children against the effects of chronic maternal depression,” Feldman said.

The findings were presented at the American College of Neuropsychopharmacology annual meeting.