New York, March 13 (IANS): Not just mothers but new fathers who are depressed do not make as much eye contact or smile at their toddlers, leading them to develop troubling behaviour such as hitting, lying, anxiety and sadness as they grow, new research has found.

The more disengaged parents are from their child, the greater the risk the child will have forming close attachments and healthy emotions, the team from the Northwestern University noted.

"Father's emotions affect their children. New fathers should be screened and treated for postpartum depression just as we do for mothers," said lead study author Sheehan Fisher.

Depression affects the way people express emotions and it can cause their behaviour to change.

For the study, Fisher collected data from a cohort of nearly 200 couples with three-year-olds.

These couples had participated in a previous depression study around the time of their child's birth.

Fisher found that both maternal and paternal depression levels during toddlerhood were each uniquely associated with child internalising and externalising behaviours.

Parents who reported signs of postpartum depression soon after the birth of their child also showed these signs three years later.

These findings suggest that both maternal and paternal depression in the postpartum period set the stage for future parental depression.

"Fighting between parents did not contribute to children's bad behaviours as much as having a depressed parent did," Fisher noted.

Previous studies have shown that fathers are at a greater risk of depression after the birth of a child than at any other time in a typical male's life.

"Early intervention for both mothers and fathers is the key," Sheehan concluded.

The study was published in the journal Couple and Family Psychology: Research and Practice.