Depression in a parent—particularly a mother—is likely to induce stress in children, a new study says. Researchers from the University of Maryland and Stony Brook University measured levels of the stress hormone cortisol in 3-year-old children after subjecting them to harmless but stress inducing situations. In addition, researchers also observed the children with a parent performing a task together, such as reading a book, noting their interactions.

The children with the largest stress responses were those whose mothers had suffered from depression at some point in the child's life, as well as those whose mothers displayed some form of hostility—voiced anger, frustration, or critical comments--when playing with the children.

The study did not include enough fathers to aptly measure their or the children's responses. In addition, depression was less common in fathers.  The study, which is due for publication in the journal Psychological Science, highlights the role of stress in depression. According to the authors, a parent's depression can lead to depression in a child.

Still, lead researcher Mary Dougherty says the findings are "actually quite hopeful, because, if we focus on the parenting, we could really intervene early and help parents with chronic depression when they have kids.”