Talk therapy for new mothers with postpartum depression may also benefit their babies' brains, Canadian researchers say.

"We found that after their moms were treated that their infant's brain activity normalized to the levels seen in our healthy infants," said study co-author Ryan Van Lieshout, an associate professor of psychiatry and behavioral neuroscience at McMaster University in Hamilton, Ontario.

The study included 40 infants of women with postpartum depression and 40 infants of non-depressed mothers. The mothers with postpartum depression received nine weeks of group cognitive behavioral therapy. This type of therapy aims to help patients change destructive thought patterns.

Their infants were assessed before therapy began and nine weeks later. That included having mothers and their partners complete a questionnaire on their infants' behavior.

Cognitive behavioral therapy not only helped the mothers, but also led to improvements in their infants' nervous and cardiovascular systems, as well as their emotions and behavior, according to the researchers.

It is known that children of women with postpartum depression have changes in brain function that increase their risk of emotional and behavioral problems later in life, but it wasn't known if treating the mother's postpartum depression could reduce the risk.

"We believe that this is the first time that anyone has shown that treating moms' postpartum depression can lead to healthy changes in the physiology of the brains of their infants, a finding that we think provides a lot of good news," Van Lieshout said in a university news release.

"This study shows that cognitive behavioral therapy, a treatment that is short, cost-effective, and preferred by women, could potentially reduce the intergenerational transmission of risk from mother to child," he added.

The study was published recently in the journal Depression and Anxiety.