New mothers are not the only ones at risk of postpartum depression: A study finds that new fathers with lower testosterone levels are at higher risk of depression. It also finds that these men's hormone levels may help their female partners avoid depression.
Previous research has shown a link between low testosterone levels and depression in men – contributing to feelings of lethargy and disinterest. The new study, published in Hormones and Behavior, measured the testosterone levels of dads when their babies turned 9 months old. Those with lower testosterone levels were more likely to report signs of postpartum depression.
"That fit with our expectations," said Darby Saxbe, a USC assistant professor of psychology who led the study. "What surprised us was actually the flip side for moms. If moms were with lower-testosterone partners, they were actually less depressed."
Even though the men had a higher risk for depressive symptoms, their partners said they were more satisfied in their relationships, and therefore less depressed themselves. The researchers examined data from 149 couples and interviewed them multiple times during the first two years of their babies' lives. High testosterone put men at greater risk of experiencing relationship problems, and moms reported higher levels of partner aggression.
"You're kind of at risk if you're at either end of the spectrum – whether your testosterone was too low or too high," said Saxbe. "It seems like the dads who fared best were somewhere in the middle."
The researchers "really came away from this study thinking testosterone has a really complex relationship with the family," she said.
Ten percent of new fathers – double the rate found among the overall male population – report symptoms of depression, according to a meta-analysis of nearly 30 years of studies published in the Journal of the American Medical Association.
Studies focusing on the animal kingdom have found that among some rodents and primates, new fathers experience dips in testosterone and spend more time with their offspring. This suggests that the hormone may be suppressed during the transition to paternal parenthood.
Saxbe has another study underway at USC to examine testosterone levels both during pregnancy and after birth to examine the change over time.
Postpartum wellness should be seen as an issue for mothers and fathers, she said. Though it's very difficult for new parents, Saxbe said it's important to get enough sleep and exercise, since they're linked to hormone levels and depression.
She also urges policymakers to consider the larger implications of the research.
"[The U.S. is] one of the few societies that not only does not offer really extended maternity leave, but we treat paternity leave like a luxury," said Saxbe. "So I think we really need to think on a policy level about how we can give dads more time off when they have new babies and recognize that that's important for their mental health."