Did prehistoric mothers suffer from postpartum depression?
Jennifer Hahn-Holbrook, a psychology professor at Chapman University in Orange, Calif., has been researching whether the condition can be considered a so-called disease of modern civilization such as obesity and Type 2 diabetes.
Hahn-Holbrook and Martie Haselton of UCLA wrote a paper examining the connection between postpartum depression rates and lifestyle factors that differ significantly from earlier eras.
They note that hunter-gatherer women breast-fed for several years, had consistent exposure to vitamin D through sunshine and lived among extended family. Additionally, they would have exercised more and eaten diets rich in omega-3 fatty acids from wild organ meat, both of which have been linked to lower rates of depression.
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Hahn-Holbrook also recently gave birth to her first child and is on maternity leave from Chapman.
The exact causes of postpartum depression are unknown, but medical experts note that changes in hormone levels may influence mood. Changes in work and relationships, a reduction in leisure time and freedom, lack of sleep and worries about motherhood may also play a role.
In addition to typical depressive symptoms, postpartum depression may include feeling numb or disconnected from the baby; having scary or negative thoughts, including fear of harming the baby; and feeling guilty about not being a good mother, according to the Centers for Disease Control and Prevention.
Postpartum depression varies from the so-called baby blues, which commonly include mood swings and teariness but don’t last longer than two weeks.
Hahn-Holbrook said postpartum depression rates vary around the world, suggesting that societal factors play a role.
For instance, breast-feeding rates are much lower than they were for most of human history, with roughly 20 percent of American mothers never trying it. The paper notes that prehistoric fossils indicate that infants were weaned between ages 2 and 4.
Hahn-Holbrook runs a breast-feeding research lab where she’s found that breast-feeding mothers experience less stress than other women. Additionally, other studies have shown that nursing mothers are less likely to be depressed.
“I think evolution built in some mental health effects,” she said. “By not doing that, I think some women aren’t getting their postpartum stress buffer.”
Lack of communal support is also a big challenge for many new mothers, which could be contributing to depression rates, she said.
“Somebody to hold the baby while you take a shower is the difference between sanity or not,” she said. “I live 1,000 miles away from my nearest blood relative, and it is not easy. We’re what we call cooperative breeders. Human children are the most labor-intensive mammals.”
The paper also explores vitamin D, which has anti-inflammatory properties. Some studies have linked deficiency to depression.
“What I don’t want readers to walk away with is that everything old and natural is good and everything that is new and modern is bad,” Hahn-Holbrook said. “As modern women, we’re trying to design workarounds. I’m not going to spend three hours a day in the sun; I’m going to take a vitamin D supplement. Maybe I don’t need to be around my baby 24 hours a day for six months; maybe I can pump (breast milk) and still go to work.”