Persson and Rossin-Slater said they were initially inspired by two recent economic studies using data from Uganda and Iraq, which found that fetal exposure to malnutrition had adverse consequences for adult mental illness.
They wrote: “Our study offers complementary evidence linking early-life circumstance to adult mental health, but breaks new ground by focusing on stress, which may be more pertinent than malnutrition in modern developed countries such as the United States and Sweden, and by tracing health outcomes throughout the time period between the fetal shock and adulthood.”
Mental illness results in great financial and social costs. In 2008, the market for prescription drugs for depression totaled $9.6 billion in the United States alone, a sales volume exceeded only by cholesterol and pain medications.
In 2013, 1 in 7 school-age boys in the United States were treated with prescription drugs for attention deficit hyperactivity disorder, fueling a $9 billion market — five times larger than the $1.7 billion market just a decade earlier. The authors note that estimates also suggest mental illness accounts for more than half of the rise in disability costs among men in the last two decades.
Moreover, in Sweden — the setting for their study — mental illness accounts for a larger share of health expenditures on prescription drugs than any other therapeutic class of medicines.
The scholars said their study contributes to the research in this area by documenting a causal link between fetal stress exposure and mental health later in life. Moreover, by following the same children from birth to adulthood, they were able to observe the onset of adverse effects of exposure to maternal bereavement in utero.
“In sum, our results show that the death of a relative up to three generations apart during pregnancy has far-reaching consequences for mental health during childhood and adulthood,” the researchers write.
Their findings indicate that preventing fetal exposure to severe stress could result in large welfare gains: For example, based on the 2008 figure for the U.S. market, the 8 percent decrease in the consumption of prescription drugs for depression can be valued at around $800 million annually.
They conducted a back-of-the-envelope calculation to understand how exposure to economically induced stress during pregnancy might affect the mental well-being of the next generation by relying on past research estimating cortisol responses to grief and to economic shocks like unemployment and poverty.
“Our calculation suggests that in utero exposure to stress from unemployment may lead to a 17.3 percent increase in the likelihood of ever purchasing a drug to treat ADHD in middle childhood,” they wrote, “and a 9 percent and 5.5 percent increases in the likelihoods of ever purchasing drugs to treat anxiety and depression in adulthood, respectively.”
The newly published findings can inform one way by which policymakers and the medical community can tackle the prevalence and rising costs of mental health issues: by considering ways to make pregnancy — an inherently stressful time — a little easier to manage.
Rossin-Slater and Persson are both fellows at the at the Stanford Institute for Economic Policy and Research.
The research was supported by the Royal Swedish Academy of Sciences and by the Jan Wallander and Tom Hedelius Foundation.