More than 264 million people experience depression worldwide. In the United States alone, more than 17 million adults experience depression each year. And women, especially those who are currently or recently pregnant, are at higher risk for a depressive episode. As such, regular depression screenings for women during and after pregnancy is a recommended practice, and doctors may want to continue screening women throughout their lives. Consistent measurement of depression throughout a woman’s lifetime can be difficult because the measurement tools used around pregnancy are scored differently from the common measures of adult depression. Linking these measurement tools together will help doctors track the changes in depression across a woman’s lifetime.
To address this research gap, Courtney K. Blackwell, PhD, and her ECHO colleagues conducted a study aimed at linking the Edinburgh Postnatal Depression Scale (EPDS)—a measure of depression in women during or after pregnancy—with the Patient-Reported Outcomes Measurement Information System Depression (PROMIS-D), a general measure of adult depression.
This study included approximately 1,200 mothers from two ECHO sites in the Northern Plains of the US who each completed the EPDS and PROMIS-D surveys. All data were collected using an online survey. Most of the participants were white, but the sample also included American Indian/Alaska Natives. On average, the participants were 35 years old, and about half had a 4-year college degree or higher.
While the EPDS includes more specific measures of postpartum depression symptoms, the study found that the EPDS and PROMIS-D gave depression scores that were highly correlated for women around pregnancy. Both surveys asked questions about increased depressed mood and decreased interest and engagement in daily activities. The researchers were able to convert EPDS scores to PROMIS-D scores for consistent tracking of depression in women throughout adulthood. The converted scores held for different ages, ethnicities, races, and study sites.
“To know about someone’s depression across time, it is important to have a way to use data from different measures that may have been used at different timepoints,” said Blackwell. “This study provides a way to convert scores from a measure used during and after pregnancy to a measure that is used at any time in adulthood.”
The conversion table may also be useful to ECHO researchers who want to standardize depression measurements from multiple cohort sites. Additional studies may examine how different depression measures can be converted using similar methods.
The conversion table is available on prosettastone.org.