Summary: Study reports that almost 30% of women and 17% of men experience major depressive episodes over the course of their lives.
The number of adults in the United States who suffer from major depressive episodes at some point in their life is far higher than previously believed, a new study by the Yale School of Public Health finds.
National survey data currently shows that approximately 17% of women and 10% of men report having a history of major depressive episodes (MDEs) in their lifetimes. But these data are subject to “recall error,” or the tendency of people to forget or misreport their health histories when taking a survey.
Researchers led by Jamie Tam, Ph.D., assistant professor in the Department of Health Policy and Management, created a simulation model to generate corrected estimates of lifetime depression. They found that the proportion of U.S. adults who have had MDEs is actually closer to 30% of women and 17% of men after factoring in recall error.
“Major depressive episodes are far more common than we thought,” said Tam. “Our model shows that the probability of someone having a first major depressive episode is especially high during adolescence. We also know from other research that having a first major depressive episode increases the likelihood you’ll have a second one. This means that anything we can do to prevent or treat episodes among young people could lead to larger health benefits over the course of their life.”
The findings are published in the American Journal of Preventive Medicine.
A major depressive episode is defined as a period of two weeks or longer in which a person experiences feelings of intense sadness and hopelessness, fatigue, weight gain or weight loss, changes in sleeping habits, loss of interest in activities and thoughts of suicide or attempts at suicide. These persistent symptoms cannot be easily changed, even if they are contradictory to a person’s circumstances. Depressive episodes typically recur periodically in people diagnosed with major depression.
The study shows that mental health programs that screen for, prevent and treat depression could benefit a much larger segment of the population than previously thought, Tam said.
“If you think about chronic health conditions like heart disease, we do a lot to identify people who might be at risk for additional health events like heart attacks because that group would benefit from maintenance treatment and clinical monitoring,” Tam said. “We don’t do such a great job when it comes to mental health conditions. So, if we’re able to assess how many people actually have histories of depression, that also tells us that more people are at risk of experiencing more depressive episodes.”
The researchers also found that older adults are especially likely to under-report their history of having depressive symptoms. Among adults 65 years and older, underreporting for depression was as high as 70%. Older adults often experience what is referred to as “minor depression,” where they still report significant depressive symptoms but don’t always meet clinical requirements for major depression. Tam said there may be a tendency for older adults to downplay negative experiences of depression from when they were younger, classifying them as “growing pains” rather than major depression.
“Unfortunately, many people with depression or with histories of depression don’t access, or don’t have access to, treatment or support,” Tam said. “There’s a broader problem in our society of mental health not receiving the same attention and investment of resources compared to physical health conditions.”
Tam wrote the paper with colleagues from the University of Michigan School of Public Health.
About this depression research article
Source: Yale Media Contacts: Michael Greenwood – Yale Image Source: The image is in the public domain.
U.S. Simulation of Lifetime Major Depressive Episode Prevalence and Recall Error
Introduction Simulation models can improve measurement and understanding of mental health conditions in the population. Major depressive episodes are a common and leading cause of disability but are subject to substantial recall bias in survey assessments. This study illustrates the application of a simulation model to quantify the full burden of major depressive episodes on population health in the U.S.
Methods A compartmental model of major depressive episodes that explicitly simulates individuals’ under-reporting of past episodes was developed and calibrated to 2005–2017 National Surveys on Drug Use and Health data. Parameters for incidence of a first major depressive episode and the probability of under-reporting past episodes were estimated. Analysis was conducted from 2017 to 2019.
Results The model estimated that 30.1% of women (95% range: 29.0%–32.5%) and 17.4% of men (95% range: 16.7%–18.8%) have lifetime histories of a major depressive episode after adjusting for recall error. Among all adults, 13.1% of women (95% range: 8.1%–16.5%) and 6.6% of men (95% range: 4.0%–8.3%) failed to report a past major depressive episode. Under-reporting of a major depressive episode history in adults aged >65 years was estimated to be 70%.
Conclusions Simulation models can address knowledge gaps in disease epidemiology and prevention and improve surveillance efforts. This model quantifies the under-reporting of major depressive episodes and provides parameter estimates for future research. After adjusting for under-reporting, 23.9% of adults have a lifetime history of major depressive episodes, which is much higher than based on self-report alone (14.0%). Far more adults would benefit from depression prevention strategies than what survey estimates suggest.