Since the early 1990s, I, together with my colleagues, have been studying the economic burden of adults with major depressive disorders (MDD). Over that time, we have tracked shifts in the prevalence of this disease; in the makeup of those suffering from it; and in the nature of treatment both for the disease itself and for the host of comorbidities, such as pain and anxiety disorders, that accompany it. We have then used these data as the basis for calculating the incremental economic burden of adults with MDD—that is, the additional costs traceable to those suffering from the disease in terms of both medical treatment and workplace productivity impacts.

Our most recent study was just published in a special issue of PharmacoEconomics (which I also co-edited) that presents new research on the economics of MDD. By focusing on one year during the Great Recession (2010) and another after a long macroeconomic expansion (2018), our analysis provides a helpful profile of the changing economic effects of this widespread and pernicious illness. We report our latest estimates showing that the incremental economic burden of adults with MDD was $326 billion in 2018, 38 percent higher than in 2010.

But our work goes deeper than simply providing an economic calculator. This research offers a multifaceted lens through which we can gain a better understanding of how the myriad effects of the illness manifest themselves.

Importantly, we find that only 11 percent of the overall burden of illness was attributable to the direct medical costs of treating MDD itself, while the costs of treating comorbid medical conditions made up 24 percent. Another 4 percent was due to suicide-related costs, while fully 61 percent of the total burden in 2018 resulted from a combination of elevated workplace absenteeism and presenteeism (that is, reduced productivity as a result of working while sick). This striking imbalance between medical expenditures to treat either MDD or its comorbidities on the one hand and workplace-related costs on the other is one aspect of the story that has changed dramatically since 2010, when medical costs were equivalent to workplace costs.

Several other things have also changed meaningfully in the interim. First, the COVID-19 pandemic has so visibly altered our world since early 2020. While the full effects of the pandemic on MDD will not be fully understood for some time, the Centers for Disease Control and Prevention (CDC) estimates the average prevalence to be 27 percent during the pandemic, more than three times its 2019 rate of 7 percent. Of course, it is not yet clear the extent to which this much higher prevalence rate will endure postpandemic. But the unprecedented rise in the number of MDD sufferers seems likely to translate into a higher burden of illness, even though its precise magnitude and composition will not be known for some time.

A second significant change that we document in our latest study is that the prevalence of illness now includes many more younger people than ever before. Of the 15.5 million MDD sufferers in 2010, 5.4 million (35 percent) were between 18 and 34 years of age. In contrast, there were 17.5 million people who suffered from MDD in 2018, 8.3 million (47 percent) of whom were in this younger age cohort. This shift to a younger age mix likely results in added burdens at work, home, and school. Since the age of onset usually occurs by the time an MDD sufferer is a young adult, without effective and timely intervention, these individuals are especially vulnerable to potentially irreversible adverse life outcomes, including dropout from high school or college, teenage parenting, and marital or job instability.

A third key trend relates to the deceleration in the MDD treatment rate we have seen over time. Although it doubled from 28 percent in 1990 to 56 percent in 2018, the treatment rate has hovered near its current level for the past 15 years. With 44 percent of MDD sufferers not reached at all by the health care sector, there still exists a substantial unmet treatment need. If broader outreach and more effective forms of care can help shift more of the direct medical expenditures to treatment of MDD itself rather than treatment of comorbid physical and psychiatric conditions, such a change would be wholly welcome.

A fourth important trend we observe focuses on more favorable employment conditions in 2018 compared to 2010. Throughout the business cycle, labor force attachment tends to be far more volatile for people with MDD. While they are highly employable especially in economically robust times, MDD sufferers are often disproportionately adversely affected during economic declines (particularly those aged 50-plus).

One recurring insight from our body of research is that there is a complex interaction among MDD prevalence, severity, treatment and employment rates through the business cycle.  As a result of this dynamic, there is an inherent tension between societal interests and individual employer interests in terms of who bears the costs of optimal MDD-patient management. This represents a continual challenge even during the best of macroeconomic conditions.

In general, the economic burden of an illness is related to how widespread it is in society, how debilitating it is in terms of resulting impairment among sufferers, and how widely treated it is in the medical sector. Our updated research findings continue to add to our understanding of the burden of illness. But with the effects of the pandemic on MDD still not yet clear, it will take several years to amass relevant data that can shine a bright light on many of these complicated dynamics.

This is an opinion and analysis article.