Note: The views expressed in this blog poster are those of the authors and do not necessarily reflect the position or policy of the U.S. Department of Veterans Affairs or the United States government.

If you were present at some point in the last six years, chances are high that you or someone you know had COVID-19 at some point. When you think about that illness, you probably remember the worst fever you ever had, the sudden shortness of breath, and relentless cough that kept you up at night. COVID-19, a new respiratory illness at the time, had come to be defined by the old hallmark symptoms of respiratory viral infections—if not more severe. Several months into the pandemic, as the number of survivors of the illness increased, we began to hear reports about prolonged physical symptoms as well as cognitive and mental health symptoms like depression and anxiety. This was new. “Long COVID” was later coined to describe the ongoing symptoms many illness survivors experienced, and the mental health effects are what motivated our team do this study.  

“At the time,” Dr. Jason Chen, lead author on our study, recalls, “there were so many news stories and reports about mental health conditions following COVID-19 but not much systematic research.” He could see how the anecdotal stories and lack of research were fueling anxiety for him and his patients. To him, this study was an opportunity to better understand and quantify whether COVID-19 was really causing mental health symptoms. Or not. This was a really tricky research question to answer, because social distancing policies, shutdowns, and the economic downturn likely increased isolation and stress—could that be why people were reporting more depression?  

Dr. David Bui, co-author on the study who worked in public health research prior to coming to the VA, recalls finding post-pandemic increases in depression rates and unmet mental health needs in large representative survey studies. “My takeaway from that early research was that the pandemic certainly affected mental health, but I had no idea that infection itself could have long-term mental health effects,” he says.  

To understand how infection may affect mental health, you needed to survey people with COVID-19 and ask them about symptoms long after their infection. There were very few COVID-19 studies that asked patients about symptoms they experienced and even fewer that follow up over a long period of time. This is why our study is so important—we attempted to separate the effect of the pandemic from the effect of infection and found surprising results.  

In this study, our team surveyed Veterans in the VHA who had COVID-19 during the first year of the pandemic and had them complete the PHQ-9 about 18-months later. We then surveyed similar Veterans who did not have COVID-19 at that time. This helped us control pandemic level effects (since everyone was affected by the pandemic) and isolate infection effects.  

Compared with similar Veterans who did not have COVID-19, we found that those with COVID-19 reported more frequent depressive symptoms, even 18 months after their infection. Notably, we found that mood symptoms were much higher in those with COVID-19 compared with physical depression symptoms. “I was also impressed to see how far out after COVID infection these symptoms were elevated, though we didn’t have much information on what could be contributing to them,” says Chen.  

Although the effect sizes we found appeared small, the real-world implications to the VHA population are actually staggering. We found the absolute risk increase in screening positive for depression among Veterans with COVID-19 within 18 months was about +22%. Given that >850,000 Veterans have had a documented case of COVID-19, we could expect tens of thousands of new cases of depression, resulting in hundreds of thousands of depression-related visits. This suggests we may need to prepare for an influx in Veterans needing help with depression in the VA. This is an example where small research effects could have large public health implications for health systems.  

Our results highlight the need to ensure access to mental health services for Veterans after the pandemic, particularly given the long-term risk of depression and other mental health concerns. Expanding access and use of mental health care may help decrease challenges from these depressive symptoms. Despite declines in mortality and hospitalization risks, COVID-19 remains a serious infectious disease. Prevention is still important—that means washing hands, getting vaccinated, wearing a mask if ill.  

Patients with COVID-19 who are dealing with mental health conditions, should seek care if they begin to develop depressive symptoms and understand the effect that infectious diseases can have on mental health. “Our findings remind me of the importance of ensuring we pay proper attention to when patients report depression symptoms that are continuing after COVID and other infections,” says Chen. “Sometimes, there can be a tendency to think of things as purely situational, but when symptoms continue for a while, I think that calls to my mind a need to do a deeper dive into what might be going on.”