Why Is Depression a High-Risk Factor for COVID-19?

Living through the COVID-19 pandemic has given scientists lots of new facts about the coronavirus SARS-CoV-2 causing it. However, the risk of getting this disease depends not only on close contact with the virus carrier. Many various factors affect this probability. Among them are age, sex, living conditions, the immune system, obesity, etc. Our mental health is also a key factor influencing our ability to resist diseases of an infectious nature. Some conditions like depression can impact people’s struggles with COVID-19 directly or indirectly, which we explore in this article. That’s why caring about one’s psychological health is as important as about their physical health.

Is Depression a High-Risk Factor for COVID-19?

Studies find a connection between depression and COVID-19. It concerns the risks of getting the infection, the severity of the symptoms, and the disease consequences. People with COVID-19 and depressive disorder have a higher risk of hospitalization and mortality. [1] This situation can worsen if individuals suffer from comorbid mental issues, like, for example, ADHD or anxiety disorder. Therefore, depression should be considered carefully in COVID-19 treatment. [2]

The Link Between Depression and COVID-19 Risk

COVID and depression risk factor is bilateral. Depression inhibits the immune system, increasing the risk of catching a disease, particularly coronavirus. Moreover, genetic susceptibility to psychiatric disorders correlates with an increased risk of severe COVID-19 outcomes. [3] Conversely, coronavirus disease can cause depression, especially in those with pre-existing mental health conditions. The link between depression and COVID-19 is strengthened by many factors, such as affected immunity, behavioral factors, post-infection consequences, isolation of COVID-sufferers, etc.

How Depression Affects the Immune System?

Researchers discovered that depression weakens immunity. [4] The influence of this mental condition is much more complex than just emotional. It can manifest through the following factors:

• Hormonal and neurotransmitter effects. Depression overactivates the hypothalamic-pituitary-adrenal (HPA) axis, increasing cortisol levels. This steroid hormone suppresses immune function, enhancing the chance of contracting an infectious disease. [4]
• Immune cell dysfunction. Cortisol and other stress hormones deform white blood cells, aggravating their performance of protecting the body from infections. Depression also can correlate with impairing Natural Killer (NK) cell function and even a hyperactive immune response. [5]
• Bidirectional relationship between the immune system and depression. Prolonged immune activation because of chronic illness, for example, can lead to depressive conditions. At the same time, depression weakens immune defenses, opening access to infections. Anyway, depression and COVID risk increases, which emphasizes the value of proper depressive treatment.
• Chronic inflammation and depression. Studies revealed the link between them having similar physiological pathways. The same biomarkers can be found in those with depression and inflammation. [6]

Behavioral Factors That Increase Risk

Depression not only impacts the immune system on hormonal and neurological levels.  It leads to changing behavioral patterns, which enhance the risks of getting ill with COVID-19. Habits of depressed people also indirectly affect their ability to resist infections.

• Reduced adherence to preventive measures. Persons with depression tend to have lower motivation and apathy in everyday life. It also concerns following public health guidelines like masking, vaccination, or timely visits to the doctor due to first-appearing symptoms.
• Social withdrawal. Though social isolation is considered a first-line measure against COVID, avoidance of social contact practiced by depressed sufferers can lead to loneliness and lack of support. Loneliness itself can contribute to immune dysfunction. [7]
• Substance use. Prolonged depression enhances the likelihood of smoking and alcohol consumption. [8] These unhealthy habits suppress the immune system, and smoking also impairs lung function.
• Poor sleep and diet. Sleep problems and unhealthy eating habits are common in depression and significantly worsen the organism’s resistance to infections.
• Cognitive impairment. Depression strongly affects the cognitive skills of sufferers, which may lead to poor decisions and reduced awareness about their health condition. Such people can delay testing or ignore symptoms, for instance.

Depression and Long COVID

Post-acute sequelae of SARS-CoV-2 infection (PASC), or just long COVID-19, might develop after an acute phase of the disease. They’re expressed in some symptoms that last for a long time after the initial COVID-19 infection. They can impact multiple organs, systems, and mental health even if the disease proceeded mildly or was asymptomatic.

It should be mentioned again that depression and long COVID are closely intertwined. Sharing biological mechanisms of onset they can be a trigger for each other. Depressed people are at higher risk of more severe illness and hospitalization. [9] These are among the main risk factors for long COVID. At the same time, this illness can lead to depression through different factors:

• Prevalence of depression in long COVID. Depressive symptoms persist in nearly 13% of patients 13 months post-infection. [10]
• Neurological harm. Severe COVID-19 causes reduced oxygenation, leading to limbic system shrinkage. It worsens mood regulation. [11] The disease also violates gut microbiota work, reducing serotonin/dopamine production and strengthening depression. [12]
• Hormonal problems. Chronic stress from long COVID causes cortisol imbalance, amplifying depressive symptoms. [12]
• Psychosocial and behavioral issues. The consequences of the disease lead to worse work performance, adding anxiety and depressive thoughts about the future. Possible stigmatization of people with COVID-19 also can bring up alienation and loneliness.
• Pandemic-related job loss, isolation, and grief increase depressive risk.

Mental and physical health are strongly connected. It also concerns depression and COVID risk factors. These two illnesses surprisingly have a lot in common. They even share some biomarkers. Depression isn’t considered a direct factor for COVID-19. However, it dramatically impacts the possibility of catching the virus and how severe the symptoms are. The link between them doesn’t vanish in the case of long COVID. Conversely, it becomes more complex when these illnesses combined affect devastatingly patients’ mental and physical health. So, if you experience COVID or post-infection symptoms, don’t hesitate to contact our specialists from URP Behavioral Health for timely help.

References:

1. Dani Blum. Why Does Mental Illness Raise the Risk of Severe Covid? https://www.nytimes.com/2024/10/21/well/covid-mental-health-anxiety-depression.html. Oct 29, 2024
2. Nicole Rura. Psychological, not physical factors linked to long COVID. https://news.harvard.edu/gazette/story/2022/09/depression-anxiety-may-escalate-chances-of-long-covid-says-study/. Sep 7, 2022
3. Liang Zihao, Song Jinyun, Gu Shuanglin, Chen Xiuzhen, Zhao Hongyu. The relationship between COVID-19, depressive disorder, and anxiety: a bidirectional Mendelian randomization study. https://www.frontiersin.org/journals/psychiatry/articles/10.3389/fpsyt.2023.1257553/full. Oct 19, 2023
4. Marybeth Gallagher. Can depression cause lasting changes in immune cells? https://www.medicalnewstoday.com/articles/can-depression-cause-lasting-changes-in-immune-cells. Apr 19, 2022
5. Beatriz Cañas-González, Alonso Fernández-Nistal, Juan M Ramírez, Vicente Martínez-Fernández. Influence of Stress and Depression on the Immune System in Patients Evaluated in an Anti-aging Unit. https://pmc.ncbi.nlm.nih.gov/articles/PMC7417678/. Aug 4, 2020
6. Robert Dantzer, Jason C O’Connor, Gregory G Freund, Rodney W Johnson, Keith W Kelley. From inflammation to sickness and depression: when the immune system subjugates the brain. https://pmc.ncbi.nlm.nih.gov/articles/PMC2919277/. Jan 9, 2008
7. Bokszczanin A , Palace M, Brown W, Gladysh O, Tripathi R, Shree D. Depression, Perceived Risk of COVID-19, Loneliness, and Perceived Social Support from Friends Among University Students in Poland, UK, and India. https://www.dovepress.com/depression-perceived-risk-of-covid-19-loneliness-and-perceived-social–peer-reviewed-fulltext-article-PRBM. Jun 29, 2022
8. Jamie Rutland-Lawes Anna-Stiina Wallinheimo, Simon L Evans. Risk factors for depression during the COVID-19 pandemic: a longitudinal study in middle-aged and older adults. https://pmc.ncbi.nlm.nih.gov/articles/PMC8438514/. Sep 2, 2021
9. Alexandra Benisek. Long COVID and Depression. https://www.webmd.com/covid/long-covid-and-depression. Oct 10, 2024
10. Padmashri A Shetty, Lena Ayari, Jessica Madry, Colton Betts, Diana M Robinson, Batool F Kirmani. The Relationship Between COVID-19 and the Development of Depression: Implications on Mental Health. https://pmc.ncbi.nlm.nih.gov/articles/PMC10441207/. Aug 21, 2023
11. Sara Novak. People With Long COVID Face Alarming Rates of Depression, Anxiety: Expert Q&A. https://www.medscape.com/viewarticle/997209?form=fpf. October 10, 2023
12. Ada’s Medical Knowledge Team. COVID-19 and depression. https://ada.com/covid/covid-19-and-depression/. Jan 29, 2025