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Ways to Guard Your Mental Health During the COVID-19 Outbreak
  1. How can a virus cause depression and other psychiatric effects?

    We’ve known for a long time that there’s a link between viral infections and mental health. We think that neuropsychiatric symptoms may be caused by the body’s immune response to viruses and other pathogens, triggering the release of cytokines systemically and locally, in areas of the brain involved in depression and other psychiatric conditions, rather than the direct effects of the pathogen.

    Increased cytokines can disrupt the production of necessary chemicals (neurotransmitters) that brain cells (neurons) use to talk to each other—which results in our normal behavioral and emotional responses to our living environment.

    Moreover, some aberrant chemicals arising from inflammation can make neurons die. When neurons do not adequately communicate with each other, or are lost, cognition, emotions, and behavior can be altered.

    Could this be happening in some people with COVID-19?

    Our review(link is external and opens in a new window) suggests that COVID’s effects on the brain may be caused by small blood clots and inflammation, which also potentiate each other. The interaction between clots and inflammation in COVID resembles what we see in traumatic brain injury in football players, for example. People with traumatic brain injury may suddenly experience personality changes, sometimes becoming aggressive or suicidal.

    The mechanical shaking that causes traumatic brain injury is different from the coagulation and inflammation that occurs in COVID, but both can ultimately cause brain damage due to little strokes and inflammation.

    Based on what we know about COVID so far, systemic inflammation may unleash chemicals that trigger symptoms such as hallucinations, anxiety, depression, and suicidal thinking, depending on which part of the brain is affected.

    We don’t think that the virus is directly invading the neurons, or other cells, in the brain. Based on an extensive search by Columbia pathologists and other groups, we’ve learned that very little of the virus actually reaches the brain because of a layer of protective cells known as the blood-brain barrier.

    But there is evidence that a small amount of virus may be able to enter the brainstem and cerebellum via circumventricular organs—openings in the blood-brain barrier that allow us to sense and respond to toxins. In fact, the little amount of virus that’s been detected in the brain has been found in these regions, which happen to be located near circumventricular organs.

    What kinds of studies need to be done now?

    Currently, we are analyzing the electronic health records of deceased COVID patients who had neuropsychiatric symptoms. In my lab, we’re analyzing the brain tissue in greater detail to look for cells and molecules that may be involved in these pathogenic pathways. We’re measuring the amount of microglia, neuronal damage, and inflammatory markers that are present in the brains of these patients.