Some COVID-19 patients may experience psychological disorders from the virus, according to a peer-reviewed article published by UC San Diego psychiatrists this week.
The paper, which appears in the Brain, Behavior, and Immunity journal, compiles evidence from past epidemics, like the deadly and widespread 1918 flu, as well as more recent events.
Below is a transcript of the extended interview. It has been edited for length and clarity.
SHALINA CHATLANI: Susie, do you mind kind of giving me an overview of the connection between the brain and the body's immune system?
SUZI HONG: The evidence and literature now show that the brain constantly communicates with the immune system and the immune system communicates back to the brain. And in the cases of virus infections, such as COVID-19, what we think is that either the virus itself or virus-infected cells may [travel] to the brain.
The brain is supposed to be closely guarded by a barrier called the blood-brain barrier. So, in the case of these types of illnesses or an acute illness or chronic conditions, those barriers can be compromised.
EMILY TROYER: Once immune cells or cytokines have entered into the central nervous system, they basically cause inflammation. And, inflammation in any part of the brain that can lead to different symptoms depending on the part of the brain that's affected.
So patients who have acute inflammation … they present a lot of highly, highly variable presentations. So you can see changes in sleep, changes in alertness, changes in mood. Some people might have depressed mood. Some people might have euphoric mood. You can experience hallucinations where you start to see or hear things that weren't there before or that other people don't see or hear. You can have difficulty thinking. You can have difficulty with sensation, like the lack of taste and smell, which has been described with COVID-19. You can have difficulty moving parts of your body.
Right now, what seems to be described, particularly in some studies coming out of Wuhan, is that people who are severely infected and hospitalized have what we call an encephalopathy, which basically just means change in mental status.
CHATLANI: You've mentioned a number of symptoms that are related to viral infections that we've seen in the past and sort of anecdotally from emerging evidence and stories out of Wuhan, China. But this article itself is a review of literature around viral infections and how they might have psychological impacts. Why do you think we can take evidence from past diseases, even if they're respiratory in nature and conclude similar psychiatric responses with COVID-19?
HONG: That’s a very good question. Generally, there is an actively expanding and fairly large literature on immune system dysregulation and the effect on the brain and also a lot of the brain related outcomes and functions and mood.
TROYER: We do have to have appropriate caution with extrapolating from past pandemics, particularly because the largest pandemic that we've experienced in the most recent history would have been around the early 20th century with the flu pandemic of 1918, which, of course, is an influenza virus and not a coronavirus.
So we do have to be careful about extrapolating data from that. But if you go back in history a little bit, you see neuropsychiatrist like Karl Menninger and Constantin von Economo around the early 20th century, really noting that around the time of the influenza pandemic, they're also describing what they call epidemics of psychosis or epidemics of encephalitis, which basically means inflammation of the brain. And so for a period of about 10 years in the early 20th century, what they saw is individuals with a host of neurologic and psychiatric symptoms at the same time sometimes following an infection.
Now, because that's over 100 years ago, we can't say for sure if that was related to influenza or if it was related to the inflammation that that infection could have caused. But I think what it does is it gives us reason to pause and say this is something that we should be looking for.
CHATLANI: It does seem like this is sort of an unprecedented moment in our lives in a lot of people are experiencing a range of emotions right now. And so, as you had mentioned, do you think there's gonna be a larger public health issue or there needs to be a response to psychiatric conditions?
TROYER: Yes, I think that we are going to need a lot of services for the general public, for frontline health-care workers. One of the messages of the article that we wrote is that going forward, it might be difficult to ascertain if someone is experiencing emotional distress or changes in behavior. Is that a result of the psychological distress of having experienced a pandemic or is that related to the effects of the virus or inflammation in someone who is infected?
HONG: As Ema mentioned there are published data… about PTSD, sleep disorders, anxiety with SARs. And because of the general stress, the general public may experience chronic stress… and in times of crisis chronic stress may result in longitudinal outcomes in psychiatric conditions like anxiety and depression. The purpose of this article is to really raise awareness and to draw the medical attention, medical community's attention in the matter. And in order to do that we need to [highlight the data] and be careful when extrapolating data from previous cases.
CHATLANI: Not everyone who experiences coronavirus will also experience a psychological condition, right?
TROYER: Right. And I would say not everyone will experience a neurologic condition, psychiatric condition, psychological distress … We don't want to add to anxiety or add to panic for the public. But we do hope to shine light on this for the medical community and also for the public to know that if you're experiencing changes in mood, thinking behavior, these are things that we want you to talk about and we want you to share with your doctors because we're going be learning about this together.
