It’s well-established that a bout with COVID can seriously affect your mental health: The virus has been linked to both the development of new psychiatric conditions, like depression, as well as the exacerbation of any existing ones you might have. But now, for the first time, a massive new study of 18 million people in the UK looked at whether vaccination can affect how much the virus can ultimately mess with your emotions—and the results may have you rolling up your sleeves if you haven’t already.
In the study, published August 21 in the journal JAMA Psychiatry, researchers at the University of Bristol looked at the health records of three different groups of people: one before vaccines were available and then two more (vaccinated versus unvaccinated) after the shots rolled out. The researchers then compared mental illness diagnoses in people before and after they tested positive for COVID.
It turned out that people who caught SARS-CoV-2 at all, regardless of vaccination status, were more likely to experience or be diagnosed with mental health conditions—including depression, anxiety, PTSD, eating disorders, addiction, schizophrenia, bipolar disorder, self-harm, and suicide—within a month of testing positive for the virus compared to the time right before they were diagnosed.
People who were hospitalized were even more likely to experience any of these problems, but especially depression. For example, people with a milder case of COVID were 1.2 times more likely to experience depression after their infection, compared with hospitalized folks, who were about 16 times more likely. (Venexia Walker, PhD, lead author of the study, tells SELF that this association was greater in people who had mental health problems before they tested positive for COVID.)
Unvaccinated people bore the brunt of this, according to the study, and they tended to be more likely to have mental health issues and deal with them for up to a year after they got sick, according to the report. However, COVID is still serious and concerning, regardless of your vaccination status, so it’s worth keeping an eye out for signs that an infection is messing with your or a loved one’s mental well-being—and then seeking help and insight from a medical professional like a primary care doctor or therapist, if necessary.
Why does COVID take such a toll on our emotional health? It’s not one hundred percent clear yet. One theory is that COVID causes inflammation in the brain and body, which triggers the release of chemicals linked to anxiety, depression, and suicidal thinking. Getting sick and feeling worried about things like hefty medical bills, missed days of work, and long COVID could also stress a person out and cause or exacerbate mental health issues. People with mental health disorders also tend to have other conditions that may increase their risk for severe COVID, such as heart disease, asthma, or type 2 diabetes. More generally, it’s also possible that the isolation and lack of physical activity that tends to happen when dealing with an infection leads to higher levels of depression or otherwise funky moods, Philip Chan, MD, MS, an infectious disease expert at Brown University, tells SELF.