The study, published today in the Journal of Neurology, Neurosurgery and Psychiatry and led by researchers from King’s College London, analysed data from 421,977 participants of the ZOE COVID Symptom app. Of that group 26,998 had tested positive for SARS-CoV-2 between February 23rd and April 12th 2021. Previous studies have reported that COVID-19 survivors were at an increased risk of mood and anxiety disorders after infection. The authors of this study sought to compare prevalence of anxiety and depression in individuals with or without COVID-19 infection and assess the influence of other common risk factors.

Researchers found that anxiety and depression were slightly more prevalent in people who tested positive for COVID-19 (30.4%) versus those who tested negative (26.1%). When adjusting for factors such as age and sex, researchers found this modest increase in reporting in those testing positive for COVID-19 was statistically significant.

No association was found between a positive SARS-CoV-2 test and anxiety or depression symptoms in participants younger than 40 years. Analysis showed that more recently infected groups were more likely to experience mental health problems compared to participants who had been infected more than four months before. The authors believe this is likely to mean the adverse effect on mental health lessens over time.

The analysis also examined how factors such as pre-existing physical and mental conditions, obesity, and age were associated with anxiety and depression symptoms. Regardless of how they tested for COVID-19, people who had an obese BMI were 61% times more likely to experience anxiety and depression symptoms compared to people with a healthy weight, while individuals with other health conditions or learning disabilities saw 25%-35% increase of odds.

The people most at risk of experiencing anxiety and depression symptoms in the months analysed were those who reported a previous mental health condition, which included depression, anxiety disorder and bipolar disorder. They were at 126% increased risk of experiencing these symptoms.

Dr Claire Steves, Reader from King’s College London and lead researcher said: “This research puts the relationship between COVID-19 infection and mental health in context. We found a slightly elevated risk of feeling anxious or down for people who had previously had COVID-19, but this was small compared to major risk factors for mental health problems such as obesity, and previous health problems or disabilities.”