Around 18 percent of people who have had Covid-19 are diagnosed with a psychiatric disorder such as anxiety, depression, or insomnia within three months of falling sick, including those with no history of mental health problems, a new study has found. 

Researchers from the University of Oxford, UK sifted through the medical records of over 69 million patients in the US and found that almost one in five people diagnosed with Covid-19 received a diagnosis of anxiety, depression, or insomnia within the next three months, many of which had a pre-existing mental illness. However, around a quarter of people diagnosed with mental health problems after recovering from Covid-19 had no documented history of mental illness. The findings are published in the journal The Lancet Psychiatry. 

“People have been worried that Covid-19 survivors will be at greater risk of mental health problems, and our findings in a large and detailed study show this to be likely,” Paul Harrison, lead study author and professor of psychiatry at the University Oxford, said in a statement. 

“Services need to be ready to provide care, especially since our results are likely to be underestimates of the actual number of cases,” he added. “We urgently need research to investigate the causes and identify new treatments.”

Physical health problems of any nature are often linked to a rise in mental health problems. However, the risk of being diagnosed with a mental health disorder after Covid-19 is notably higher than other diseases. For example, the research showed that there is an 18.1 percent chance of getting a psychiatric diagnosis after Covid-19 compared to a broken bone (12.7 percent), kidney stones (13.7 percent), the flu (13.3 percent), and other respiratory infections (14.1 percent).

This is purely an observational study, meaning the underlying cause of this link is not fully understood. Previous studies have suggested that the stress of the pandemic and social distancing measures have taken a toll on people's mental health, even if they hadn’t personally suffered from the disease. The reason behind this is complex, but it’s thought to be tied to wider worries over health, concerns about job security, and the breakdown of support networks.

Other research has also suggested that Covid-19 affects the central nervous system and is linked to an array of unexpected neurological symptoms. Thousands of people, for example, have reported recovering from Covid-19 but continue to suffer from memory loss, fatigue, and a lack of concentration, something referred to as “brain fog”. The findings that Covid-19 patients with no previous psychiatric diagnoses are also experiencing anxiety and depression after their recovery could suggest that the infection itself might play some role in triggering the mental health problems, much like other physical illnesses. However, this is speculation for now. 

“This well-conducted study adds to a growing body of evidence that Covid increases the risk of a range of psychiatric illnesses including post-traumatic stress disorder,” commented Dr Michael Bloomfield, head of the Translational Psychiatry Research Group and consultant psychiatrist at University College London, who was not directly involved with the study. 

“This is likely due to a combination of the psychological stressors associated with this particular pandemic and the physical effects of the illness, although further work is needed to understand this fully.”