A third of COVID-19 survivors have been diagnosed with a neurological or psychiatric condition in the six months after being infected, according to the first large-scale research comparing the risks to other illnesses including influenza.

The University of Oxford study analyzed health records of 236,379 COVID-19 patients infected last year, according to a report in The Lancet Psychiatry journal.

As might be expected, anxiety and mood disorders were the most common diagnoses, at 17% and 14% of patients respectively. But the study also found 7% of those made sickest by the virus had a stroke and 2% were diagnosed with dementia.