Many COVID-19 patients are likely to be at greater risk of developing mental illness say psychiatrists, after a large study found 20% of those infected are diagnosed with a psychiatric disorder within 90 days.

Anxiety, depression and insomnia are most common among recovered COVID-19 patients. The researchers also found significantly higher risks of dementia.

The study, published in the Lancet Psychiatry, analysed health records of 69 million people in the US, including more than 62,000 cases of COVID-19.

In the three months following testing positive, one in five patients were recorded as having a first-time diagnosis of anxiety, depression or insomnia.