Here is the study https://www.thelancet.com/journals/lanpsy/article/PIIS2215-0...

The study has this line which caught my attention:

> The incidence of any psychiatric diagnosis in the 14 to 90 days after COVID-19 diagnosis was 18·1% (95% CI 17·6–18·6), including 5·8% (5·2–6·4) that were a first diagnosis.

So only 5.8% of people got a first diagnosis, and the remainder of the 18% were people who had been previously diagnosed with one of these conditions.

This seems to contradict what is written in the linked article:

> In the three months following testing positive for COVID-19, 1 in 5 survivors were recorded as having a first time diagnosis of anxiety, depression or insomnia.

So it seems like the linked article has a bit of hyperbole in it.