Spending more than a week in bed with Covid may be linked to an increase in the risk of long term damage to mental health, new research suggests.

The study found that people with coronavirus who were not admitted to hospital were more likely to experience symptoms of depression up to 16 months after diagnosis, compared to those never infected.

Those who were bedridden for seven days or more had higher rates of depression and anxiety, compared to people who were diagnosed with the virus but never bedridden.

Although most symptoms eased within two months after diagnosis, patients who spent a week or more in bed were more likely to experience depression and anxiety over the 16-month study period.

Patients with severe Covid often experience inflammation which has previously been linked to chronic mental health effects, particularly depression.

Researchers suggest why patients who spent longer in bed had depression or anxiety rates could be due to a combination of worrying about long-term health effects as well as Covid symptoms persisting.

Study author Professor Unnur Anna Valdimarsdottir, of the University of Iceland, said: “Our research is among the first to explore mental health symptoms after a serious Covid-19 illness in the general population up to 16 months after diagnosis.

“It suggests that mental health effects aren’t equal for all Covid-19 patients and that time spent bedridden is a key factor in determining the severity of the impacts on mental health.

“As we enter the third year of the pandemic, increased clinical vigilance of adverse mental health among the proportion of patients with a severe acute disease of Covid-19 and follow-up studies beyond the first year after infections are critical to ensure timely access to care.”

Until now most studies have looked only at adverse mental health impacts for up to six months after a Covid diagnosis.

Much less is known about the long-term mental health impacts beyond that, particularly for patients not admitted to hospital with varying degrees of Covid severity.

In the study researchers looked at the prevalence of depression, anxiety, Covid-19 related distress and poor sleep quality among people with and without a diagnosis of the disease from 0–16 months.

They drew upon data from seven groups of people across Denmark, Estonia, Iceland, Norway, Sweden and the UK.

Of the 247,249 people included, 9,979 (4%) were diagnosed with the virus between February 2020 and August 2021.

Overall, people diagnosed with Covid-19 had a higher prevalence of depression and poorer sleep quality compared to individuals who were never diagnosed – 20.2% versus 11.3% experienced symptoms of depression, and 29.4% versus 23.8% experienced poor sleep quality.

People diagnosed with coronavirus but never bedridden due to their illness were less likely to experience symptoms of depression and anxiety than those not diagnosed with it.

The researchers suggest one explanation for this is that the return to normal lives is a relief for these individuals while those still not infected are still anxious about getting infected.

However, over 16 months, patients who were bedridden for seven days or more were 50-60% more likely to experience higher depression and anxiety compared to people never infected during the study period, the researchers found.

Co-author Ingibjorg Magnusdottir, of the University of Iceland, said: “The higher occurrence of depression and anxiety among patients with Covid-19 who spent seven days or longer bedridden could be due to a combination of worrying about long-term health effects as well as the persistence of physical long Covid symptoms well beyond the illness that limit social contact and may result in a sense of helplessness.

“Equally, inflammatory responses among patients with a severe diagnosis may contribute to more persistent mental health symptoms.

“In contrast, the fact that individuals with a mild Covid-19 infection can return to normal lives sooner and only experience a benign infection likely contributes to the lower risk of negative mental health effects we observed.”

The findings are published in The Lancet Public Health journal.