Psychological distress has been linked to an increased risk of long Covid.

To determine the effects of psychological distress before Covid-19 infection on the development of long Covid, researchers from the Harvard T.H. Chan School of Public Health recruited more than 54,000 people for a study in April 2020.

To begin, they asked participants about their levels of depression, anxiety, worry, perceived stress, and loneliness. Over the next year, more than 3,000 participants contracted the virus, and following further questioning, the team discovered that such conditions were "more strongly" associated with developing long Covid than physical health risk factors such as obesity, high blood pressure, and asthma.

"After analysing the responses and comparing those who developed long COVID to those who did not, the researchers determined that distress before COVID-19 infection, including depression, anxiety, worry, perceived stress, and loneliness, was associated with a 32 per cent to 46 per cent increased risk of long COVID," the report stated. "These types of psychological distress were also associated with 15 per cent to 51 per cent greater risk of daily life impairment due to long COVID."

Symptoms of long Covid include fatigue and brain fog for longer than four weeks after infection.

"To the best of our knowledge, this is the first prospective study to show that a wide range of social and psychological factors are risk factors for long COVID and daily life impairment due to long COVID," added senior research scientist Andrea Roberts. "We need to consider psychological health in addition to physical health as risk factors of long COVID-19. These results also reinforce the need to increase public awareness of the importance of mental health and to get mental health care for people who need it, including increasing the supply of mental health clinicians and improving access to care."

Full study results have been published in JAMA Psychiatry.