EDMONTON -- Patients diagnosed with post-COVID-19 syndrome, or so-called COVID-19 鈥榣ong-haulers鈥, may experience symptoms such as mood disorders, fatigue and cognitive impairment that can make it difficult to return to normal life, according to a recent study.

The Mayo Clinic study, , found that fatigue was the most commonly reported symptom of patients being treated for post-COVID-19 syndrome. Of those studied, 80 per cent reported unusual fatigue, 59 per cent had respiratory complaints, and a similar percentage had neurologic complaints.

According to the study, which includes findings from the first 100 patients to participate in Mayo Clinic's COVID-19 Activity Rehabilitation program (CARP), which evaluates and treats post-COVID-19 syndrome, more than one-third of patients said it was difficult to perform basic daily tasks, and only one in three patients had resumed their usual duties at work.

鈥淢ost patients with whom we worked required physical therapy, occupational therapy or brain rehabilitation to address the perceived cognitive impairment," Greg Vanichkachorn, medical director of CARP and first author of the study, said in a press release.

"While many patients had fatigue, more than half also reported troubles with thinking, commonly known as 'brain fog.' And more than one-third of patients had trouble with basic activities of life. Many could not resume their normal work life for at least several months."

The patients involved in the study were evaluated and treated between June 1 and Dec. 31, 2020 and were evaluated an average of 93 days after they were infected with COVID-19. The average age of the participants was 45.

Most patients in the study had no pre-existing conditions prior to contracting COVID-19, and many did not experience COVID-19 symptoms that were serious enough to require hospitalization.

"Most of the patients had normal or non-diagnostic lab and imaging results, despite having debilitating symptoms. That's among the challenges of diagnosing [post-COVID-19 syndrome] in a timely way and then responding effectively,鈥 said Vanichkachorn.

So-called COVID-19 long-haulers have been speaking out about the long-term health effects of the disease since the early days of the pandemic, and a growing body of research points towards just how impactful post-COVID-19 symptoms can be on patients.

A review of nine long-term studies published in the journal Nature Medicine in March looked at the frequency of symptoms among long-haulers, the most common of which included fatigue, shortness of breath, anxiety, depression, and post-traumatic stress disorder.

Three studies from France, Britain and China showed that between 25 and 30 per cent of patients reported sleep disturbances weeks after recovering from COVID-19. And in a cohort of 402 survivors in Italy who had been hospitalized due to COVID-19, 56 per cent tested positive for at least one psychiatric condition such as PTSD, depression or anxiety.

Some COVID-19 long-haulers have reported improved symptoms after being vaccinated, but researchers are still calling for more research to be done into the long-term effects of the disease.

"As the pandemic continues, we expect to see more patients who experience symptoms long after infection, and health care providers need to prepare for this, know what to look for, and know how to best provide for their patients' needs," said Vanichkachorn.鈥