People hospitalized with severe coronavirus infections are likely to experience delirium, confusion or post-traumatic stress disorder (PTSD), research in a leading medical journal suggests. 

The report, published in the Lancet, looked at different coronavirus strains including severe acute respiratory syndrome (SARS) that started in 2002, Middle-East respiratory syndrome (MERS) from 2012, and early data from the ongoing COVID-19 pandemic.

The psychological symptoms are exacerbated by long stays in intensive care units (ICU) and the intrusive experience of being put on a ventilator, researchers wrote. 

The report examined COVID-19 cases from Italy and the UK, the two European countries with the highest death tolls, as well a smaller number of subjects from China, where cases were first reported.

Researchers found evidence of negative psychological effects – confusion and delirium – in more than 60 percent of COVID-19 cases that required ICU treatment. The report recommended that doctors remain vigilant to further psychological effects in recovering patients, as 33 percent of survivors from the SARS and MERS epidemics experienced PTSD two years after they were seriously ill. 

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The report notes how political and economic conditions can contribute to the psychiatric effects, citing the "wider social impact of the pandemic and the governmental response, including physical distancing measures and quarantine. 

"Both the infected and non-infected population might be susceptible as a result of certain experiences, such as widespread anxiety, social isolation, stress in healthcare workers and other essential workers and unemployment and financial difficulties."

Co-leader of the research, Jonathan Rogers of University College London's psychiatry department, said: "Most people with COVID-19 will not develop any mental health problems, even among those with severe cases requiring hospitalization, but given the huge numbers of people getting sick, the global impact on mental health could be considerable.

"Our analysis focuses on potential mental health risks of being hospitalized with a coronavirus infection and how psychiatric conditions could worsen the prognosis or hold people back from returning to their normal lives after recovering."

The report examined 72 studies from across the world that were carried out after the 2002 SARS outbreak and 10 years later, following MERS. In total, the review looked at 3,500 patients who were hospitalized with the respective viruses. 

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The results revealed that almost a third of patients hospitalized with MERS and SARS developed PTSD. In the subjects, rates of depression and anxiety were high, with around 15 percent of patients suffering a year after overcoming the virus. A further 15 percent experienced the symptoms of anxiety or depression without being diagnosed and yet another 15 percent suffered from other psychological effects including insomnia and mood swings. 

While research into COVID-19 is ongoing and partial, early evidence suggests that similar levels of delirium and confusion could be present, according to the researchers.

The report stresses, however, that its findings are based on those with serious cases of the virus. Early data suggest the majority who contract COVID-19 only experience mild symptoms and do not require ICU treatment.

Check out The Pandemic Playbook, CGTN Europe's major investigation into the lessons learned from COVID-19