MONTREAL -- People who have been diagnosed with COVID-19 are twice as likely to develop symptoms of major depression and four times more likely to have suicidal thoughts than the general population, according to research from a Quebec university.

The survey was conducted by a research team out of the University of Sherbrooke and will be be published soon.

“We are going a bit in reverse of what is normally done in research, but for me the most important thing is that the population is informed, as well as decision-makers,” said principal researcher and former director of public health for the Estrie region Melissa Genereux.

Genereux is currently writing an article based on the study and has already had discussions with the National Institute of Excellence in Health and Social Services to present the findings to Quebec authorities.

She said she wants to make the population aware of the threat represented by “long COVID,” or the lasting effects that persist long after the virus' acute phase has passed.

“If you are not afraid of acute COVID, I understand, especially if you're young and in good health,” she said, adding that 38 per cent of Quebecers who have had COVID reported symptoms of major depression.

The rate of those symptoms in the general population is 17 per cent.

Genereux hypothesized that, factoring in psycho-social and economic factors, the virus could lead to adverse consequences in the nervous system or brain.

Long-term symptoms of COVID-19 have already been found to include headaches, shortness of breath, fatigue, loss of smell and difficulty concentrating. However, it's not known whether the persistence of those symptoms has had an impact on depression of suicidal ideation.

Genereux's team monitored the impacts of the pandemic and its collateral effects since it began last March. The team carried out surveys in September and November 2020 and February 2021.

The three groups of respondents were divided into those diagnosed with COVID-19, those who had been in close contact with the virus or believed themselves to have symptoms and those with no close connection to the disease.

They were able to isolate a sample of 600 adult respondents who had been diagnosed with COVID-19. Genereux said she initially expected the symptoms of depression to be mainly related to stress, isolation or stigma, but was surprised by the results.

“If there are more symptoms in people who have been diagnosed than in those who have seen the disease up close, with the stress of isolation, it pushes us towards the hypothesis that it's the infection that causes biological disturbances,” she said.