The European office of the World Health Organisation (WHO) warned on Friday that it expects to see an increase of people struggling with "severe mental health challenges" over the next few months as the toll from the COVID-19 pandemic is exacerbated by the winter season.
It also urged everyone to "remain at home" even if official guidelines in their countries allow for Christmas gatherings.
Dr Hans Kluge, WHO Europe's director, reiterated in a statement that the global pandemic has resulted in a growing mental health crisis on the Old Continent whose impact is likely to be "long-term and far-reaching".
He warned that the mental toll of COVID-19, which has impacted people indiscriminately, "will be compounded by anxieties that often present during the winter and holiday season."
"We expect to see a larger number of people facing more severe mental health challenges in the coming months as the reality of this experience takes hold," he added.
In a survey conducted in 25 developed countries during the first wave of the pandemic in the spring and released by the European Commission, 28 per cent of respondents reported feeling lonely and 27 per cent said they had felt depression or anxiety.
The winter months traditionally see an uptick in mental health problems with people suffering from Seasonal Affective Disorder (SAD) — a form of depression that in a normal year usually impacts about 5 per cent of adults in the US, according to the American Psychiatric Association (APA).
The disorder is linked to the biochemical imbalance in the brain prompted by shorter daylight hours and less sunlight. The organisation stressed that the symptoms can be distressing and interfere with daily functioning.
Europe is currently fighting off a second wave of the pandemic and varying levels of restrictions, including lockdowns, are in place. People are by-and-large urged to restrict travel, remain at home and see as few people as possible.
Dr Kluge urged everyone to mitigate feelings of anxiety and depression by staying active and findings ways to connect with others.
He also called for authorities to provide "specialised care and support services" for those most inflicted and to promote mental health care in communities in which "mental health challenges remain deeply stigmatised".
"In this season of giving, protecting our own mental health and well-being, and promoting that of others, is one of the best gifts we can give," he said.
On Christmas celebrations, which will be vastly different this year, Dr Kluge argued that even those permitted to meet with other households should avoid it. "The safest thing right now is to remain at home."
"My family, including my elderly parents and I, have made the difficult decision to spend the holidays apart and at home. I am holding myself accountable with a reassurance that next year we can hope to be together again," he went on.
In England, authorities are allowing up to three households to gather for Christmas, but have urged for "smaller, shorter" festivities. The nighttime curfew in France is to be lifted on Christmas Day and up to six adults will be able to celebrate together.
German authorities have also called for contacts to be kept to "a minimum" over the holiday period. Italy, however, is banning people from leaving their home town on Christmas Day.