Almost a quarter of Scottish adults have felt lonely since lockdown restrictions began, a new survey indicates.

Research carried out by YouGov for the Mental Health Foundation Scotland found almost a quarter (24%) of Scottish adults surveyed reported feeling lonely after restrictions were introduced.

This is up from 11% who said they felt lonely in a survey carried out shortly before the lockdown came into force on March 23.

For the latest survey, part of a major UK-wide longitudinal research project entitled Coronavirus: Mental Health and the Pandemic, 1,028 adults in Scotland were questioned on April 2 and 3 on whether they felt lonely in the previous two weeks.

Those most affected were people aged 18-24, as 43% told researchers they felt lonely, up from 26% in the pre-lockdown survey that questioned 1,015 Scottish adults and took place on March 17 and 18.

The next most affected group was those aged 35-44, with almost a third (32%) reporting feelings of loneliness.

One in six people aged over 55 said they had felt lonely in the previous two weeks.

Lee Knifton, Mental Health Foundation Scotland director, said: "Our data reveals that hundreds of thousands of people across Scotland are experiencing feelings of loneliness - which is a key risk factor for developing or worsening mental health problems."

"The concern is that the longer the pandemic goes on for, the more feelings become long-term.

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"The impact of long-term loneliness on mental health can be very hard to manage.

"That's why we're urging people to reach out to friends and family of all ages, particularly older and more vulnerable people at risk of isolation - and think about what steps we can take to help them stay connected."

He added: "While the initial priority must be to prevent loss of life, we fear that we may be living with the mental health impacts of the coronavirus situation for many years to come.

"This is especially true of vulnerable groups and it is critical that governments and others are mindful of this in developing policy as we go forward."

The charity welcomed the launch of the Scottish Government's Clear your Head campaign on Tuesday to assist people in protecting their mental health during the pandemic.

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The foundation wants the Scottish Government to take specific action to protect the mental health of young people as well as older adults through public health campaigns and investment in local peer support.

The UK-wide project study is being led by the Mental Health Foundation in partnership with Strathclyde, Cambridge and Swansea universities and Queen's University Belfast.

A Scottish Government spokesperson said: "The restrictions on our lives, whilst vital, are undoubtedly tough. It is an understandable cause of anxiety for many people and we appreciate everyone's efforts to prevent the spread of the virus.