The latest research, carried out from April 23 to May 1, also found that one in six unemployed adults surveyed said they’d had suicidal thoughts and feelings during the previous two weeks.
And nearly a third of adults surveyed said they were worried about their finances, such as bill payments and debts.
Some 2056 Scottish adults, aged 18 and over, were polled as part of a major UK-wide research project called Coronavirus: Mental Health in the Pandemic.
Lee Knifton, director of Mental Health Foundation Scotland, said: “Our research is starting to reveal how the financial and employment inequalities caused and exacerbated by the pandemic are affecting people’s mental health.
“We have very concerning evidence that hundreds of thousands of people in Scotland are worrying about fundamental financial matters and their job security – both of which are closely linked to poor mental health.
“However, it is also important to recognise that within the overall picture, it is people who were already unemployed at the start of the pandemic who are being most seriously affected. It is disturbing that more than one in six unemployed people surveyed said they’d had suicidal thoughts and feelings.
“Without further, rapid government action to improve people’s economic security, we can expect things to get worse, especially for the poorest.
“The financial inequalities that lead to increased and unequal rates of mental ill-health will be intensified and the benefits of recovery and coming out of the lockdown will not be shared equally.”
The project to track how the pandemic is affecting people’s mental health is being led by the Mental Health Foundation in partnership with the University of Strathclyde, Swansea University, University of Cambridge and Queen’s University Belfast.
Professor Alec Morton, from the University of Strathclyde, said: “Tragically, much of the pain is being borne by those who were struggling to get by even before the pandemic hit.”
The Mental Health Foundation is calling for the Scottish and UK governments to provide an economic safety net for all, both during and after the pandemic.