Changes to the welfare system are having a "devastating" impact on disabled people, Citizens Advice Scotland has said.

In a report examining a number of cases from across Scotland, the advice organisation says that UK Government reforms have led some people to contemplate suicide after being taken off sickness benefits.

And it claims that the new Employment and Support Allowance (ESA) is "unfit for purpose" and "failing to live up to its billing".

Head of policy Susan McPhee said the UK Government has redefined what it means to be ill.

Noting that the number of people seeking help from the CAB increased by one-third in 2011, she said: "The picture remains as bleak as ever.

"The intention of ESA was a good one. It was meant to help those on sickness benefits: to identify those who were capable of work and help them into employment, while continuing to support the rest and saving taxpayers money in the process. That was the plan.

"In reality, ESA is failing to live up to its billing."

The service said more than 170,000 long-term sickness benefit claimants will be reassessed for ESA by 2014 and that an estimated 115,000 will lose their money.

About 36,000 people in Scotland will be moved to Jobseeker's Allowance, with a drop in income of £27 a week, while 65,000 will leave the benefits system altogether.

Case studies in the From Pillar to Post report included someone who told the advice service she had considered suicide because of the changes.

Advisers reported a number of calls from people who said their health is deteriorating because of stress.

Another case study describes someone who was found fit for work despite depending on family for help with cooking, showering and to accompany him outside because of his poor balance and vision.

The report was published on the day a Holyrood committee was due to meet for the first time to look into the impact to Scotland of the UK Government's Welfare Reform Bill.