People with multiple sclerosis who claim disability benefits are finding that controversial assessments are causing their condition to deteriorate or relapse, a charity has warned.
The MS Society said nearly half (48%) of those questioned who had an assessment for Employment Support Allowance (ESA) felt it was of harm to their health.
And more than a third (36%) of those who had a face-to-face assessment for Personal Independence Payment (PIP) felt the same.
The charity said the current disability benefits assessments do not take into account the fluctuating and hidden symptoms of MS, and the impact this has on sufferers, accurately.
It has launched a new campaign "MS: Enough: Make welfare make sense", also calling for the system to take adequate account of evidence provided by experienced professionals who understand the person's condition.
Of the 1,800 respondents who completed the survey, nearly a third (32%) also said benefit changes have led them to cut down on food, more than a quarter (28%) have cut down on transport and two out of five (41%) are socialising with family and friends less.
Nearly one in 10 (9%) said they have reduced spending on attending hospital appointments while 9% have cut down on medical treatment or prescriptions as a result of benefit changes.
PIP, which replaced Disability Living Allowance (DLA), has been described as unfit for purpose after it was beset by backlogs and delays which left many disabled people waiting in excess of six months, and in some cases more than a year, for their claim to be processed.
The work capability assessment system that determines if someone will receive ESA has also been dogged by controversy, with heavy criticism of the tests used to decide whether applicants are eligible.
The charity also wants the Government to undertake a full impact assessment of any further changes they undertake to disability benefits, including the knock on effects on other areas of public spending such as health and social care.
Michelle Mitchell, chief executive of the MS Society, said living with a chronic, disabling, neurological condition such as MS can be expensive.
"Having MS is enough; it should not be made harder by a welfare system that doesn't make sense for people living with the condition," she said.
"Lack of understanding of the condition and the failure to use information from medical professionals is causing stress or contributing to relapses and deteriorating health.
"This is counter-intuitive to a system designed to support people with disabilities.
"At their best, these benefits can enable people to work for longer, live rich, independent family lives and participate fully in society.
"The Government needs to recognise the reality of living with MS and make basic, common sense changes, fast."
A spokesman for the Department of Work and Pensions said: "We understand that going through the assessment process can be difficult for people suffering from conditions such as MS and our staff work hard to make it as straightforward as possible.
"The purpose of an assessment is to identify the support that a claimant needs and they are carried out by registered and experienced health professionals.
"Our staff receive training and guidance for a range of medical conditions including fluctuating conditions such as MS."