Carers have described suffering an “avalanche of utter stress” due to the government’s “abhorrent” approach to clawing back benefits, as official figures revealed the widespread ill health of those caring for loved ones.

The Department for Work and Pensions has been under fire since the Guardian revealed that tens of thousands of unpaid carers are being forced to pay back huge sums – and in some cases prosecuted for fraud – over “honest mistakes” that it could have spotted years earlier.

Dozens of people who provide care for frail, sick or elderly relatives have described the “devastating” effect of the DWP’s approach, with some saying it had led them to consider killing themselves.

One woman said her mother had become “severely depressed, suicidal and self-harming” after being ordered to repay two years’ worth of carer’s allowance for mistakenly breaching the earnings allowance, currently £151-a-week, while caring for her father when he suffered a major stroke.

Another carer, forced to repay £2,100 in carer’s allowance, said she was “made to feel like a fraudster”. She added: “I couldn’t eat or sleep. I lost weight. I was on antidepressants. I was terrified I’d go to prison. I’m still traumatised, years later. It’s a terrible system. It feels like a trap.”

A third carer, whose two sons aged four and nine have chronic Crohn’s disease, said she had been left “traumatised” by the DWP’s demands to repay about £5,000.

“I cannot begin to describe the avalanche of utter stress that those DWP overpayment letters triggered,” she said. “Carers allowance and universal credit overpayments are damaging, draining and destroying the fragile lives of ill and disabled patients and their carers.”

Dr Siobhan O’Dwyer, an associate professor in adult social care at the University of Birmingham, described the government’s approach as “abhorrent” and said it was increasing the risk of unpaid carers considering or attempting to kill themselves.

She said: “This pursuit by the DWP is going to make carers feel more trapped and less supported, which is only going to increase the risk of carers thinking about or attempting to take their own lives.”

O’Dwyer, who has studied suicide and murder among unpaid carers for 15 years, said one in three unpaid carers have thought about killing themselves due to the emotional and financial strain.

This enormous stress was also leading some to kill their loved ones, she said, adding that there was about 13 murders or murder-suicides by unpaid carers each year in the UK. She added: “I think we may see more of those deaths as well in the wake of this action by the DWP.”

It is not known how many carers have already died by suicide because caring status is not part of the data collected after such a death.

Unpaid carers are allowed to earn just £151 a week on top of the minimum 35 hours of care they provide – equivalent to just 13 hours at the minimum wage – and can be fined if they breach the limit, even inadvertently, resulting in demands to pay back “overpayments” as high as £20,000.

Figures released by the Office for National Statistics (ONS) showed that nearly half of England’s five million unpaid carers reported a negative effect on their health due to the strain of looking after a loved one.

One in five unpaid carers reported low mental wellbeing, compared with 14.8% of the wider population.

About one in four reported being in “not good health”, compared with fewer than one in five adults who were not providing any unpaid care, according to the ONS.

The DWP has been approached for comment. A spokesperson previously said carer’s allowance had increased by about £1,500 for an unpaid carer since 2010. This works out as a rise of about £28 a week, or slightly higher than the rate of inflation.

They added: “We are committed to fairness in the welfare system, with safeguards in place for managing repayments, while protecting the public purse.

“Claimants have a responsibility to consistently inform DWP of any changes in their circumstances that could impact their award, and it is right that we recover taxpayers’ money when this has not occurred.”