Department has carried out 60 internal reviews following deaths, and campaigners say those cases likely to be tip of the iceberg

The Department for Work and Pensions has been urged by mental health and disability charities to publish its secret investigations into suicides that may have some link to benefit changes, following revelations that it has carried out internal reviews into 60 such cases.

A Freedom of Information request by the Disability News Service has revealed that the DWP has carried out “60 peer reviews following the death of a customer” since February 2012. A peer review is triggered when suicide or alleged suicide is “associated with a DWP activity”, according to its internal guidance.

Despite growing concern over the way benefits are administered in relation to vulnerable individuals, and amid a number of reports of related deaths, the department told the Guardian it had no plans to publish the reviews.

Disabled People Against the Cuts said that, because of the way the reviews were carried out, the DWP figure was likely to be the “tip of the iceberg”.

Tom Pollard, the policy and campaigns manager at Mind, told the Guardian the figures were a concern. He stressed that suicide was a complex problem but added: “It would be helpful for organisations to see what things could be going wrong in the benefit system that could lead to these tragic situations.”

Sue Bott, director of policy and services at Disability Rights UK, said DWP reviews should be transparent.

“There have been allegations and anecdotal evidence for a while that the benefits regime has tipped people over the edge. It should be looked into in a transparent way,” Bott said. “This is not just about the nature of the decision taken as to whether it was right or wrong. It’s also about the process and there is a lot of concern about the way benefits are administered.”

The DWP’s latest figures show that sanctions to punish disabled ESA claimants had risen by 470% in 18 months, from 1,096 in December 2012 to 5,132 in June 2014.

According to DWP figures released as the result of an FoI request, 62% of adverse ESA sanction decisions in the first three months of 2014 were made against people with mental or behavioural problems (9,851 out of 15,955).

The calls for transparency from the DWP come after a number of reports of the deaths and suicides of vulnerable individuals after adverse benefit decisions.

David Clapson, 59, a former soldier and type-1 diabetic, died in July after his benefit was cut. Clapson had no food in his stomach, £3.44 in the bank and no money on his electricity card, leaving him unable to operate his fridge where he kept insulin.

MPs are to look into his death after a petition written by Gill Thompson, his sister, gathered more than 200,000 signatures.

Thompson, told the Guardian: “All I’ve ever asked for is lessons to be learned. I can’t bring him back but we should know what is going on. There are certain people who shouldn’t be sanctioned. People with terminal cancer, waiting for heart operations, people with diabetes. Before they sanctioned my brother, they knew his disability. He was waiting to hear from a job, he had been on work placement. He was claiming the bare minimum.”

Christine Norman, a nurse whose disabled sister, Jacqueline Harris, took her own life in November 2013 after her benefits were cut, said: “It’s too late for my sister. Everything is stacked against you. If you’ve got a great education, if you have great health, you’re OK. But if you haven’t, you have to fight against the odds. The government want you to work. The ones they pick are the ones that are vulnerable and ill.”

An inquest found last month that Harris, 53, of Bristol, who was partially sighted, took her own life after months of constant pain and following a “fit for work” ruling that replaced her incapacity benefit with jobseeker’s allowance. Staff at a jobcentre Harris was told to attend had to call an ambulance after she blacked out in pain.

Disabled People Against Cuts said that, because the DWP’s reviews only relate to suicides or alleged suicides and were triggered by regional managers within the benefit system, the number of deaths was likely to be far higher than the 60 cases that reached review.

Anita Bellows, of Disabled People Against Cuts, said: “The triage for advising whether a peer review is to be carried out is done by regional managers at seven regional centres, who may not have an interest in putting them forward. Also, the guidance for peer review is focused on suicide, which does not cover people like David Clapson.”

She called on the DWP to open a proper investigation into the deaths, and include evidence from medical experts. “These should be public documents” she said. “They are also only focused on the process. There are no medical experts on it.”

The DWP said it was unable to disclose the names of individuals under review because of provisions of the Social Security Administration Act.

However, the Mental Welfare Commission of Scotland, a Scottish government-funded watchdog, published its comprehensive review of the suicide of a claimant known only as Ms DE this year. The MWCS concluded that the WCA process and the subsequent denial of ESA was at least a “major factor in her decision to take her own life”. It concluded that the work capability assessment process was flawed and needed to be more sensitive to mental health issues.

Colin McKay, chief executive of the Mental Welfare Commission of Scotland, said he was disappointed with the DWP response to the report on Ms DE, who died on 31 December 2011.

“Certainly, nothing in what they said gave us confidence that if another Ms DE was claiming benefit, the outcome would be any different,” he said. “If the number of deaths are 60, that’s a lot. You would expect any organisation experiencing deaths as the potential consequences of their actions would be seriously considering whether they needed to do anything differently.”

This year a whistleblower tasked with getting claimants out of the ESA sickness benefit told the Guardian that some of her clients were homeless, many had extreme mental health problems – including paranoid schizophrenia, bipolar disorder and autism – and some were “starving” and extremely depressed after having benefits stopped. “Almost every day one of my clients mentioned feelings of suicide to me” she said.

Mind released research on Thursday that found that people with mental illness were having their benefit cut more than those with other illnesses. It also found 83% of those with mental health problems surveyed said their self-esteem had worsened, and 76% said they felt less able to work as a result of DWP back-to-work schemes.

The DWP said: “We take these matters extremely seriously, which is why we carry out peer reviews in certain cases to establish whether anything should have been done differently. However, a peer review in itself does not automatically mean the department was at fault.

“Since its introduction in 2008 there have been four independent reviews of the work capability assessment and we have made significant improvements to make it better, fairer and more accurate.”