The 10 years that Anna Rayner spent on incap­acity benefit (IB) passed in a haze. Signed off work by her doctor after a nervous breakdown, she was under no pressure to think about returning to employment, and she says she felt her self-confidence shrivelling away.

"I tended to avoid mentioning that I was on incapacity benefit to people I didn't know well," she recalls. "It is something that's very hard to admit to. It makes you feel like you're a failure. I think people see claimants as lazy. I was going nowhere, and I felt guilty about it."

Rayner, 41, was eased back into the job market two years ago, when she set up her own business as a complementary ­therapist. It was a progression made possible only with the intensive assistance of her local job centre, a community support centre and a welfare-to-work organisation.

Policymakers should take note of her experiences, because Rayner represents a new breed of modern IB claimants far removed from the stereo­typical image of middle-aged, male, ex-industrial workers. If officials are to ­succeed in their drive to reduce the numbers of people claiming these ­benefits, they will need to tailor their strategies more directly towards the needs of women such as Rayner.

A study from Sheffield Hallam University, published this week, shows that the number of women on IB has soared since the early 1980s, rising more than threefold from 350,000 to 1.1 million, so that there are now almost as many working-age women on incapacity benefits as men.

The findings of the Women on ­Incapacity Benefits report will make essential reading for those in this and future governments charged with cutting the ballooning IB bill, which the Department for Work and Pensions (DWP) places at about £6.5bn annually, but which academics estimate rises as high as £14bn when all the associated benefits, such as housing benefit, are factored in.

Employees in the benefits advice ­sector have been aware of the changing profile of this group for many years, but the trend has been little understood. The ­researchers – led by Steve Fothergill, a professor in Sheffield Hallam's centre for regional economic and social research – provide for the first time detailed analysis of the reasons behind the shift.

Female factor

Fothergill says: "It has long been accepted that in the 80s and 90s, job losses from industries such as coal, steel and ­engineering pushed many men on to ­incapacity benefits. This was characterised as a male problem. The high numbers of women claiming incapacity benefits in the same places had been a puzzle because job opportunities for women have mostly been increasing."

Like men, the majority of women who claim IB (60%) tend not to have any ­qualifications and their previous work experience is primarily in low-grade ­manual jobs; some 40% have been out of work for more than 10 years.

The researchers found no evidence that women across the country were becoming sicker as a whole, and therefore more in need of IB. The increase was in part the consequence of growing numbers of women in the workforce as a whole, and in part a manifestation of "hidden ­unemployment", they concluded. Where jobs are relatively readily available – in the south-east, for example – the number of claimants is lower. Where there are few jobs to be found, more people are directed towards this benefit. The researchers ­estimate that 430,000 of those women on IB could be expected to be in employment in a genuinely fully employed economy.

The rise is also attributed to a new ­blurring of the lines between typically male and female employment sectors. "Miners and steelworkers who were made redundant in the 80s and 90s were often reluctant to take what they considered to be 'women's jobs'," Fothergill says. However, their sons have not had the same choice, and more men are now ­competing for the same jobs as women. "One of the long-term consequences of job losses among men has been to push more women out of the labour market and on to benefits," Fothergill says. "Unemployed women with poor skills and poor health have ended up on incapacity benefits."

Only a quarter of these women say they would be unable to do any sort of work, the report found, but just one in 20 are actively looking for work.

Historically, Fothergill argues, IB has been an attractive concept from almost everyone's perspective. It suited the government, because it acted as a convenient way of hiding unemployment, and suited employers "because it has absolved them of the responsibility of hiring people who are less than totally in the best health".

It has also suited claimants, Fothergill adds, because it is not means-tested, and so recipients who have working partners have been better off than they would be under jobseeker's allowance.

The sickness benefits system is currently undergoing radical reform, as claimants are gradually shifted on to the new employment and support allowance (ESA), which was launched in 2008. A DWP spokeswoman, says it introduced ESA "to ensure that no one – man or woman – gets left behind to a life on benefits". IB claimants are still not required to go through as many hoops to receive their money as people claiming income support.

The study recommends a two-pronged response from the government: ­"sustained and intensive" support to help these women back to work, as well as physical and often mental rehabilitation. "These numbers will not be brought down just by hauling people in for work-focused interviews," Fothergill argues.

The report also points out that since claimants are concentrated in areas of high unemployment, there is an urgent need for economic regeneration. "Unless there are jobs for these people to go to, we are not going to see a decrease in the numbers of people on incapacity benefit," Fothergill says.

Given the harsh economic climate, the report questions the wisdom of extending compulsory back-to-work ­preparation schemes, in the light of the "often ­formidable obstacles to re-employment".

Abi Levitt, marketing director of Tomorrow's People, a charity that works with long-term unemployed people to get them back to work, says staff are seeing equal numbers of men and women on sickness benefit joining their motivation and confidence-building sessions. "We don't take a different approach for women, she says. "The key issue for both women and men is loss of confidence."

Rayner believes that she would never have had the courage to move off these benefits and into work without the support of a disability adviser at her local job centre, Milun Women's Centre in Leeds, and assistance from welfare-to-work organisation A4e. "It's quite a scary step to take, particularly when you don't feel very confident, and there is a temptation to stay safe by doing nothing and remaining on benefits," she says.

The decision to set up her Ray of Light holistic therapies company has improved her finances only modestly, but the step has given her a new sense of fulfilment. She says: "I feel that I have a sense of purpose in my life."