(Bloomberg) -- Britain is in the grip of a mental health epidemic that has left almost 1 million people on disability support and is costing the government billions of pounds, analysis of official figures by the Institute for Fiscal Studies has found.

Four-fifths of the increase in the number of disability benefit claims over the past two decades can be accounted for by those with psychiatric conditions such as mental health and learning difficulties, the research group said.

Those numbers have increased despite a shake-up of the system in 2012 that was meant to reduce spending on disability benefits by 20%. Instead, people claiming support rose from 2% to 6% of the adult population between the early 1990s and 2020-21. The cost of the benefit has almost doubled compared with forecasts.

The data “reflects an increasing rate of mental health conditions across society as a whole,” said Heidi Karjalainen, a research economist at IFS and an author of the paper. “If this trend continues -- or is even hastened by the pandemic -- it will add further pressure to disability benefit spending.”

A total of 2.2 million working age people in the UK are now on disability benefit, with 944,000 citing mental health as their main condition. Spending just prior to the pandemic was about £11 billion per year. Before the 2012 reforms, it was forecast to be around £6.5 billion at this point, the IFS said.

The figures also highlight a labor shortage, with 200,000 people dropping out of work since the pandemic due to long-term sickness. The majority of those have declared mental health issues.

The research, funded by the Joseph Rowntree Foundation, pointed to a link between disability and deprivation. Disabled people now make up almost half of the most deprived working-age adults in the country, and about 1.1 million do not receive benefits.

The IFS said the system was buckling under the strain of the demands it is under. It pointed to the long waiting time between applying for benefits and receiving them, five months on average.

Of the million disabled and deprived people who do not get disability benefits, 59% are not in paid work, 58% are women, 77% do not have a degree, 58% are single, and 60% have mental health, social or behavioral problems. 

All the proportions are higher than the overall working age population, the IFS said.

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