The authors of the study also suggested that people who had lost their job found claiming Invalidity Benefit preferable to claiming Unemployment Benefit because it paid more and did not carry the same stigma as being unemployed. A paper published in the Economic Journal suggested that changes to the benefits system encouraged claimants to go onto Invalidity Benefit rather than Unemployment Benefit. It argues that changes to the criteria for receiving Unemployment Benefit made it harder to receive. The paper also says that people who were near retirement age were possibly incentivised to stay on Invalidity Benefit because they could claim the benefit for five years after their retirement, and unlike the state pension, it was not taxed. There have been claims that the government was using Invalidity Benefit to lower the unemployment statistics. A report by Sheffield Hallam University showed that Invalidity Benefit claims started to rise when unemployment rose in the late 1970s and early 1980s, and argued that this indicated that many claimants were not too unwell or disabled to work, as the number of people with serious illnesses and disabilities would be expected to be constant. An earlier paper by two of the same authors made a similar argument, and showed that people living in areas where there had been a high number of job losses (such as traditional industrial areas) had the biggest growth in people claiming Invalidity Benefit. As well as this, a paper published in the Journal of Public Health Medicine argued that people with mild mental disorders were increasingly likely to claim Invalidity Benefit, and showed that the rate of people claiming Invalidity Benefit where their main disability was Depression or Anxiety had grown rapidly between 1985 and 1995, but that there was a much smaller increase in claims over the same period for potentially more disabling mental disorders, such as psychosis. The author claimed that this supported the view that the government was using Invalidity Benefit to conceal unemployment levels. An editorial in the British Journal of General Practice published in 1990 argued that GPs felt pressured into giving patients sick notes because they did not have time to fully assess the patient's fitness to work, which was contributing to the rise in Invalidity Benefit claims.