Despite fears that a 2008 law requiring employers to cover mental health care and addiction treatment as broadly as medical health care would backfire and cause employers to drop coverage altogether, a new report from the Government Accountability Office (GAO) suggests that “mental health parity” legislation has benefited American employees on the whole, cutting costs for those who need treatment and reducing limits on care.
The Paul Wellstone and Pete Domenici Mental Health Parity and Addiction Equity Act — which was passed incongruously as part of the bank bailout legislation — sought to address the fact that many employers’ health insurance plans historically restricted benefits for mental health and substance use disorders in ways that they did not limit physical health benefits.
Opponents of the law argued that it would raise costs and ultimately cause employers to drop coverage entirely. The law doesn’t require them to cover mental health problems, only to cover them equally with physical health if they do provide coverage.
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But the new GAO report found that 96% of businesses with more than 50 employees that responded to the survey offered mental health and substance use disorders coverage both before and after the law went into effect. Only 2% said they dropped this coverage to cut costs after 2008.
The most common change after the law was passed was broader coverage, with fewer limits on things like the number of therapy visits permitted, and lower out-of-pocket costs for employees.
Unfortunately, only 24% of employers responded to the GAO survey, so it is possible that it is not representative or biased toward those that made positive changes. Only 168 employers provided usable responses. However, other national reports on mental health coverage before and after the 2008 law reported similar results.
The GAO report could not determine the quality of care received by employees or whether the changes in coverage actually improved health. The GAO reviewed the research on whether parity improves access to care, but found mixed results: 17 studies suggested either a positive effect of parity or a negative effect of limits on care, while 13 found that the law made little or no difference.
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Maia Szalavitz is a health writer for TIME.com. Find her on Twitter at @maiasz. You can also continue the discussion on TIME Healthland‘s Facebook page and on Twitter at @TIMEHealthland.