Roughly two-thirds of Americans with a diagnosed mental health condition were unable to access treatment in 2021, though they had health insurance. And only a third of insured people who visited an emergency department or hospital during a mental health crisis, received follow-up care within a month of being discharged.

These are among the findings of a new report by the actuary firm Milliman, released Wednesday. The mental health advocacy group, Inseparable, commissioned the report and also released an accompanying brief offering policy solutions to address the gaps in mental health care.

“We kept hearing nightmare stories about Americans not getting the treatment that they needed because insurance companies were denying them care,” says Bill Smith, founder of Inseparable. “But we didn’t have enough data to show just how extensive and deep the problem was.”