Max Tillitt was a patient in Owatonna when he and his family learned that their health plan would no longer pay for residential treatment of his drug addiction.

Within a few months, the 21-year-old Eden Prairie resident had died of a drug overdose.

Four years later, Tillitt’s mother is part of a class-action lawsuit against a subsidiary of UnitedHealth Group that’s one of the largest behavioral health benefits companies. In March, a federal judge overseeing the case issued a blistering rebuke against the Minnetonka-based insurer, writing that UnitedHealth’s guidelines for making decisions about coverage for addiction treatment were developed through a process that was “tainted” by the company’s financial interests.

Advocates say the litigation might finally help patients overcome coverage barriers that persist despite a 2008 federal law named in part for the late U.S. Sen. Paul Wellstone for parity in coverage of mental and physical health services.

“I would suspect that there are other health plans out there that might have been using criteria that were not consistent with a medical standard of care,” said Jennifer Snow of the National Alliance on Mental Illness. “I would hope that other insurers are looking at this and thinking: We’ve got to get our act together.”

In his March ruling, Chief Magistrate Judge Joseph Spero of the U.S. District Court for the Northern District of California sided with plaintiffs who alleged coverage guidelines used by the subsidiary, United Behavioral Health, did not measure up to the standard of care. The case is now in the remedy phase. United has asked the judge to decertify the class; plaintiffs want a chance to resubmit their claims and the appointment of a special master to oversee the company.

At the time of the judge’s findings, UnitedHealth issued a statement saying the next phase of the case would show that health plan members received “appropriate care.” On Thursday, the company issued a statement saying the court’s findings were limited to coverage guidelines on the level of care used in 2017 and earlier. UnitedHealth has since switched to using guidelines from the American Society of Addiction Medicine (ASAM), the company said.

“Our policies have and will continue to meet all regulations and we are committed to ensuring our members have access to the mental health and substance use treatments covered under their plans,” the company said. “This issue underscores the pressing need to establish and gain widespread adoption of clear, evidence-based treatment standards for the management of behavioral health and substance use disorders.”

Max Tillitt played football for Eden Prairie High School and suffered a concussion at practice in 11th grade. After the hit, he experienced memory problems that complicated schoolwork and was sidelined from athletic pursuits that were central to his identity. Depression and chronic pain from the head injury led to drug use, his parents say, and then addiction.

In June 2015, Max arrived at a treatment center in Owatonna that initially called for 45 days of residential care, said his father, Stephen Tillitt. Max Tillitt had insurance through his mother’s employer-sponsored health plan, which used United Behavioral Health to administer addiction treatment benefits.

There were hopeful signs, his mom said, as Max reconnected with his love of running and began making plans for the future. “The old Max was starting to come back,” she said.

Even so, he hadn’t been stabilized on medications for his depression and bipolar disorder, she said. So the Tillitts were shocked to learn in early July that the insurer was cutting off coverage after about three weeks of treatment.

The facility initiated an urgent appeal. DeeDee Tillett says a doctor said at the time that if Max was to leave, he would almost certainly relapse. But the appeal was denied.

That left the Tillitts scrambling to arrange outpatient care and find a sober-living facility where Max could live — a process that brought complications the family believes could have been avoided with a longer stay.In September 2015, Max Tillitt connected with a dealer to buy heroin. He died of an overdose in an Eden Prairie hotel room, with his infant son and fiancée nearby.

“It’s terrible. It still hurts,” said Stephen Tillitt, an attorney. “I think Max’s case has already established that he did not get appropriate care.”

He added: “United was distorting the truth and misleading us on what our son needed.” In its statement, UnitedHealth Group said it could not discuss individual patient cases.

“Max did not have terminal cancer. Max had a treatable illness,” said DeeDee Tillitt, who works as a health care consultant. “Let’s change this. Let’s save people. Let’s fix the system.”

In his March ruling, Spero wrote that the court was not making determinations as to whether individual class members were actually entitled to benefits. Doing so would require the court to consider “a multitude of individualized circumstances relating to the medical necessity for coverage and the specific terms of the member’s plan,” the judge wrote. “Rather, [plaintiffs] assert only facial challenges to the guidelines.”

Spero found that the coverage guidelines used by United Behavioral Health (UBH) were “riddled with requirements” that generally would leave patients with narrower coverage than what’s called for by generally accepted standards of care. Plus, the process used by the company to develop the guidelines was “fundamentally flawed because it is tainted by UBH’s financial interests,” the judge wrote.

The most striking example, Spero wrote, came with UBH’s decision not to adopt guidelines from ASAM — the professional group that devised the guidelines UnitedHealth says it switched to before the judge’s ruling. Spero wrote that the decision was “not based on any clinical justification” and showed how the insurer’s finance department had “veto power.”

“UBH did not ensure that the internal process it set up for adopting and revising the guidelines insulated the individuals who developed the guidelines from financial considerations,” the judge wrote. “To the contrary, UBH included administrators from its finance and affordability departments on the committees that ultimately had to approve the guidelines.”

Spero added: “The emphasis on cost-cutting that was embedded in UBH’s guideline development process actually tainted the process, causing UBH to make decisions about guidelines based as much or more on its own bottom line as on the interests of the plan members, to whom it owes a fiduciary duty.”

In March, the American Medical Association called the judge’s ruling “a detailed takedown of UBH’s practices.” The group called on policymakers to determine whether other behavioral health companies have acted in similar ways.

America’s Health Insurance Plans, a trade group for insurers, would not comment on the specific case but said that health insurers are committed to providing comprehensive coverage of mental and behavioral health services and ensure that parity exists in coverage. But the group pointed to “headwinds when it comes to comprehensive treatment, such as a ... shortage of behavioral health care providers and a lack of reliable quality measures for behavioral health facilities.”

The mental health parity law has been mostly successful in quantitative aspects of insurance coverage, such as copays and deductibles for physical or behavioral health concerns, said Ezra Golberstein, a researcher at the University of Minnesota who studies mental health care policy.

What’s been harder to enforce is parity of “nonquantitative treatment limits,” such as guidelines insurers use when making coverage decisions.

“If this ruling does ultimately hold,” he said, “then I think it helps establish ... what is out of bounds in terms of these nonquantitative limits.”