The nation's largest health insurer is once again staring down accusations that it is discriminating against customers who seek coverage for mental health services.

The mother of a 13-year-old boy diagnosed with autism spectrum disorder is suing UnitedHealthcare and its subsidiary United Behavioral Health on behalf of a potential class of policyholders whose self-funded plans exclude coverage of "Intensive Behavioral Therapy."

The intensive therapy exemption includes applied behavioral analysis (ABA), the foremost treatment for autism, according to the complaint filed Thursday in the U.S. District Court for the Northern District of California. The exemption contradicts an announcement UnitedHealthcare made in 2017, promising to extend its coverage of the therapy to all fully insured health plans.

The Jane Doe plaintiff alleges the exemption in her self-funded plan violates the Paul Wellstone and Pete Domenici Mental Health Parity and Addiction Equity Act of 2008.

"Categorically excluding coverage for ABA makes it harder if not impossible for autistic children to retain the form of treatment that has proven to be most effective for their condition, even though they have insurance that purports to cover autism," said plaintiffs counsel Caroline Reynolds of Zuckerman Spaeder in Washington, D.C. "This is exactly the sort of discrimination against mental health coverage that the Parity Act is supposed to eliminate."

Reynolds said she expects to prove in court that UBH is enforcing the exclusions because it helps increase or retain self-funded clients, who are companies that administer health benefits themselves instead of purchasing policies from insurers, which represent 70% of UBH's business.

A UnitedHealth representative did not respond to a request for comment at the time of publication.

Meiram Bendat of Psych-Appeal Inc. in West Hollywood, California, also represents Doe alongside Zuckerman Spaeder's Brian Hufford and Jason Cowart in New York and Rachel Cotton in Washington, D.C.

This isn't Psych-Appeal and Zuckerman Spaeder's first go at UnitedHealthcare. The duo earned a major victory in March when U.S. Magistrate Judge Joseph Spero of the Northern District of California found the company emphasized cost-cutting in its guidelines for mental health and addiction coverage.

Doe is suing on claims of breach of fiduciary duty and asking the court to enjoin UBH and UnitedHealthcare from enforcing the intensive behavioral therapy exclusions.