A federal trial judge has certified a class action filed against Blue Shield of California and Magellan Health Inc. for systematically restricting insurance coverage for mental health and substance abuse treatment.

In her June 15 order, U.S. District Judge Lucy Koh of the Northern District of California granted class certification for Employment Retirement Income Security Act group plan members whose claims for residential and intensive outpatient mental health and substance abuse treatment were rejected by insurer Blue Shield and health care provider Magellan based on the companies' “medical necessity criteria guidelines” from Jan. 1, 2012, to the present.

It's the latest victory in a niche market dominated by a handful of health care plaintiffs lawyers who go after insurers for disparate treatment of behavioral health issues in violation of ERISA and depending on the case, the Mental Health Parity and Addiction Equity Act of 2008.