UnitedHealth Group Inc. was sued by the New York State Psychiatric Association and mental health patients over claims the insurer violated laws barring unequal coverage for psychiatric conditions.

UnitedHealth, the largest U.S. health insurer, has maintained “unjustifiably stringent medical-necessity criteria and pre-authorization requirements for mental-health services,” the plaintiffs said in a complaint filed Monday in U.S. District Court in Manhattan.

The company denied or limited access to psychotherapy and other mental health treatment for patients suffering from conditions including psychosis, chronic depression, and anxiety disorders, according to the 102-page complaint, which seeks to represent other customers of the company facing similar situations.

Brad Lotterman, a spokesman for Minnetonka-based UnitedHealth, said in an e-mail that the company recently received the complaint and is reviewing it. “We are committed to helping people with mental-health issues reach long-term recovery,” Lotterman said in the e-mail.

So-called parity laws enacted by Congress and the states of New York and California prohibit insurers from imposing more restrictive limits on care for mental health conditions than for other health-care services, according to the complaint.

Individuals signing on to the suit include a professor at the State University of New York, Stony Brook, a director of marketing for CBS Sports Network, and a marketing associate for a unit of Sysco Corp.

The UnitedHealth policies described in the suit “violate federal and state antidiscrimination laws regarding insurance benefits for mental health and substance abuse disorders,” the plaintiffs alleged.

The insurer also violated the federal Affordable Care Act by failing to continue to pay for the treatment of the patients in the case until final internal appeals were resolved, according to the complaint.

The plaintiffs are seeking damages and an injunction against future discrimination.