UnitedHealth Group faces a lawsuit that accuses the health insurer of illegally denying mental health and addiction benefits to maximize profits. The class-action lawsuit, filed Sept. 12 by law firm Napoli Shkolnik on behalf of three mental health and addiction treatment facilities, claims the treatment centers provided millions of dollars in unreimbursed care to members of UnitedHealth's behavioral health unit, United Behavioral Health. Specifically, the three plaintiffs allege they had 157 patients with more than 2,000 claims that were illegally denied by United Behavioral Health. The plaintiffs said the amount of denied claims for them alone totals $5 million, while denied claims for the entire class could exceed $9.3 billion.