Universal Health Services Inc., of King of Prussia, is pushing further into behavioral health, announcing Monday that it had agreed to pay $500 million in cash for Ascend Health Corp., which operates eight inpatient psychiatric hospitals and one substance-abuse treatment center. The planned acquisition, which includes facilities in Texas, Arizona, Utah, Oregon, and Washington, builds on Universal Health Services' $3.1 billion purchase of Psychiatric Solutions Inc. in November 2010. That deal made Universal Health Services (UHS) the nation's largest provider of behavioral-health services, according to the company.