A new federal study finds that about one in four adults admitted to community hospitals have a mental-health or addiction diagnosis.

The Agency for Healthcare Research and Quality report found that 7.6 million out of 32 million hospital stays by Americans ages 18 and older involved mental illness or alcohol or other drug disorders. Of these, 1.9 million had a primary diagnosis of addiction or mental illness.

Patients dually diagnosed with addiction and mental illness accounted for about 1 million community-hospital stays.

Medicare paid for about half the stays, while 18 percent were paid for by Medicaid. About 8 percent of patients were uninsured; the rest were covered by private insurers.

The report also noted that about one third of all hospital stays by uninsured patients involved addiction or mental-health problems.

"The significant number of hospital stays related to mental-health and substance-use disorders signals the need for an increased national effort to identify and intervene early before the conditions require a hospital stay," said Terry Cline, Ph.D. , administrator of the federal Substance Abuse and Mental Health Services Administration.

"Too often because of social stigma or lack of understanding, individuals and health care providers don't recognize the signs or treat mental health or substance use disorders with the same urgency as other medical conditions."