FRIDAY, Jan. 15 (HealthDay News) -- Black men in the United States are misdiagnosed with schizophrenia at least five times more often than any other racial group.

This trend dates back to the 1960s and 1970s, when equal rights activism was equated with mental illness, said researcher Jonathan Metzl, an associate professor of psychiatry and women's studies at the University of Michigan, and director of U-M's Culture, Health and Medicine Program.

He analyzed archives at the Ionia State Hospital for the Criminally Insane and found that black men, mainly from Detroit during the civil rights era, were taken to the facility and often misdiagnosed with schizophrenia.

"Some patients became schizophrenic because of changes in their diagnosis rather than their clinical symptoms," Metzl said in a U-M news release.

He noted that the way schizophrenia was defined by the psychiatric profession changed in the 1960s and 1970s. It had been considered an illness affecting non-violent white patients, but the language was changed to violent, hostile, angry and aggressive as a way to label black men.

"It's an easy thing to say this was racism, but it's a much more complicated story -- that's still playing out in present day," he added.

The criminalization of mental illness and misdiagnosis of schizophrenia meant that many black men have been placed in prisons rather than psychiatric hospitals, Metzl said. He noted that the Ionia facility became a prison in 1977.

Over-diagnosis of schizophrenia in black American men continues despite efforts to improve cultural competency training in psychiatry.

"Multicultural training is important, but it often does little to address how assumptions about race are structurally embedded into health care delivery systems," Metzl said.

His research appears in a new book, The Protest Psychosis: How Schizophrenia Became a Black Disease.

More information

Mental Health America has more about schizophrenia.