CHICAGO, May 23 (Xinhua) -- African Americans living in the Great Lakes state of Michigan report a decline in mental health as their socioeconomic status rises, a study of the University of Michigan (UM) shows.

The study utilized data from Michigan's 2017 State of the State Survey conducted by the Institute for Public Policy and Social Research at Michigan State University. For the survey, participants must be over 18 years old, speak English, reside in Michigan and not be institutionalized.

The study included a sample of about 1,000 participants and looked at how self-reported mental health changed across 11 income levels. In general, self-reported mental health increased as people moved up socioeconomic levels.

"The group is climbing the social ladder but is still depressed," said lead author Shervin Assari, research assistant professor at the Center for Research on Ethnicity, Culture, and Health in the UM School of Public Health.

"Given my previous research, I am not shocked by the results," Assari said, "I have seen high-economic-status blacks being more depressed and reporting more discrimination ... You expect social economic status to protect you. You expect income to equally protect all populations but that is not what you find at the national level and not in Michigan, either."

The study, posted on UM website Wednesday, has been published in Behavioral Sciences.