Nearly two-thirds of Minnesota's homeless population has a mental illness, according to a new study from the Wilder Foundation. The results are based on a survey of nearly 4,300 people experiencing homelessness.

Wilder Research reports more than 10,000 people are homeless in the state today. Of those, some 64 percent of both adults and youth reported having been told by a doctor or nurse within the last two years that they have a mental illness.

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The portion reporting a mental illness has been going up over the last two decades. Wilder has been conducting the one-night survey of people in emergency shelters, transitional housing, and those living outside of shelters every three years since 2000. The first year, some 36 percent of people reported a mental illness, a number that has been steadily increasing. Depression has long been the most common diagnosis reported.

Michelle Decker-Gerrard, senior research manager at Wilder Research and co-director of MN homeless study, says there are likely a number of reasons for the increase. Overall, people reported high numbers of chronic disease, both physical and mental. But Decker-Gerrard thinks people are also more willing to talk about it.

"There may be greater comfort for people to report their own mental health issues," she said. "So there may have always been a higher proportion but some of the stigmatization of that population is getting a little bit better and people are more willing to share that information."

Anxiety is another disorder that has recently been coming up in interviews, in similar numbers to depression. In addition, large numbers of people — nearly three-quarters of adults and more than that for youth — report traumatic childhood experiences, which can exacerbate or lead to mental health problems. And many report continued trauma, of both physical and sexual assaults.

Mental illness can contribute to housing problems. The housing market in the Twin Cities, especially, is very tight, which means that landlords can be extremely picky about whom they rent to.

"The people that tend to get into the rental housing are the people that are higher functioning and have less barriers," Decker-Gerrard said. "The people that have more barriers are the ones that are ending up on the streets or in shelters."

People with mental health problems are more likely to run in to trouble in their housing and to have trouble getting into new housing if they are evicted or are forced out for some other reason.

Wilder expects to have more detailed information about the mental health of the homeless population as it analyzes data over the coming months.