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Most People Experiencing Homelessness Have Had a Traumatic Brain Injury, Study Finds

A woman in the UK protesting evictions and lack of affordable housing in 2015.
A woman in the UK protesting evictions and lack of affordable housing in 2015.
Photo: Getty Images

A majority of people experiencing homelessness across the world have a history of concussions and other traumatic brain injuries, according to new research out this week. And often, these injuries could have contributed to or been caused by their homelessness, the authors say.


The study, published in Lancet Public Health on Monday, is a review of existing research that looked at how commonly traumatic brain injuries happen among people. It specifically included studies that also took into account people’s housing situation. These studies involved more than 11,000 people who were fully or partially homeless at the time and living in the U.S., UK, Japan, or Canada. And 26 of the 38 originally reviewed studies were included in a deeper meta-analysis.


Taken as a whole, the review found that around 53 percent of homeless people had experienced a traumatic brain injury (TBI) at some time in their lives. Among people who reported how seriously they had been hurt, about a quarter had experienced a moderate to severe head injury. Compared to the average person, the authors noted, homeless people are over twice as likely to have experienced any sort of head injuries and nearly 10 times as likely to have had a moderate to severe one.

“TBI is prevalent among homeless and marginally housed individuals and might be a common factor that contributes to poorer health and functioning than in the general population,” the researchers wrote.

In recent years, scientists have started to document how even mild concussions can have a lasting negative impact on mental health and cognition, particularly among children and teens. And given that anywhere from 51 percent to 92 percent of people in this research reported having their first brain injury before becoming homeless, usually in their teens, it’s likely these injuries played a part in causing their precarious situation. Other times, the increased risk of violence faced by a person experiencing homelessness may have exposed them to these injuries.

In either case, it’s clear that more needs to be done to keep these vulnerable people safe, both before and after they become homeless.


“Collectively, this evidence demonstrates a public health emergency that we already know how to tackle—but have failed to do so,” researcher Rob Aldridge of the University College London in the UK wrote in an accompanying editorial for Lancet Public Health.

Among other things, Aldridge recommended that governments and organizations should make it easier for homeless people to quickly access permanent housing alongside health and social care support to get them back on their feet, while hospitals should stop discharging patients who don’t have a stable place to stay.


In the U.S., it’s estimated that upwards of 500,000 Americans experience homelessness in a given year, a quarter of whom are children.

Science writer at Gizmodo and pug aficionado elsewhere

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Manic Otti

That explains a lot but doesn’t solve anything.  Maybe mandatory helmets for all?