Half of all homeless individuals may have suffered a traumatic brain injury at some point in their life, raising questions about whether the injury is consequence or even a cause of their homelessness. According to The Guardian, a Lancet study compiling research from Australia, Canada, Japan, South Korea, the U.K. and the U.S. found that 53 percent of the homeless population had suffered a traumatic brain injury—which could lead to neurological or psychiatric disorders if severe enough. That figure was 2.3 to four times the rate of the general population. The study—published in the Lancet Public Health Journal—also found that a fourth of homeless individuals had moderate to severe traumatic brain injuries, or 10 times the rate found in the general population. “The relationship between homelessness and TBI could function both ways—TBI could increase the risk of homelessness, and homelessness could increase the risk of TBI,” researcher Jehannine Austin said. “We need a better understanding of this relationship to address the issue, and to improve outcomes in the homeless and marginally housed population.”