(Reuters Health) – Men and women who suffered traumatic brain injury (TBI) had more than twice the risk of winding up in a federal prison in Canada as their uninjured peers, a new study found. That doesn’t surprise Dr. Geoffrey Manley, a neurosurgeon who runs a trauma center. He knows all too well the long-term struggles of survivors of TBI.

“Because there’s no system of care for these individuals, they fall into the cracks and get themselves in trouble. And we really as a society are not doing a good job of taking care of people with traumatic brain injuries,” Manley, who was not involved in the study, said in a phone interview.

For 13 years, researchers followed more than 1.4 million people who were eligible for health care in Ontario, Canada and were between the ages of 18 and 28 in 1997. As reported in CMAJ Open, the research team linked subjects’ health records to correctional records, adjusted for a variety of factors like age and substance abuse, and found that men with TBI were 2.5 times more likely to serve time in a Canadian federal prison than men without TBI.

For women with TBI, the risk of winding up in a Canadian federal prison was 2.76 times higher than it was for women without TBI, although the authors caution that the pool of incarcerated females was small, accounting for only 210 of the more than 700,000 women studied.

“Some people might think women might be less likely to be incarcerated with a traumatic brain injury than men, but they’re just as likely,” senior author Flora Matheson said in a phone interview.

Matheson, a medical sociologist with the Center for Urban Health Solutions at St. Michael’s Hospital in Toronto, said the study’s results could be just “the tip of the iceberg” of a connection between brain trauma and imprisonment, because the study included only prisoners in federal Canadian correctional facilities and only serious TBI. It excluded prisoners detained in Canadian provincial jails as well as those who suffered mild TBI.

Manley, who is also a professor at the University of California, San Francisco, suspects that half of those who suffer trauma to the brain never seek medical care and their injuries therefore go undetected and unconsidered in studies.

“We’re not even identifying these traumatic brain injuries, and we sure aren’t treating them, and it is a perfect storm for these people falling off the rails,” he said.

Six months after suffering a TBI, many patients still feel depressed and anxious and some struggle with aggression and substance abuse, Manley said. “A substantial number of people seen in emergency departments with traumatic brain injuries” don’t get follow-up care afterward, he said. “So we should not be surprised that we’re seeing people who are unemployed, incarcerated.”

Matheson pointed out that her study shows an association, not a causal relationship, between TBI and incarceration. More research is needed to determine how the injuries and imprisonment connect, she said.

In 2010, TBIs were diagnosed in 2.5 million Americans, according to the U.S. Centers for Disease Control and Prevention. Over the past decade, rates of visits to U.S. emergency departments for TBI rose 70 percent, the CDC estimates.

Manley attributes the increase to greater awareness about concussions in sports but said brain injuries are just as likely to occur as a result of slips and falls. Prior studies suggested links between TBI and criminal justice involvement but the findings were not all statistically significant, the authors write. The new study is one of the largest of its kind and the first to examine the association in Canada.

Matheson called for more screening for TBI in prisoners and said correctional programs should recognize that people with brain injuries may have memory lapses and trouble sitting still. Manley stressed the need for increased awareness about the potential for debilitating long-term fallout from TBI. “There’s probably a huge hidden cost to society here, not to mention the cost to individuals and their families,” he said.