Grant: Project Grant

Traumatic brain injury (TBI) occurs with an alarmingly high rate and severity in people who are homeless or marginally housed and causes disproportionate damage because brain health is already compromised. Mental illness and addictions are common and are strong risk factors for prolonged symptoms after TBI. For these reasons we believe that TBI may be a primary but underappreciated contributor to chronic impairment in this vulnerable population. As part of a ten-year CIHR-funded study we have been investigating persons at high risk for homelessness. We currently follow over 300 marginally housed persons with monthly assessments for psychiatric symptoms, urine drug screens, detailed substance use history and yearly MRI brain scans. To our knowledge this is one of the most thoroughly characterized large cohort of marginally housed individuals worldwide. Important data we have already gathered indicates that the rate of psychosis is nearly 50% and a history of TBI is the most potent predictor of psychotic illness, strikingly surpassing even stimulant abuse (including methamphetamine). We have also found a synergistic effect of TBI and depression, and a relationship with cognitive impairment. Given the extremely high rate of TBI (31% of this group suffers at least one concussion per year) we expect at least 50 subjects per year who's life trajectory after brain injury can be studied in a uniquely powerful and thorough fashion to accomplish the following aims; (i) Define the relationship between brain injuries and the onset or exacerbation of neuropsychiatric problems and addictions in people who are homeless or tenuously housed and (ii) to discover, with advanced neuroimaging, which brain changes are important in imparting risk for prolonged or poor recovery from TBI. Through our well established links with clinical teams, municipal and provincial government and local police, this data will immediately and meaningfully inform care and social policy.