An Underappreciated Link: Brain Injury, Homelessness, and Addiction

Brain injury, homelessness, and addiction –  regardless of which occurs first, experiencing just one increases the odds of experiencing the other two.  In fact, the percentage of homeless people who have suffered a brain injury may be seven times higher than the general population1, and 20% of people who do not have a pre-existing substance abuse problem become vulnerable to substance abuse after a brain injury2.  Supporting this data is one study of 111 homeless men aged 27 to 81 years old living in a shelter in downtown Toronto3.  45% of these men had experienced a traumatic brain injury (TBI) and, of these, a staggering 87% experienced at least one TBI before becoming homeless.  64% had a lifetime history of substance abuse.  In a similar study of 904 homeless men and women, the lifetime prevalence of TBI was 53% and compared to those without a history of TBI, participants with a TBI had a significantly higher prevalence of alcohol and drug problems (42% vs 28% and 57% vs 40%, respectively)4.

One can theorize numerous explanations that link brain injury, homelessness, and addiction to each other.  For example, survivors of TBI may struggle with various health issues including anxiety, depression, insomnia and pain, and they may self-medicate to cope with these issues5.  Some research reports that, of people who experience a TBI, 68% already have a history of substance misuse and 50% return to pre-injury consumption levels after the injury6.  Dependence on drugs may result in unemployment or criminal behaviour that leads people to living on the streets.  Alternatively, an individual forced into homelessness due to unescapable debt or a lack of support may get mixed up with the wrong crowd and start using drugs as a way of life.  A lack of self-control or judgment, or the wrong run-in with someone on the street, could result in them being assaulted and sustaining a brain injury that further exacerbates their living situation.

Evidently, while the cognitive effects of brain injury may augment the risk of experiencing mental health or substance problems, it is equally plausible that a pre-existing mental health or substance problem augments the risk of experiencing a brain injury4.  Furthermore, homelessness can present as both a cause and a consequence of TBI.  Therefore, it is imperative that we recognize the substantial interplay of brain injury, homelessness, and addiction, and how these conditions can affect anyone’s quality of life and functioning within our society.  In order to provide adequate care and support for patients, health care providers should assess for TBI in all homeless individuals and recognize that symptoms of brain injury and substance abuse can present in indistinguishable ways2.  They must also appreciate why the effects of brain injury can prevent patients from successfully adhering to substance abuse treatment programs to hopefully better assist them in achieving stable and sustainable housing off the street.  Understandably, patients who battle these three conditions concurrently are highly complex, and they require comprehensive management of each condition with appropriately tailored resources and multi-faceted interventions.


  1. Michael’s Hospital Newsroom. (2014, April 25). Study finds almost half of homeless men had traumatic brain injury in their lifetime, vast majority before they lost their homes. Retrieved from:
  2. James, D; Jarrett, M; Bhalerao, S; Courtney, C . (2001). Ontario Neurotrauma Foundation. Brain Injury and Substance Abuse: The Cross-Training Advantage (online manual).
  3. Topolovec-Vranic, J; Ennis, N; Howatt, M; Ouchterlony, D; Michalak, A; Masanic, C; et al. (2014). Traumatic brain injury among men in an urban homeless shelter: observational study of rates and mechanisms of injury. CMAJ Open 2(2):E69-E76.
  4. Hwang, S; Colantonio, A; Chiu, S; Tolomiczenko, G; Kiss, A; Cowan, L; et al. (2008 October). The effect of traumatic brain injury on the health of homeless people. CMAJ 179(8):779-84.
  5. The Cridge Centre for the Family. (n.d.). Mental health, addiction, and brain injury. Retrieved from:
  6. Brain Injury Australia. (n.d.). Fact Sheet 3: The connection between acquired brain injury and homelessness. Retrieved from:

Written By: Amy Semaka

Amy Semaka is a graduate from the University of Alberta and holds both a Bachelor of Pharmacy and a Doctor of Pharmacy degree.  She currently works in Edmonton’s inner city where she provides care for patients with drug addictions and issues related to homelessness, and also for a family medicine clinic where she provides comprehensive care to patients with chronic medical conditions.