Homelessness is a traumatic experience that can have deeply negative implications for a person’s mental health. At the same time, a person who is struggling to manage a mental illness may be at greater risk of losing their housing because of challenges associated with their condition. For instance, earning the income needed to pay rent may not be possible for someone who has clinical depression and is unable to go to work, someone who has schizophrenia and is unable to maintain organized thought, or someone who has post-traumatic stress disorder and whose body is in a constant state of alert. It is indisputable that homelessness and mental health are related, but it is not a straightforward relationship.

Before you begin this section, we encourage you to take a moment and consider the question of prevalence. What percentage of people who experience homelessness do you think are impacted by mental illness? What mental illnesses do you think are most common amongst people who experience homelessness? Is everyone’s experience of mental illness and homelessness the same? Thinking about these questions helps us to better understand the complex nature of the relationship between homelessness and mental health. We will explore this relationship throughout this section and chapter, but we invite you to use the space below to record your thoughts before moving forward.

This book was written in the fall and winter of 2021, as the COVID-19 pandemic was in its second year and the Omicron variant was emerging. Two years of lockdowns, distancing, and social isolation were weighing heavily on people’s minds. You may be reading this as the pandemic continues, or in a time past as it has come under control. Either way, we ask you to pause for a moment here and reflect on your own mental well-being as well as that of your family and friends. How have you coped with the pressures of living through a global health crisis? What measures have you and your loved ones taken to improve your mental health? What support did you find from your community?

The experience of living through a pandemic and living through homelessness have some commonalities. They are both highly stressful and isolating events, and while people may draw upon their own personal strength and coping skills, their lives are heavily impacted by the decisions government officials make. The pandemic is not a perfectly parallel comparison to homelessness, but it helps to highlight how stress, isolation, and loss of personal agency can lead to poor mental health.

As you reflect on your experience with the COVID-19 pandemic, we encourage you to think about how it has impacted your higher education studies. Even prior to the pandemic, student mental health concerns had been identified as an emergent crisis issue. We begin this section with a look at student mental health, beginning with a video entitled, “Combating the Mental Health Crisis on Canadian Campuses” created by CBC News: The National in October 2017. We then present a video entitled, “Jennifer’s Story: Hope, Courage and Recovery From Mental Illness” about a young woman whose untreated mental illness caused her to leave university in her fourth year of study and subsequently become homelessness.

We begin with the intersection of university students, mental health issues, and homelessness to highlight some important points. First, when we talk about mental health and homelessness, we are not talking about the one-dimensional stereotypes you may have seen in the media, but rather about real people’s lives. Second, while mental illness may be felt at a personal level, by the person who is affected and their loved ones, it is also shaped by broader social factors. This means that even within your own university, the policies that are in place will determine what kinds and how much support are available for students who are struggling with their mental wellness. We invite you now to watch these two videos, about mental health and homelessness, while considering it from a student perspective. Consider while you watch, what supports your university offers and how effective you think they are at buffering against the risk of housing loss.

We began with these two videos as a way of presenting a more complex image of mental illness and homelessness than is commonly shown in movies and on television. You likely have seen the images of someone who is experiencing severe psychosis, such as hearing voices, and is sleeping outside in public spaces. Certainly, this is some people’s experience. However, we want you to approach this chapter with a much broader perspective. In framing the question for this section, we asked about the prevalence of mental health issues, rather than mental illness. This was done intentionally, with the recognition that mental illnesses are diagnosed through clinical assessment, whereas mental health issues are more broadly defined. A person may not have a clinical diagnosis but may still not be mentally well. We wanted to capture the full spectrum in posing this question.

What we found was that there is no clear answer to this question. What is the prevalence of mental health issues for people experiencing homelessness? No one knows. What is clear, is there is no precise accounting of mental illness rates, but that it is higher than the general public. When we asked homelessness researchers who specialize in mental health about the prevalence, they explained that the rates differ depending on a range of factors, such as which conditions are included in the estimate. For instance, if we are talking about diagnosed severe mental illness, the rates are lower than if we expand the question to consider people who may not have a diagnosis but are nonetheless mentally unwell. In the next two videos, Dr. Tim Aubry and Dr. Nick Kerman explain how the estimates vary depending on the parameters used.

Substance use is common amongst people who have mental illness and are experiencing homelessness, often as a form of self-medicating and trying to cope with hardships. The research shows a complex relationship between mental illness, substance use, and homelessness. For instance, Gicas et al., (2021) questioned whether there is a connection between psychosis in adults experiencing homelessness and the age at which they first used cannabis. They conducted research in Vancouver’s Downtown Eastside using surveys and a battery of neurocognitive tests including the use of structural and diffusion tensor imaging MRI scans. They found that early cannabis exposure (prior to age 15) was associated with an increased risk of developing substance induced psychosis and that later first-usage increased the risk of developing schizophrenia or schizoaffective disorder. Further, the results also indicated that early cannabis exposure may result in changes in regional brain volume (Gicas et al., 2021).

Another study from Vancouver was conducted to examine whether patterns of substance use and risk behaviours were associated with specific psychiatric disorders amongst people who had experienced homeless (Vogel et al., 2019). The results showed a complex picture. They found that major depressive disorder was associated with the use of stimulants and benzodiazepines, post-traumatic stress disorder (PTSD) was associated with stimulant use, panic disorder was associated with alcohol and benzodiazepine use, opioid use was less common in participants with a psychotic disorder, injection drug use occurred more frequently among participants with major depressive disorder, PTSD, and mood disorder with psychotic features (Vogel et al., 2019). These findings are important because they show us that while substance use may commonly co-occur with mental illness amongst people experiencing homelessness, it is not a straightforward relationship.

In another study, a sample of 1,585 people experiencing homelessness were assessed for alcohol and/or substance dependence and bipolar disorder, unipolar depression, and psychotic disorder to better understand whether relationships existed between these conditions (Maremmani et al., 2018). The researchers found that alcohol and/or substance dependence was more common amongst those who were younger, of Indigenous ancestry, lower educated, and located in Western Canada. The odds of alcohol and/or substance dependence were higher among those affected by bipolar disorder, and unipolar depression to a lesser extent. This study shows that people experiencing homelessness who have a major mental illness are at high risk of concurrent alcohol and/or substance dependence but that there are factors such as diagnosis, ethnicity, and location that need to be considered (Maremmani et al., 2018). We invite you now to learn more about this study – and the relationship between substance use, mental illness, and homelessness – in this section’s featured reading below.

The prevalence of mental health issues among people experiencing homelessness is difficult to determine, in large part because substance use is a complicating factor. Concurrent mental health and substance use disorders are highly prevalent for people experiencing homelessness. In a study from British Columbia, researchers used a range of assessments with 500 individuals living in shelters or on the street and categorized participants into four groups: (1) those without any current mental disorder, (2) those with substance use disorders only, (3) those with substance use disorders only, and (4) those with concurrent substance use and mental disorders (Schütz et al., 2019). Results showed that those with dual diagnoses report more severe physical and psychological symptoms, and these individuals were more likely to be younger, Indigenous, and to be unsheltered. Importantly, they also reported significantly more challenges receiving the health care services they need. This group, with both mental illness and substance use disorders, is highly vulnerable because they lack access to basic services, like health care and shelter, despite having some of the most complex needs (Schütz et al., 2019).

This population’s inequitable access to mental health services is another key reason we lack definitive rates of mental health issues. If we were to only account for those with diagnosed mental illnesses, the rates would be considerably lower than if we consider poor mental health more generally. Although many people would qualify as meeting the criteria for mental illness, their lack of access to mental health professionals makes those diagnoses and treatments less likely. There are many complicated reasons why people who experience homelessness have inequitable access to health care, as we discuss further in the chapters on Primary Care & Nursing and Emergency Medicine, but a lack of communication, discrimination, and stigma are key drivers for these poor outcomes.

The exact prevalence of mental health issues for people experiencing homelessness is unknown, in part because of different considerations about what is included and in part because these individuals often lack access to mental health services that could provide diagnoses and treatments. We have seen a range of different estimates throughout this section so far, with researchers identifying studies that show figures as low as 10% and as high as 75%.

When we set out to write this book our mission was to explore seemingly simple questions that had complex answers. The prevalence of mental health issues is no exception. Homelessness, poor mental health, and substance use are often connected, but not in straightforward nor singular ways. People may experience a mental illness that results in housing loss, or they may be experiencing homelessness and find that their mental well-being declines as a result. In the next video Dr. Sean Kidd, Chief of the Psychology Division at the Centre for Addiction and Mental Health in Toronto, explains that when we take a broad view, we see that nearly every person who experiences homelessness will have mental health challenges because of the associated stress, violence, and trauma.

Dr. Sean Kidd: What is the prevalence of mental health issues for people who experience homelessness?

In this video, Dr. Sean Kidd explains that there are different estimates of mental illness prevalence for people experiencing homelessness, based on what is included in the definition. When considering major mental health disorders, such as major depression, PTSD, schizophrenia, and the overlay of addictions, it is estimated that this impacts 50% of people experiencing homelessness. When extended to general mental well-being, nearly every person who has experienced homelessness for a period of time will have mental health challenges, large amounts of stress, and experiences of violence. Dr. Kidd argues that homelessness is traumatizing, not in a single event kind of way, but as an everyday, ongoing form of deprivation. This video is 1:56 in length and has closed captions available in English.

Dr. Cheryl Forchuk: What is the prevalence of mental health issues for people who experience homelessness?

In this video, filmed at a hospital during the COVID-19 pandemic, Dr. Cheryl Forchuk makes the argument that the homeless population should be treated as a disenfranchised mental health population. In one study 187 youth experiencing homelessness were given proper assessments, and 100% were diagnosed with mental health and/or addictions issues. Dr. Forchuk argues that not every person is comfortable revealing their situation, and so it is better to provide everyone experiencing homelessness with mental health and addictions supports than to miss people who may benefit. This video is 1:23 in length and has closed captions available in English.