Jack Tsai, PhD

With a lifetime and 1-year prevalence of homelessness in the US population found to be 4.2% and 1.5%, respectively, and the total number of people who experience some form of homelessness over the course of a year is estimated to be 2.5 to 3.5 million individuals, homelessness is a serious problem. Mental illness, in addition to adverse childhood experiences and substance use, are risk factors for homelessness. Although estimates of the prevalence of mental illness vary, studies looking at mental illness in the homeless population have generally found a high prevalence of mental disorders. The most common disorders may be alcohol and drug dependence (

There is clearly a link between psychiatric disorders and homelessness; disentangling the nature of this relationship is complicated. Regardless of mental health status, people who are homeless generally have a history marked by poverty and social disadvantage, including considerable poverty in childhood and lower levels of education, and they are likely to belong to an ethnic minority.

 Mental illness had preceded homelessness in about two-thirds of the cases.

Homelessness in turn has been associated with poorer mental health outcomes and may trigger or exacerbate certain types of disorders. For example, findings indicate that homelessness is related to higher levels of psychiatric distress and lower perceived levels of recovery from serious mental illness.

Impact of homelessness on premature morbidity

Homelessness is associated with substantially increased morbidity and mortality from many causes including infectious diseases, cardiovascular disease, cancer, unintentional injury, suicide, homicide, and substance use. The unsheltered homeless have an even greater burden, with higher mortality than sheltered homeless. Among a large group of homeless adults in Boston, disparities in deaths attributed to tobacco, alcohol, and drug use accounted for almost 60% of the mortality gap between homeless adults and the general population.

In accordance with findings in the general population, there also is a strong association between psychiatric disorders and suicide in homeless populations. The prevalence of suicidal ideation and suicide attempts is extremely high in mentally ill homeless persons. In a large sample of homeless adults with serious mental illness, almost 8% reported a suicide attempt within the previous 30 days.

 The highest rates of suicidal ideation and suicide attempts were in the group aged 30 to 39 years, in contrast to the general population with peaks of suicidality in young adults and the elderly.

General guidelines were created for primary care physicians working with the homeless in the US in 2004, and in 2018 the Street Medicine Institute began publishing international clinical guidelines targeting the primary care needs of specifically street-dwelling homeless individuals.

 Unfortunately, similar guidelines for psychiatrists working with the street-homeless population are still lacking.

When thinking about challenges to accessing care, it is critical to understand the heterogeneous nature of homelessness. The structures of support and oppression for each individual may vary significantly based on the surrounding community and resources.

Fundamental basic needs. A qualitative study highlighted the basic human needs that often take priority over seeking psychiatric care.

 Access to adequate nutrition, water, shelter, and protection from the elements are the reality homeless individuals encounter daily, and these issues take priority over psychiatric needs, which are often not addressed until a crisis occurs.

The effects of illness. Having mental health care needs itself may be a barrier to accessing psychiatric care. Motivation to make and attend appointments may be low if an individual is suffering from depression, amotivation, anhedonia, anxiety, paranoia, hypervigilance, history of trauma, substance use, or negative past experiences with the health care system related to mental illness. Moreover, homeless people may have experienced greater trauma, have traumatic brain injuries, and cognitive impairment-all of which may affect interactions with the health care system and health literacy.

Similarly, comorbid medical illness may be a barrier, as these needs may take priority over psychiatric care. Many homeless people have medical issues such as diabetes, hypertension, tuberculosis, and ischemic heart disease. These needs often necessitate resources such as intensive case management and assertive outreach to maintain treatment.

 Homeless individuals often lack adequate transportation; consequently they are unable to do the necessary tasks involved in care-getting laboratory work completed, picking up medications, and getting to mental health appointments. Public transportation may not always be a solution, as it often requires multiple transfers, can be unreliable and, in some areas, may be limited or may not exist. Most significantly, homeless individuals may lack the resources to pay for fares.

 For persons who are homeless, small expenses can be a significant barrier to accessing mental health care. Moreover, they may not be cognizant of resources available to them through Medicaid or the Affordable Care Act.

 Although some homeless adults and youth have access to cell phones, there is higher turnover of both phones and phone numbers, which can pose a barrier to consistent communication. Keeping a cell phone charged is a challenge for those without reliable access to electricity. Similarly, with lower internet use, homeless people are likely to have less access to important information, including care and resources. Language barriers may also affect access to care, particularly in limited resource settings.

 Stigma and discrimination continue against homeless individuals who also have mental health conditions. Setting health care goals may feel unattainable when pressing issues like basic survival are more salient. Homeless people with mental illness are also highly vulnerable to violence, with a reported lifetime incidence of 74% to 87% of violence being perpetrated against them.

 Psychiatric care may include prescribed psychotropics that affect alertness and pose a danger for someone who is at increased risk for victimization and violence. Furthermore, those who have a history with the legal system, reintegrating into society, parole, or strained finances may further impact their ability to acquire care.

Briefly, solutions to the problem of homelessness include finding and implementing innovative models of care such as street psychiatry, integrated primary care, and mental health care models; Veterans Administration Homeless Models (Homeless Patient Aligned Care Teams H-PACT); and utilizing allies in the housing and rehabilitation services domains to find specialized housing opportunities. Taking a team-based approach is essential, as the mental health care needs of homeless people are often complex and include many aspects of the social determinants of health. Multidisciplinary teams often include case managers, social workers, housing specialists, and vocational specialists. Medical students can also play an integral part in providing mental health care for homeless persons. (For a full and detailed list of potential solutions, please see

Recovery models and holistic, patient-centered, trauma-informed care are important as perceived discrimination, stigma, and distrust may be present. Communication barriers must also be addressed. This includes the advance development of plans regarding communications and finding creative ways to address potential barriers. Solutions should be tailored to fit the individual needs of the patient, including special needs that may occur around patients with dual diagnoses, women, families, and children. Although beyond the scope of this article, effective public policy can play a role in reducing homelessness.

Mental health conditions are highly prevalent in homeless populations. Although homeless individuals have higher mortality related to many causes, access to care is poorer than that for the general population. Further research and advocacy are needed to address the obstacles that homeless individuals encounter in accessing mental health care.

Dr Balasuriya is a Medical Resident and Dr Buelt is an Instructor, Department of Psychiatry, Yale University School of Medicine, New Haven, CT; Dr Tsai is Campus Dean and Professor, School of Public Health, University of Texas Health Science Center, Houston, TX. The authors report no conflicts of interest concerning the subject matter of this article.

1. Fazel S, Khosla V, Doll H, Geddes J. The prevalence of mental disorders among the homeless in western countries: systematic review and meta-regression analysis. 

2. Sullivan G, Burnam A, Koegel P. Pathways to homelessness among the mentally ill. 

3. Castellow J KB, Townley G. Previous homelessness as a risk factor for recovery from serious mental illness. 

4. Baggett TP, Chang Y, Singer DE, et al. Tobacco-, alcohol-, and drug-attributable deaths and their contribution to mortality disparities in a cohort of homeless adults in Boston. 

5. Prigerson HG, Desai RA, Liu-Mares W, Rosenheck RA. Suicidal ideation and suicide attempts in homeless mentally ill persons: age-specific risks of substance abuse. 

6. Bonin E, Hoeft J, Brehove T, et al. General Recommendations for the Care of Homeless Patients. 

7. Board of Directors, Street Medicine Institute. Street Medicine Clinical Guidelines, 2018.

8. Paudyal V, MacLure K, Buchanan C, et al. “When you are homeless, you are not thinking about your medication, but your food, shelter or heat for the night”: behavioural determinants of homeless patients’ adherence to prescribed medicines. 

9. Roy L, Crocker AG, Nicholls TL, et al. Criminal behavior and victimization among homeless individuals with severe mental illness: a systematic review. 

10. O’Toole TP, Johnson EE, Aiello R, et al. Tailoring care to vulnerable populations by incorporating social determinants of health: the Veterans Health Administration’s “Homeless Patient Aligned Care Team” program. 

Articles

Mental health conditions are highly prevalent in homeless populations. Further research and advocacy are needed to address the obstacles that homeless individuals encounter in accessing mental health care.

Jack Tsai, PhD

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The Never-Ending Loop: Homelessness, Psychiatric Disorder, and Mortality