Homelessness and Housing-Insecure Populations

Homelessness and housing insecurity describe the situations of people who lack a stable, safe, and adequate place to live — from rough sleeping and emergency shelter to temporary, overcrowded, or precarious accommodation. As a community and public health nursing topic, it concerns the marked health burden associated with unstable housing and the role of housing itself as a determinant of health.

Definition

Homelessness is the condition of lacking stable, safe, and adequate housing, ranging from sleeping rough or in emergency shelters to insecure, temporary, or inadequate accommodation; housing insecurity extends to those at imminent risk of losing housing or living in precarious conditions.

Scope

This entry covers how homelessness and housing insecurity are defined, the patterns of physical and mental ill-health and premature mortality associated with them, the barriers to care this population faces, and housing-led models such as Housing First. It is reference-educational and population-level; it does not provide individual clinical or social-care instructions.

Core questions

• How are homelessness and housing insecurity defined and counted across settings?
• What is the burden of physical illness, mental illness, and substance use among people who are homeless, and how does it affect mortality?
• Why do homeless populations face barriers to accessing health care, and how do those barriers compound illness?
• What does the evidence say about housing-led approaches such as Housing First?

Key concepts

• Definitions and typologies of homelessness
• Housing as a social determinant of health
• Tri-morbidity (physical illness, mental illness, substance use)
• Premature mortality and excess mortality
• Barriers to access and inclusion health
• Housing First and the staircase (treatment-first) model
• Harm reduction

Mechanisms

Unstable housing affects health through exposure to cold, damp, violence, and infection; through disrupted access to food, sanitation, and continuity of care; and through chronic stress. Homelessness, mental illness, and substance use frequently co-occur and reinforce one another, while fragmented services and stigma create barriers to timely care. Housing-led models reverse the traditional sequence by providing stable housing first, without preconditions of treatment or sobriety, on the premise that secure housing is a foundation rather than a reward for clinical stability.

Clinical relevance

For community and public health nurses, this topic explains why people experiencing homelessness present with high and often unmet health needs and why outreach and low-threshold services matter. It is descriptive orientation to a population's needs and the evidence on service models; it is not a protocol for managing any individual's care.

Epidemiology

People experiencing homelessness in high-income countries have substantially higher rates of mental illness, substance use, infectious and chronic disease, and injury than the general population, and markedly elevated mortality, often dying decades earlier than the housed population (Fazel et al., 2014). The co-occurrence of physical illness, mental disorder, and substance use — sometimes termed tri-morbidity — is common and complicates care.

Evidence & guidelines

Fazel and colleagues (2014) synthesised the descriptive epidemiology and policy implications of homelessness in high-income countries. The Housing First model, evaluated in a randomised study by Tsemberis and colleagues (2004) and in subsequent trials, has accumulated evidence for improving housing stability among people with serious mental illness and substance use, and is now reflected in many national homelessness strategies. Definitional and measurement frameworks are discussed in the broader literature (Fitzpatrick et al., 2000).

History

Public-health concern with the health of homeless people has deep roots, but the contemporary evidence base grew from the 1980s onward as visible homelessness rose in many high-income countries. The Housing First approach, developed by Sam Tsemberis and the Pathways programme in New York in the 1990s, challenged the prevailing treatment-first staircase model and reshaped both research and policy in the 2000s and 2010s.

Debates

Housing First versus treatment-first (staircase) models

Housing First provides immediate, unconditional housing with support, whereas staircase models require engagement with treatment or sobriety before housing; evidence favours Housing First for housing stability, while debate continues over outcomes such as substance use and the resources required to scale it.

Key figures

• Sam Tsemberis
• Seena Fazel
• Margot Kushel

Seminal works

• fazel-2014
• tsemberis-2004

Frequently asked questions

Is homelessness only about sleeping on the street?

No. Homelessness spans a spectrum from rough sleeping and emergency shelters to staying temporarily with others, in unstable or overcrowded accommodation, or being at imminent risk of losing housing; many people who are inadequately housed are not visibly on the street.

What is Housing First?

Housing First is an approach that provides stable, permanent housing to people experiencing homelessness without requiring prior treatment or sobriety, then offers support services; it treats secure housing as a starting point for recovery rather than a reward for it.