Miami Homelessness - Warren Richardson Photography

Homelessness is defined as living in housing that is below the minimum standard or lacks secure tenure. People can be categorized as homeless if they are: living on the streets (primary homelessness); moving between temporary shelters, including houses of friends, family and emergency accommodation, living in private boarding houses without a private bathroom or security of tenure. The legal definition of homeless varies from country to country, or among different jurisdictions in the same country or region.

People who are homeless are most often unable to acquire and maintain regular, safe, secure and adequate housing due to an unsteady or lack of income. Homelessness and poverty are interrelated. There is no methodological consent on counting the homeless and identifying their special needs; thus in most cities only estimated homeless populations are known.

Homelessness and poverty are inextricably linked. People who are poor are frequently unable to pay for housing, food, child care, health care, and education.

While the number of poor people has decreased a bit in recent years, the number of people living in extreme poverty has increased. In 2000, 39% of all people living in poverty had incomes of less than half the poverty level. This statistic remains unchanged from the 1999 level.

Approximately 22% of the single adult homeless population suffers from some form of severe and persistent mental illness.

An in-depth study of 13 communities across the nation revealed service gaps in every community in at least one stage of the treatment and recovery continuum for homeless people. Source: National Coalition for the Homeless

Difficult choices must be made when limited resources cover only some of these necessities. Often it is housing, which absorbs a high proportion of income, that must be dropped. Being poor means being an illness, an accident, or a paycheck away from living on the streets.

The relationship between addiction and homelessness is complex and controversial. While rates of alcohol and drug abuse are disproportionately high among the homeless population, the increase in homelessness over the past two decades cannot be explained by addiction alone. Many people who are addicted to alcohol and drugs never become homeless, but people who are poor and addicted are clearly at increased risk of homelessness.

In the absence of appropriate treatment, addiction may doom one's chances of getting housing once on the streets. Homeless people often face insurmountable barriers to obtaining health care, including addictive disorder treatment services and recovery supports.

Despite the disproportionate number of severely mentally ill people among the homeless population, increases in homelessness are not attributable to the release of severely mentally ill people from institutions. Most patients were released from mental hospitals in the 1950s and 1960s, yet vast increases in homelessness did not occur until the 1980s, when incomes and housing options for those living on the margins began to diminish rapidly.

According to the Federal Task Force on Homelessness and Severe Mental Illness, only 5–7% of homeless persons with mental illness need to be institutionalized; most can live in the community with the appropriate supportive housing options.

Domestic violence is the second leading cause of homelessness among women. Battered women who live in poverty are often forced to choose between abusive relationships and homelessness. Nationally, approximately half of all women and children experiencing homelessness are fleeing domestic violence.

Many mentally ill homeless people are unable to obtain access to supportive housing and/or other treatment services. The mental health support services most needed include case management, housing, and treatment.

Most people who experience homelessness (83%) are homeless for a short period of time, and usually need help finding housing or a rent subsidy.

The following are among the obstacles to treatment for homeless persons: lack of health insurance; lack of documentation; waiting lists; scheduling difficulties; daily contact requirements; lack of transportation; ineffective treatment methods; lack of supportive services; and cultural insensitivity.

A small portion (17%) is homeless for long periods of time or cycle in and out of homelessness. They need permanent supportive housing.

In 2005, an estimated 100 million (1 in 65 at the time) people worldwide were homeless and as many as 1 billion people live as squatters, refugees or in temporary shelter, all lacking adequate housing. Historically in the Western countries, the majority of homeless have been men (50–80%), with single males particularly overrepresented. In 2015, the United States reported that there were 564,708 homeless people within its borders, one of the higher reported figures worldwide. These figures are likely underestimates as surveillance for the homeless population is challenging.