Particularly within the context of poverty and the lack of afforable housing, certain additional factors may push people into homelessness. Other major factors which can contribute to homelessness include the following:
    Lack of Affordable Health Care: For families and individuals struggling to pay the rent, a serious illness or disability can start a downward spiral into homelessness, beginning with a lost job, depletion of savings to pay for care, and eventual eviction. In 1997, approximately 43.4 million Americans had no health care insurance (U.S. Bureau of the Census, 1998b). More than a third of persons living in poverty had no health insurance of any kind. The coverage held by many others would not carry them through a catastrophic illness.
    Domestic Violence: Battered women who live in poverty are often forced to choose between abusive relationships and homelessness. In a study of 777 homeless parents (the majority of whom were mothers) in ten U.S. cities, 22% said they had left their last place of residence because of domestic violence (Homes for the Homeless, 1998). In additions, 46% of cities surveyed by the U.S. Conference of Mayors identified domestic violence as a primary cause of homelessness (U.S. Conference of Mayors, 1998).
    Mental Illness: Approximately 20-25% of the single adult homeless population suffer from some form of severe and persistent mental illness (Koegel et al, 1996). 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 (Federal Task Force on Homelessness and Severe Mental Illness, 1992). However, 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.
    Addiction Disorders: 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. During the 1980s, competition for increasingly scarce low-income housing grew so intense that those with disabilities such as addiction and mental illness were more likely to lose out and find themselves on the streets. The loss of SRO housing, a source of stability for many poor people suffering from addiction and/or mental illness, was a major factor in increased homelessness in many communities.
    Addiction does increase the risk of displacement for the precariously housed; in the absence of appropriate treatment, it 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. 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. 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 (National Coalition for the Homeless, 1998).
    Even when disabling conditions such as addiction or mental illness are treated, homeless addicts and mentally ill people must compete with all other poor people for a dwindling supply of low-income housing. Homelessness can thus be seen as a perverse game of musical chairs, in which the loss of "chairs" (low cost housing) forces some people to be left standing (homeless). Those who are least able to secure a chair -- the most disabled and therefore the most vulnerable -- are more likely to be left without a place to sit.