In January 2013, there were a total of 610,042 homeless people in the US (Henry, Cortes & Morris, 2013). 394,698 of the homeless individuals lived in sheltered locations while 215,344 of them lived in unsheltered locations (Henry et al., 2013). According to the US Conference of Mayors (2008), the leading causes of family homelessness in 25 cities surveyed include lack of affordable housing (72%), poverty (52%), unemployment (44%), and low-paying jobs (36%). For single adults, the leading causes of homelessness are substance abuse (68%), lack of affordable housing (60%), mental illness (48%), and poverty (44%) (US Conference of Mayors, 2008). There are multiple pathways to homelessness, but some individuals may be more predisposed to it than others because of biological and social factors.
Biological Factors of Being Homeless
Substance abuse was identified as the leading problem of homelessness in single adults in 68% of the cities surveyed by the US Conference of Mayors (2008). Although substance abuse is considered a psychological disorder, research suggests that some people have biological predispositions towards substance addiction. The study by Yoo et al. (2012) found that the activity of the gene NrCAM and addictive behavior have a strong correlation, which indicates that substance abuse probably has a genetic foundation.
Most epidemiological studies suggest that genetic factors have an important role in substance addiction development, but it is also important to consider that genetic predispositions alone do not account for the entirety of substance abuse development (Li & Burmeister, 2010). Socio-economic status, peer pressure, gender, and cultural background also influence substance abuse regardless of the individual’s genetic predispositions (Li & Burmeister, 2010). Therefore, not all cases of homelessness caused by substance abuse are determined by biological factors, but genetic factors can increase the risk for substance abuse.
Aging is also a biological factor that can predispose individuals to homelessness because of the relationship between biology and culture. As biological potential weakens with aging, the cultural support should increase to compensate for that loss (Thompson & Bridier, 2013). Individuals whose cultural support does not increase may have difficulty in maintaining employment in later stages of life and will be at risk for poverty and losing their home.
Two cases reported by Thompson and Bridier (2013) illustrate how aging can predispose individuals to homelessness if they do not compensate for the loss of physical strength with cultural support. One participant in the research was a welder and landscaper, but with the onset of multiple physical ailments in older age, the participant was no longer able to work without any other vocational training. The other participant was an individual who lost his job after the company he had been working for closed, and because of a recent surgery, that person was no longer able to perform physical work and find a job. Both individuals lost their biological potential with aging, but they failed to develop an adequate social support network and did not receive any community support, so their aging process resulted in unemployment and homelessness.
Social Factors of Being Homeless
A lot of homeless people have experienced childhood abuse, which is considered a significant risk factor for homelessness. According to Herman, Susser, Struening, and Link, (1997), childhood neglect combined with any type of abuse is the most significant risk factor for homelessness, followed by single forms of abuse. A 1994 nationwide survey on adult homelessness found that people who have experienced lack of care (66%), physical abuse (47.8%), sexual abuse (14.7%), combined neglect and abuse (53.9%), and any other form of childhood adversity (68.5%) found themselves homeless at some point in their lives (as cited in Herman et al., 1997).
Various explanations are offered to clarify why family dysfunction and childhood abuse can contribute to the development of homelessness. One possible explanation is the predisposition to various mental illnesses associated with childhood abuse (Koegel, Melamid, & Burnam, 1995). The meta-analysis by Fazel, Khosla, Doll, and Geddes (2008) pooled data from 29 studies and found that the most common mental illnesses in homeless people were psychotic disorders (12.7%), major depression disorder (11.4%), and personality disorders (23.1%). Homeless people with severe psychological disorders lose their social support because they do not see the necessity for voluntary treatment and refuse to take psychotropic medication (Belcher, 1989). Without community support and severe symptoms associated with their disorders, they cannot take care of themselves and end up homeless.
Childhood abuse is also considered a significant risk factor for developing substance dependence, which is one of the leading causes of homelessness in single adults (Koegel et al., 1995; Herman et al., 1997). Substance dependence appears to be the most significant disorder among homeless people with the prevalence of 37.9% for alcohol dependence and 24.4% for drug dependence (Fazel et al., 2008). Substance dependency is estimated to be one of the leading causes homelessness in 68% of the cities in the US (US Conference of Mayors, 2008), and childhood abuse increases the risk for homelessness by increasing the risk for substance abuse and dependency.
Peer pressure is another significant factor that can determine substance dependency among adolescents (Li & Burmeister, 2010), and eventually lead to homelessness. The path to homelessness through peer pressure is indirect because peer pressure causes a chain of events that eventually create the other outcomes that result in homelessness. For example, an individual can engage in substance abuse because of peer pressure. Once the individual develops substance dependency, that person will more likely experience a decline in academic achievement (Aertgeerts & Buntinx, 2002), which leads to lower employment chances and poor socioeconomic outcomes.
Even if the affected individual is successfully treated with psychosocial or behavioral interventions, up to 70% of alcohol and drug users experience a relapse within a year after treatment (Heilig, Egli, Crabb & Becker, 2010). During adulthood, various environmental triggers can cause the relapse, but the most common ones are unemployment and being single (Blazer & Wu, 2009). Therefore, substance dependency that starts with peer pressure can cause a lifelong risk for relapse and homelessness once social support decreases and functioning becomes impaired.
For considering the issue of homelessness, it is not possible to isolate the causal factors because multiple factors determine the decision-making of individuals and their outcomes in life. While there is strong evidence that genetic differences can account for substance abuse, which is one of the leading causes of homelessness in single adults, genes are not the only variable that determines substance abuse because social influences (e.g. childhood abuse and peer pressure) determine it as well. While childhood abuse can increase the individual’s predisposition to mental illnesses, genetic factors can determine whether the individual will develop those disorders while contextual factors (e.g. lack of affordable housing and social support) can determine whether they become homeless. Therefore, the biological, social, contextual, and psychological factors can all determine the pathways to mental disorders or substance abuse, which can then result in homelessness if the individual lacks individual or social resources to deal with those problems.
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Yoo, B. K., Shim, J. C., Lee, B. D., Kim, C., Chung, Y. I., Park, J. M., Kwon, D. H. (2012). Association of the neuronal cell adhesion molecule (NrCAM) gene variants with personality traits and addictive symptoms in methamphetamine use disorder. Psychiatry Investigation, 9(4), n. pag. doi:10.4306/pi.2012.9.4.400