© 2004 American Public Health Association
Carol S. North is with the Dept of Psychiatry, Washington University School of Medicine, St Louis, Mo. Karin M. Eyrich is with the Dept of Psychiatry and George Warren Brown School of Social Work, Washington University School of Medicine. David E. Pollio is with the George Warren Brown School of Social Work, Washington University School of Medicine. Edward L. Spitznagel is with the Dept of Mathematics and Biostatistics, Washington University. Correspondence: Requests for reprints should be sent to Carol S. North, MD, MPE, Washington University School of Medicine, Dept of Psychiatry, 660 South Euclid Ave, St Louis, MO 63110 (e-mail: northc{at}psychiatry.wustl.edu).
Objectives. We examined the prevalence of psychiatric illness among 3 homeless populations in St. Louis, Mo, in approximately 1980, 1990, and 2000. The 3 studies were conducted with the same systemic research methodology. Methods. We compared selected demographics and lifetime substance abuse and dependence and other mental illness among the 3 populations. Results. Among the homeless populations we studied, the prevalence of mood and substance use disorders dramatically increased, and the number of minorities within these populations has increased. Conclusions. The prevalence of psychiatric illness, including substance abuse and dependence, is not static in the homeless population. Service systems need to be aware of potential prevalence changes and the impact of these changes on service needs.
Addressing the public health concerns of the homeless population is a major challenge for service providers and policymakers. This population suffers from multiple risk factors, including disproportionately high rates of mental illness and substance use and abuse. Understanding the risk factors and their changing roles is essential for the development of effective policies and programs that address these concerns. Comparing homeless populations across studies and over time has been impeded by methodological difficulties,1,2 including inconsistent definitions of homelessness, varied sampling strategies and locations, and disparate measurement instruments. Differences in population prevalence estimates of homelessness vary by tens of millions because of sampling: low estimates are generated from samples of current homeless-shelter users only (current prevalence, literal homelessness),3 and high estimates are generated from samples of individuals with any lifetime episode of unstable housing (lifetime prevalence, marginal housing).4 This situation complicates efforts to weigh risk factors for homelessness, such as mental illness or substance abuse, across populations and over time. Despite controls for sampling variation, only questionable reliability has emerged in comparisons of standardized and clinician-based estimates of risk.5 Reasonably reliable cross-sectional prevalence estimates and risk factors have emerged from adequately designed population studies over the last decade,2,616 but the effects of time have not been adequately tested in these studies. The homeless population is always described at a discrete time point, which conceptualizes homelessness as a static phenomenon. Changes in the demographics of the homeless population over time may have critical implications for service and public health policy implementation. Housing and labor markets,1721 erosion of public benefits,21 and deinstitutionalization19,21,22 all have been identified as risk factors for homelessness. Changes in these forces over time may shape the evolving complexion of the homeless population and may contribute to the level of mental illness or substance abuse within it. A substantial body of research has shown that economics and federal and state policies powerfully affect risks for homelessness.23 Longitudinal data on the homeless population are generally unavailable. Therefore, the evolving dynamics of this populations demographics are most readily examined by comparing available data from different time periods. Although longitudinal studies represent the gold standard for examining changes in prevalence of risk factors in the homeless population, separate studies that employ similar sampling methods and instrumentation conducted at different times offer an alternative approach. This rationale forms the basis of our study, which capitalizes on population data from 3 studies conducted in St Louis, Mo, at 3 different time points approximately a decade apart. These 3 studies utilized the same methodology with systematic sampling and structured psychiatric interviews, which yielded full psychiatric diagnoses that met American Psychiatric Association (APA) criteria. The purpose of our study is to compare selected demographics and relative prevalence of lifetime psychiatric and substance abuse and dependence diagnoses among 3 homeless populations that were systematically assessed by structured interviews in approximately 1980, 1990, and 2000.
Sampling Two of the data sets for our analyses are products of homeless-population studies conducted a decade apart in St Louis. The first of the 2 data sets was collected between April 1989 and September 1991 as part of an epidemiological study (referred to as the 1990 study in this report). A more recent data set includes 396 index interviews conducted between October 1999 and May 2001 as part of a longitudinal study of service utilization and substance abuse in the homeless population (referred to as the 2000 study in this report). Both studies, conducted in the same parts of the city of St Louis by the same research team, used the same sampling process, with the exception of sampling differences regarding gender. The 1990 data set consists of 2 samples recruited separately by gender with a preplanned ratio of 600 men to 300 women. The 2000 study recruited men and women randomly to reflect their numbers among shelter users and homeless people from public areas in the greater pool of the available population. Statistical sampling methods were used to select these men and women. The 2 studies recruited participants randomly from all overnight and daytime shelters located in the city of St Louis that serve the homeless in numbers proportionate to the size of each shelters roster, as well as from locations on systematically searched streets and other public areas where homeless people are known to congregate. In both studies, individuals were considered homeless if they had no stable residence and were living in a public shelter or in an unsheltered location without a personal mailing address, such as on the streets, in a car, in an abandoned building, or in a bus station. Individuals who resided in inexpensive hotels for less than 30 days also were included. Marginally housed persons, such as those living with friends or relatives or those living in single-room-occupancy facilities, were not included. Fourteen consecutive days of literal homelessness were required for inclusion in the 2000 study. A third data set included in our comparative analysis consists of data extracted from the St Louis sites first wave of the National Institute of Mental Health (NIMH)sponsored Epidemiologic Catchment Area (ECA) study, which was collected between April 1981 and March 1982 (referred to as the 1980 ECA study in this report). ECA subjects were selected from 2 regions of the St Louis area: the city itself and a section of northeastern St Louis County that borders on the city of St Louis. These regions were selected for their economic similarity to the area from which the homeless data were collected. The excluded region was a 3-county area of suburban communities, small towns, and rural areas in St Charles, Lincoln, and Warren Counties.24 Not included in the ECA subsample were those who were institutionalized, such as in nursing homes, board and care homes or boarding homes, prison or jail, mental retardation facilities, mental hospitals, chronic hospitals, and residential treatment centers. Individuals were considered to have a lifetime history of homelessness if they responded affirmatively to either of 2 questions from the antisocial personality disorder section of the Diagnostic Interview Schedule: (1) "Have you ever traveled around for a month or more without having any arrangements ahead of time and not knowing how long you were going to stay or where you were going to work?" and (2) "Has there ever been a period when you had no regular place to live for at least a month or so?" From the St Louis ECA data set of 828 men and 1395 women, 69 men and 81 women provided an affirmative response to at least 1 of these 2 questions and identified an episode approximating homelessness at some time in their lives. The 1980 ECA study differs from the other 2 studies in its definition of homelessness (lifetime in the 1980 ECA study vs current episode of homelessness in the other 2 studies) and a sample not identified on the basis of current homelessness (although individuals included were subselected for our studys analyses by history of homelessness).
Nearly 7% of the 1980 ECA study sample met our studys working definition of homelessness, and more ECA men (9.8%) than women (5.0%) had been homeless (
Instruments
Data Analysis
Demographics Table 1
Psychiatric Disorders Figures 1
Alcohol use disorder was already highly prevalent among homeless men in 1980, and it increased little over the next 2 decades. Among women, alcohol use disorder was comparatively much less prevalent but was increasing more substantially over the 2 decades of evaluation. The prevalence of drug use disorder increased dramatically among both men and women over the past 2 decades, and among women, the increase was higher than the prevalence of alcohol use disorder. In 2000, 84% of men and 58% of women had an alcohol or other drug use disorder. Also in 2000, substance use disorders accounted for the vast majority of psychopathology (prevalence of any psychiatric disorder was 88% among men and 69% among women). In 1980, the abused drug of choice was cannabis, but it was surpassed over the next 2 decades by cocaine, which had not been found among homeless men or women in 1980. The popularity of amphetamine and sedative-hypnotic abuse decreased after 1980. Opioid abuse remained relatively unchanged over the 2 decades and was the third most prevalent abused drug of choice in 2000. A few changes were evident in ages of onset of disorders. Among men, age of onset of bipolar disorder increased substantially, especially after 1990. The age of onset of bipolar disorder among men increased to near the age of onset of cocaine use disorder, which is consistent with the often comorbid occurrence of bipolar disorder with cocaine use disorder among men (38% of cases in 1990 and 54% in 2000). Major depression also increased among men relative to 1980, whereas age of onset of alcohol and drug use disorders (and specifically cannabis) declined. Among women, age of onset of schizophrenia decreased and age of cocaine use disorder increased relative to 1980.
Trends Over Time These 3 data sets suggest an evolution of the characteristics of the homeless population in St Louis over 2 decades. There are more minorities in the homeless population. Mood and substance use disorders have dramatically increased, especially drug use disorders (predominantly cocaine) among women. Major depression is the main diagnosis in the nonsubstance diagnosis category, and substance use disorders, especially alcohol, represent the vast majority of all disorders. Cocaine abuse was not evident in 1980, when the abused drug of choice was cannabis, but by 1990, it had established itself as the abused drug of choice and retained this distinction in 2000.
Methodological Limitations The 1980 ECA study was a community sample collected for other purposes that happened to contain people with a history of homelessness that we retrospectively approximated. The 1980 and 1990 studies used essentially identical sampling methods, although the 1990 sample had an arbitrary male to female ratio of 2 to 1 that compromised our ability to examine gender differences. The inherent nonuniformity of sampling prohibits the ability to draw strictly straight-line inferences from the data. Because the lifetime (not current) definition of homelessness in the 1980 ECA study called for analysis of lifetime rather than current psychiatric diagnosis, examination of the impact of recent symptoms on current homelessness was not possible. In the other 2 studies, entry into homelessness generally occurred more than 1 year prior to interview, which reduced the relevance of current symptoms to the prevalence focus of the research question. The criteria used for psychiatric diagnoses have evolved somewhat over time (from DSM-III to DSM-III-R to DSM-IV). The higher prevalence of several disorders identified with DSM-IV criteria in the 2000 study is especially noteworthy, because that diagnostic prevalence with DSM-IV has been found to be nearly 20% less than with DSM-III-R.29 Directional causality of relationships between mental illness and homelessness cannot be determined with the data available; therefore, the results cannot directly inform the debate on the degree to which mental illness may lead to homelessness and the degree to which homelessness may precipitate further mental illness. The findings from our study should spur additional research to further address these questions and to inform policy discussions.
Implications for Service Delivery Because of the increase in major depression, mental health services should build upon rather than displace the current attention to services for psychiatric illnesses, such as schizophrenia. Because a portion of the major depression in the homeless population may represent confounding with aspects of the homeless condition (with a demonstrated link between exposure to the elements and the likelihood of this disorder),5 it also is possible that a portion of the increase in bipolar disorder may be confounded with the precipitous increase in cocaine abuse/dependence (on the basis of its frequent overlap among the same individuals) and the increase in age of onset of cocaine abuse/dependence. More research is needed to further explore these possibilities. Shifts in social policies may inadvertently contribute to the changing complexion of the homeless populations demographics with regard to race, substance abuse and dependence, and other mental illness.1921 For populations dealing with substance abuse and dependence, increased risk for homelessness might be an unintended end product of social policies aimed at alleviating poverty. It has been repeatedly argued that US policy on deinstitutionalization has contributed to the overall prevalence of mental illness in the homeless population.3034 Testing causality would require minimally longitudinal methods and a nonhomeless poverty comparison group that are not provided in the data for our report. Further research is needed to determine the degree to which social policy modifies the risk for homelessness through these various factors. In the meantime, policymakers are advised to be vigilant for negative effects of policy change on specific subpopulations.
Future Research Directions
The findings of our study, although inconclusive because of methodological limitations, suggest that prevalence of mental illness and substance abuse and dependence is not static over time in the homeless population. Furthermore, changes are not monolithic, but they particularly apply to certain diagnoses and descriptive characteristics. Service systems need to be cognizant of the potential for prevalence changes and how these changes translate into evolving service needs. Building on these findings, our study speculates that social and economic policies may contribute to differential risks for homelessness among minorities as well as among those with addiction or major depression.
This paper was supported by grant R01DA10713 from the National Institute on Drug Abuse. An earlier version of these results was presented at the 2001 American Public Health Association Annual Meeting in Atlanta, Ga.
Human Participant Protection
Contributors C. S. North and D. E. Pollio designed and received funding for the study, gathered data, directed the data analysis, and collaborated in writing the article. K. M. Eyrich performed data analysis and assisted with writing the article. E. L. Spitznagel assisted with the study design, advised the analysis of the data, and assisted with writing the article. Accepted for publication February 11, 2003.
1. Rossi PH, Wright JD, Fisher GA, et al. The urban homeless: estimating composition and size. Science. 1987;235:13361341.
2. Susser E, Conover S, Struening EL. Problems of epidemiologic method in assessing the type and extent of mental illness among homeless adults. Hosp Comm Psychiatry. 1989;40:261265. 3. US Dept of Housing and Urban Development. A Report to the Secretary on the Homeless and Emergency Shelters. Washington, DC: Office of Policy Development and Research; 1984. 4. Link B, Phelan J, Breshnahan M, et al. Lifetime and 5-year prevalence of homelessness in the United States: new evidence on an old debate. Am J Orthopsychiatry. 1995;65:347354.[Web of Science][Medline] 5. North CS, Pollio DE, Thompson SJ, et al. A comparison of clinical and structured interview diagnoses in a homeless mental health clinic. Community Ment Health J. 1997;33(6):531543.[Web of Science][Medline] 6. Farr RK, Koegel P, Burnam A. A study of homelessness and mental illness in the skid row area of Los Angeles: a report to NIMH. Rockville, Md: National Institute of Mental Health; 1986. 7. Sosin MR, Colson P, Grossman S. Homelessness in Chicago: Poverty and Pathology, Social Institutions and Social Change. Chicago, Ill: University of Chicago Press; 1988.
8. Koegel P, Burnam MA. Alcoholism among homeless adults in the inner city of Los Angeles. Arch Gen Psychiatry. 1988;45:10111018.
9. Koegel P, Burnam MA, Farr RK. The prevalence of specific psychiatric disorders among homeless individuals in the inner city of Los Angeles. Arch Gen Psychiatry. 1988;45:10851092.
10. Breakey WR, Fischer PJ, Kramer M, et al. Health and mental health problems of homeless men and women in Baltimore. JAMA. 1989;262(10):13521357. 11. US Dept of Housing and Urban Development Interagency Council on the Homeless. The 1989 Annual Report of the Interagency Council on the Homeless. Washington, DC: Government Printing Office; 1989. 12. Smith EM, North CS, Spitznagel EL. A systematic study of mental illness, substance abuse, and treatment in 600 homeless men. Ann Clin Psychiatry. 1992;4(2):111120. 13. Padgett D, Struening EL, Andrews H. Factors affecting the use of medical, mental health, alcohol, and drug treatment services by homeless adults. Med Care. 1990;28(9):805821.[Web of Science][Medline]
14. Robertson MJ, Zlotnick C, Westerfelt A. Drug use disorders and treatment contact among homeless adults in Alameda County, California. Am J Public Health. 1997;87:221228. 15. Sosin MR, Bruni M. Homelessness and vulnerability among adults with and without alcohol problems. Subst Use Misuse. 1997;32:939968.[Web of Science][Medline]
16. Susser E, Betne P, Valencia E, et al. Injection drug use among homeless adults with severe mental illness. Am J Public Health. 1997;87:854856. 17. Rossi PH, Wright JD. The determinants of homelessness. Health Aff. 1987;6:1932.[Medline] 18. McChesney KY. Family homelessness: a systemic problem. J Soc Issues. 1990;46:191205.[Web of Science] 19. Jencks C. The Homeless. Cambridge, Mass: Harvard University Press; 1994. 20. OFlaherty B. Making Room: The Economics of Homelessness. Cambridge, Mass: Harvard University Press; 1996. 21. Blau J. The Visible Poor: Homelessness in the United States. New York, NY: Oxford University Press; 1992. 22. Mechanic D. Evolution of mental health services and areas for change. New Dir Ment Health Serv. 1987;36:313. 23. Aviram U. Community care of the mentally ill: continuing problems and current issues. Community Ment Health J. 1990;26:6988.[Web of Science][Medline] 24. Diagnostic and Statistical Manual of Mental Disorders, Third Edition. Washington, DC: American Psychiatric Association; 1980. 25. Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition. Washington, DC: American Psychiatric Association; 1987. 26. Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. Washington, DC; American Psychiatric Association; 1994. 27. Leaf P, Myers JK, McEvoy LT. Procedures used in the Epidemiologic Catchment Area Study. In: Robins LN, Regier DA, ed. Psychiatric Disorders in America: The Epidemiologic Catchment Area Study. New York, NY: The Free Press; 1991:1132.
28. Narrow WE, Rae DS, Robins LN, et al. Revised prevalence estimates of mental disorders in the United States: using a clinical significance criterion to reconcile 2 surveys estimates. Arch Gen Psychiatry. 2002;59:115123. 29. Bassuk EL, Lamb HR. Homelessness and the implementation of deinstitutionalization. New Dir Ment Health Serv. 1986;30:714. 30. Belcher JR. Relationship between the deinstitutionalization model, psychiatric disability, and homelessness. Health Soc Wk. 1988;13:145153. 31. Durham ML. The impact of deinstitutionalization on the current treatment of the mentally ill. Int J Law Psychiatry. 1989;12:117131.[Web of Science][Medline] 32. Belcher JR. Moving into homelessness after psychiatric hospitalization. J Soc Serv Res. 1991;14:6377.
33. Bachrach LL. What we know about homelessness among mentally ill persons: an analytical review and commentary. Hosp Comm Psychiatry. 1992;43:453464. 34. Goldman HH. Deinstitutionalization and community care. Harvard Rev Psychiatry. 1998;6:219222.[Web of Science][Medline] This article has been cited by other articles:
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||