The Mental and Physical Health of the Homeless

Evidence From the National Survey on Psychiatric and Somatic Health of Homeless Individuals (the NAPSHI Study)

Background: The health status of homeless individuals in Germany has been described incompletely. Mental and somatic illnesses seem to contribute to the high mortality in this cohort.

Methods: In this national, multicenter, cross-sectional study, data were collected on the health of 651 homeless individuals in the metropolitan regions of Hamburg, Frankfurt, Leipzig, and Munich metropolitan regions. The lifetime prevalences of physician-diagnosed mental and somatic illnesses were determined with interview-based questionnaires. Furthermore, clinical and laboratory examinations were carried out. Multivariable regressions were performed to identify determinants of health status and access to care.

Results: High prevalences of both mental and somatic illnesses were confirmed. Particularly, cardiovascular and metabolic diseases were highly prevalent. Evidence for possible unrecognized arterial hypertension and possible unrecognized hypercholesterolemia was found in 27.5% and 15.6% of homeless individuals, respectively. 23.1% of study participants reported having received a diagnosis of a mental illness. Evidence for a possible unrecognized mental illness was found in 69.7%. A history of immigration from another country to Germany was found to be an important determinant of the summed scores for mental, somatic, and possible unrecognized illness. Homeless individuals of non-German origin were more likely to be living without shelter (p = 0.03) and to lack health insurance (p < 0.001).

Conclusion: High prevalence rates for mental and somatic illnesses and limited access to mainstream medical care were found. Homeless individuals appear to receive inadequate care for mental illness. Healthcare programs for homeless individuals in Germany should pay particular attention to homeless migrants.

An estimated 417 000 homeless persons were living in Germany in 2020 (1). Their health and healthcare situation has been described incompletely. In particular, representative data are lacking on the prevalence of mental and somatic illnesses. Compared with the general population, standardized mortality rates in homeless people are higher by a factor of two to five, depending on the study (2). Common causes of death that have been described are infectious diseases and suicides, injuries, and poisoning (3). In parallel, the presence of mental illnesses—especially misuse or dependence from alcohol, tobacco, and illegal substances—has been identified as a risk factor for premature death in homeless persons (4). Precarious living conditions and the exposure to noxious substances are associated with an increased risk for diverse somatic illnesses (5). With increasing age of homeless people chronic, non-infectious disorders also gain relevance. A recently published narrative review underlines the increased prevalence of cardiovascular disorders, musculoskeletal disorders, and disorders of the respiratory system compared with the general population in Germany (6).

Earlier studies identified the origin of homeless people as an important determinant of health (7, 8). In the literature, a positive as well as a negative association of migration history with health is the subject of discussion (9). In the coming years, an increase in the number of homeless people of non-German origin is expected (10). This underlines the need for stratification of health data according to the individual migration history (11).

Access to medical care is crucial for securing the health of a population in the long term (12). But individual and structural factors make treating homeless people in the regular medical systems difficult. Healthcare is therefore often provided by public or charitable support services that enable easy-access help (13).

Differentiated analyses of the health of and care provision for homeless people can be used by political organizations and care providers in order to create target-group specific support services. The present national cross-sectional study investigated the mental and somatic health and the healthcare provision/situation of 651 homeless persons in Germany with special consideration of their migration history.

Methods

The eMethods section provides a detailed explanation of our methods.

Sample

The National Survey on Psychiatric and Somatic Health of Homeless Individuals (NAPSHI) was carried out between June and September 2021 (ethics approval: PV7333). In total, 651 person in Hamburg, Frankfurt, Wiesbaden, Leipzig, Halle, Munich, and Augsburg were included in the study.

Physical health

Self-reported lifetime prevalence rates of physician-diagnosed somatic illnesses were determined by administering an interview-guided questionnaire. To this end, 12 diagnostic groups were interrogated in a dichotomized form. By adding the affirmative responses, sum scores of somatic illnesses were calculated. The point prevalence of somatic illnesses was determined on the basis of clinical and laboratory based surrogate values.

Mental health

The self-reported lifetime prevalence rates of mental illnesses were determined on the basis of an interview-guided questionnaire. The possible presence of depression was queried on the basis of the Patient Health Questionnaire (PHQ)-9 (14). Data on possible generalized anxiety disorder was collected on the basis of the Generalized Anxiety Disorder (GAD) 2 questionnaire (15). If a study participant reported critical substance consumption several days a week or almost daily, a potential substance-related disorder was assumed. A sum score of the point prevalence rates of the named mental disorders was calculated. Furthermore, the feeling of loneliness was determined on the basis of the California Los Angeles (UCLA) Loneliness Scale Version 3 (16).

Possible unrecognized illnesses

If study participants reported not having received a physician diagnosis (reported lifetime prevalence), although diagnostic indications (measured point prevalence) for the possible presence of a particular illness existed, a potential unrecognized illness was assumed.

Results

A total of 651 homeless persons participated in the study. The median age was 43 years, about 20% of participants were female, and half had been born in Germany. The median duration of homelessness was 18 months. According to the European Typology for Homelessness and Housing Exclusion (ETHOS), a large proportion of the people were living rough. Table 1 shows additional sociodemographic characteristics.

Table 1

Data on the sociodemographic and healthcare situation of homeless people in Germany

Mental and physical health

When asked for the lifetime prevalence, physician diagnoses of cardiovascular disease, liver disease, and chronic pulmonary disease were reported particularly often. Also, high measured point prevalence rates of cardiovascular and metabolic disorders were found among homeless persons (Table 2a). Altogether, indications of possible unrecognized somatic disorders were seen in half of the survey participants (Table 2c).

Table 2a

Lifetime and point prevalence of physical illnesses in homeless persons in Germany

Table 2c

Healthcare services and service use by homeless persons

Among study participants, 23.1% reported a physician-diagnosed mental illness. Validated questionnaires indicated a possible anxiety disorder in 27.% and possible depression in 26.9% of study participants. Possible substance-related disorders indicated by increased consumption of alcohol or illegal substances were identified in 42.3% and 29.4% of participants, respectively (Table 2b). Overall about two thirds of participating homeless persons showed indications of a possible unrecognized mental illness (Table 2c).

Table 2b

Lifetime and point prevalence rates of mental illnesses in homeless persons in Germany

Healthcare services and service use

Two thirds of study participants reported having health insurance. Among the surveyed homeless persons, 72% reported having had outpatient contact with a doctor within the preceding 12 months. In this subgroup, the median number of consultations was 3. Furthermore, 42.4% of the homeless people reported having received inpatient treatment in the preceding year. The median number of hospital stays in this subgroup was 4 and the median duration 6 nights (Table 2c).

Comparison of the health of homeless persons with the German general population

The comparison of self-reported lifetime prevalence rates of physician-diagnosed somatic illnesses showed a lower prevalence of known hypercholesterolemia among homeless persons than in the general population. A significantly increased prevalence of dementia was reported by the surveyed homeless persons than was the case in the general population. The lifetime prevalence of HIV infections was also higher in homeless persons than in the general population (eFigure 1a). The lower lifetime prevalence of physician-diagnosed mental illness among homeless persons is in contrast to the increased point prevalence of possible anxiety disorders and depression compared with the general population (eFigure 1c).

eFigure 1a

Comparison of lifetime prevalence rates of mental and somatic illnesses in homeless persons with the general population

eFigure 1b

Comparison of lifetime prevalence rates

eFigure 1c

Comparison of prevalence rates of mental illnesses in homeless persons with the general population

Sociodemographic determinants of health and healthcare services

Our exploration of sociodemographic determinants of health and healthcare showed an association of a high sum score of self-reported physician-diagnosed somatic illnesses with old age, female sex, and living in an institution run by homelessness services (eTable 3). An increased sum score of measured somatic illnesses was also associated with older age, but also with originating from an EU country. The self-reported physician diagnosis of a mental illness was, by contrast, inversely associated with non-German origin, as was a high sum score of possible mental disorders. By contrast, an association was seen for a possible unrecognized illnesses and the non-German origin. Use of medical services was not associated with sociodemographic parameters, but having health insurance was associated with German origin (Table 3).

eTable 1

Sociodemographic characteristics of homeless persons in Germany stratified by origin

Table 3

Selected sociodemographic determinants (aOR [95% CI]) of the health of and services for homeless persons

eTable 3

Sociodemographic determinants (aOR [95% CI]) of health and healthcare services for homeless persons

Origin and migration history

eFigure 2 shows information regarding people’s migration history. Homeless migrants originated primarily from outside the EU (eFigure 2a). Homeless migrants from the EU spend a mean of 66.7% of their time living in Germany without fixed abode, whereas for homeless non-EU migrants this was 22.2% (eFigure 2b). Homeless persons of German origin mentioned as the cause of their continued homelessness often the lack of suitable accommodation and their mental health, whereas homeless EU migrants often cited economic factors as the reason for their continued homelessness (eFigure 2c) and cited these as the reason for migrating (eFigure 2d).

eFigure 2a

Migration history of homeless persons in Germany

eFigure 2b

Migration history of homeless persons in Germany

eFigure 2c

Migration history of homeless persons in Germany

Discussion

This multicenter cross-sectional study investigated 651 homeless persons in Germany. Overall, we found high prevalence rates of mental and somatic illnesses; validated screening instruments suggest underdiagnosis, especially regarding mental illness. Non-German origins were associated with a lower prevalence of mental illness, difficulty accessing healthcare, and the presence of possible unrecognized illnesses.

Physical health

This study confirmed high prevalence rates of somatic illnesses from the metabolic and cardiovascular spectrum. As already found in other studies, infectious diseases, such as HIV/AIDS and tuberculosis, as well as liver and lung diseases are more common in homeless persons than in the general population (6, 17). The results of clinical and laboratory tests show for possible diabetes mellitus, possible chronic lung disease, and HIV infection measured point prevalence rates that are comparable to the reported lifetime prevalence rates. By contrast, cardiovascular disorders and hypercholesterolemia were reported more rarely than observed. In the German general population too, studies have found a difference between the reported diagnoses and examination findings (18). Especially as regards possibly unrecognized arterial hypertension, which affects about 5% of the general population, this study showed a raised prevalence of possible unrecognized arterial hypertension among homeless people of 27.5% (19). The collected data show than especially the lifetime prevalence of disorders associated with substance misuse are more common in homeless persons than in the general population. Laboratory tests showed an indication of chronic liver disease in only 2.3% of homeless people under study. Since the MELD score was validated primarily to estimate the prognosis of advanced cirrhotic liver disease (20), a lower sensitivity overall can be assumed.

Mental health

The critical consumption of alcohol and illegal substances among homeless persons in Germany is similar to the rates in other high-income countries (21). Furthermore, the point prevalence of mental disorders investigated by means of screening instruments is largely consistent with the already published results of a monocenter cross-sectional study from 2020, which also identified high prevalence rates of loneliness, possible anxiety disorders and depression (7, 22).

In contrast to the recent literature, the lifetime prevalence of physician-diagnosed mental disorders among homeless persons is lower than in the German general population (29). It is possible that the described discrepancy is down to the use of more detailed data collection instruments in the comparison study under consideration. Point prevalence rates of depression and generalized anxiety disorder—which measured higher across all age groups than in the general population (23)—also suggest underdiagnosed mental illness in homeless persons, as does the presence of a possible unrecognized mental illness in more than two thirds of study participants.

A systematic study of 166 homeless persons in North America also showed that some 60% of study participants with indications of a mental illness shown in screening instruments had not received a physician diagnosis of a mental illness (24). The direct comparison of mentally ill homeless people with people of the same age and sex who were not homeless but had contact with the police because of mental abnormalities identified among homeless persons a more acute need for help and simultaneously a lower probability of further specialist treatment (25). These data underline the huge need for psychotherapeutic/psychiatric healthcare services for homeless people, which presumably is not adequately met in Germany.

Origin and migration history as determinants of health

We used multivariable linear and logistic models to study the sociodemographic determinants of health and healthcare access. As expected we found an association of old age with a high point prevalence and lifetime prevalence of somatic illnesses. Interestingly, in addition to this, statistically significant associations of the origin of homeless people were identified with different parameters.

The effects of migration history on health is the subject of controversial discussion in the literature. The „healthy migrant effect“ describes better health in migrants than in the native comparator population. This is explained mainly with the fact that especially persons in good health decide to migrate (9). The described phenomenon is seen in the dataset under study with regard to mental health: homeless persons from Germany had significantly higher prevalence rates of mental illness (eTable 2b).

eTable 2b

Point and lifetime prevalence rates of mental illnesses in homeless persons in Germany stratified by origin

As regards the point prevalence of somatic illnesses (eTable 2a) and possible unrecognized illnesses, homeless people with a migration history were affected more commonly, which is possibly directly associated with the healthcare situation in their countries of origin and difficult access to healthcare in Germany. It has been described that legal and linguistic obstacles make it harder to integrate into the social security system and have a negative influence on migrants‘ health (26). Access to regular medical care has been found to be particularly difficult for homeless EU migrants (eTable 2c). This may be due to the fact that mandatory health insurance according to book V of the German Social Code does not apply to economically inactive EU migrants if their residence permit is predicated on their being a member of a health insurance scheme. In addition to nationality, the reason for migration is crucial for integration into statutory emergency support services and social support services (27). More structured support for asylum seeker that was implemented during the refugee wave in the years around 2015 may have contributed to improving the situation of non-EU migrants (28).

eTable 2a

Point and lifetime prevalence rates of somatic illnesses in homeless persons in Germany stratified by origin

eTable 2c

Healthcare services and service use of homeless persons in Germany, stratified by origin

Strengths and limitations of the study

This study is the first multicenter cross-sectional study of the mental and physical health of homeless persons in Germany. Recruiting study participants from a multitude of different support services aimed to reflect the baseline totality of homeless persons in Germany in as representative a fashion as possible. The representiveness of the included cohort is difficult to assess as response rates have not been systematically evaluated. Furthermore, the dataset may be biased as a result of not being able to reach homeless persons. The lifetime prevalence of mental and somatic illnesses was determined via the question of whether an illness had ever been physician-diagnosed. Although this is a commonly used method, underdiagnosis in the cohort can lead to falsely low assumptions. Furthermore, responses given in the sense of social desirability and recall bias may affect the dataset. For this reason, we additionally collected surrogates for possible mental and somatic illnesses. These are subject to relevant limitations as they mostly do not meet the diagnostic gold standard and therefore do not allow definitive diagnoses. The data should therefore be interpreted with caution. The statistical analysis was based on the size of the total dataset after forming sum scores for mental and somatic illnesses. Even though this is an established method, the sum scores we used were not individually validated and do not consider the severity of an individual disorder. Studying persons from different national background can be made difficult by linguistic hurdles. For this reason the questionnaires were translated by native speakers into other languages and the data collection was accompanied by interpreters. The comparison of lifetime prevalence rates of mental and somatic illnesses with the German general population was not successful in each case because of the limited availability of suitable datasets of the German general population. In those cases we took recourse to datasets with lifetime prevalence rates by sex or datasets with (25) year prevalence rates.

In summary, our study confirms high prevalence rates of mental and somatic illnesses in homeless persons in Germany. Deficiencies in healthcare provision can be assumed especially as regards mental illnesses. Homeless people with a history of migration, especially homeless EU migrants, seem disadvantaged as regards their integration into social security systems.

Acknowledgment
We thank the staff of the healthcare institutions and the participating scientists for their support. Special thanks go to Dr Maria Goetzens and Ms Carmen Speck from the German National Working Group on Homeless Assistance Services (BAWO, BAG Wohnungslosenhilfe e. V.) and Professor Ibrahim Kanalan, professor for public law and international economic law at the Law Faculty of Wuerzburg University, for the technical exchange relating to this study.

Funding
The study was funded by the Volkswagen Foundation (AZ 99269). The German Red Cross district association Hamburg Altona and Mitte e.V. Germany, provided the use of a vehicle at no cost during the entire data collection period.

Conflict of interest statement
Prof Ondruschka is a board member of the German Society of Forensic Medicine.

The remaining authors declare that no conflict of interest exists.

Manuscript received on 10 April 2022, revised version accepted on 10 October 2022.

Translated from the original German by Birte Twisselmann, PhD.

Corresponding author
Franziska Bertram
Institut für Rechtsmedizin
Universitätsklinikum Hamburg-Eppendorf
Butenfeld 34, 22529 Hamburg, Germany

Cite this as:
Bertram F, Hajek A, Dost K, Graf W, Brennecke A, Kowalski V, van Rüth V, König HH, Wulff B, Ondruschka B, Püschel K, Heinrich F: The mental and physical health of the homeless—evidence from the National Survey on Psychiatric and Somatic Health of Homeless Individuals (the NAPSHI study). Dtsch Arztebl Int 2022; 119: 861–8. DOI: 10.3238/arztebl.m2022.0357

►Supplementary material

eReferences, eMethods, eTables, eFigures:
www.aerzteblatt-international.de/m2022.0357

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