Physical and mental health-related quality of life among older people with schizophrenia

https://doi.org/10.1016/j.schres.2008.12.008Get rights and content

Abstract

Objective

Since the time of Kraeplin, schizophrenia has been thought of as a disorder with progressive deterioration in functioning. An important aspect of functioning is both physical and mental health-related quality of life (HRQoL). The objective of this study was to examine the relationship of age to both mental and physical aspects of HRQoL in individuals with schizophrenia as compared to normal comparison subjects (NCs).

Methods

Middle-aged and older community-dwelling patients with schizophrenia (N = 486) were compared to NCs (N = 101). Health related quality of life was measured using the SF-36 Physical Health and Mental Health Component scores. The relationship between age and HRQoL was examined using linear regressions. In addition, we performed exploratory analyses to examine the effects of confounding variables on this relationship, and to examine the effects of age on SF-36 subscales.

Results

Patients with schizophrenia had lower SF-36 Physical and Mental Health Component scores than NCs, and these differences persisted after adjusting for the age difference between the two groups. The relationship between age and mental, but not physical, HRQoL was significantly different between the patients with schizophrenia and the NCs. Specifically, older age was associated with higher mental HRQoL among patients with schizophrenia, but not among the NCs. This difference remained significant after examining multiple potential confounding demographic and clinical variables.

Conclusions

This study found that older age was associated with greater mental health quality of life. Longitudinal studies are warranted to confirm our finding, and to examine potential mechanisms responsible for possible improvement in mental HRQoL with age.

Introduction

Schizophrenia, long considered one of the most serious mental illnesses, results in an annual cost to society exceeding $62 billion (Wu et al., 2005). The functional limitations caused by schizophrenia include impairments in neurocognition (Green, 2006, Savla et al., 2007) working (Lieberman, 2006, Palmer et al., 2002), self-care (Friedman et al., 2002), interpersonal relationships, and daily living skills (Siegel et al., 2006). Although, historically, the expected clinical course of a patient with schizophrenia was thought to be one of functional decline (e.g., Kraeplin's depiction of dementia praecox') (Feighner et al., 1972, Lieberman, 2006, Harvey et al., 1999, Spitzer et al., 1975), data from our group (Heaton et al., 2001, Nayak-Salva et al., 2006, Palmer et al., 2003) and others (Rund, 1998, Kurtz, 2005) have shown that, among non-institutionalized people with schizophrenia, the actual course of the disorder is remarkably stable across the life-span (Heaton et al., 2001, Savla et al., 2007, Palmer et al., 2003, Eyler-Zorrilla et al., 2000). Similarly, psychiatric symptoms tend to be less severe in older compared to younger persons with schizophrenia (Jeste et al., 2003, Huber et al., 1980, Harding et al., 1987).

Although cognition and psychiatric symptoms are important outcomes for patients with schizophrenia, quality of life may be the most meaningful outcome. Health-related quality of life (HRQoL), defined as a patient's self-reported perception of his or her physical, emotional, mental, and functional well-being (Gill and Feinstein, 1994), is a way of measuring the impact that a chronic disease has on a person's life and functioning (Guyatt et al., 1993). Prior studies have reported poor HRQoL in patients with schizophrenia, comparable to that of ambulatory patients with AIDS (Patterson et al., 1996). Factors contributing to poorer quality of life in these patients include depression (Reine et al., 2005) and younger age of onset (Sciolla et al., 2003, Patterson et al., 1997). The SF-36 is the most widely used measure of HRQoL, and has been used across a wide range of disease states (Meijer et al., 2002).

In the general population physical HRQoL declines with age, whereas mental HRQoL is stable (Ware et al., 1994), and chronically institutionalized persons with schizophrenia may be at increased risk of age-related functional decline (a key component of HRQoL) (Harvey et al., 2003). Among community dwelling persons, who make up the vast majority of older patients with schizophrenia, data on the relationship between age and HRQoL has been less clear (Reine et al., 2005).

In this study, we examine the relationship between age and physical and mental HRQoL in a sample of 101 normal comparison subjects (NCs) and 486 older adults with schizophrenia. We hypothesized that patients would have worse physical and mental HRQoL than NCs, and that within both groups, older age would be associated with worse physical and mental HRQoL. In addition, we planned to perform two sets of exploratory analyses. First, we explored the relationship between age and SF-36 subscales, to better understand which aspects of HRQoL were most highly correlated with age. In addition, we examined whether demographic and clinical factors that have been previously related to HRQoL (Patterson et al., 1997, Sciolla et al., 2003, Reine et al., 2005) confounded the relationship between age and SF-36 scores.

Section snippets

Study sample

Patients were enrolled as part of clinical research at the University of California San Diego's Advanced Center for Innovation in Services and Intervention Research (ACISIR) between February 1994 and September 2006. The patients with schizophrenia were recruited from outpatient clinics of the San Diego County Adult Mental Health Services, UCSD Healthcare System, board-and-care homes, and the VA. None of the patients met the criteria for remission (Auslander and Jeste, 2004) at the time of study

Demographic characteristics and severity of psychopathology

As shown in Table 1, relative to NCs, patients with schizophrenia were younger, more likely to be male, less likely to be married, and had fewer years of education. The NCs also had a greater number of medical conditions than did the patients with schizophrenia, however after adjusting for the age differences between the two groups, this difference was not significant (F = 1.15, p = .28). As expected, the patients with schizophrenia had greater severity of schizophrenia and depressive symptoms, and

Discussion

The principal findings of this study were: 1. Patients with schizophrenia had lower SF-36 PHC and MHC scores than NCs, and these differences persisted after adjusting for the age and gender difference between the two groups; 2. The relationship between age and mental health-related quality of life (HRQoL) was different between the patients with schizophrenia and the NCs. Specifically, older age was associated with higher mental HRQoL among patients with schizophrenia, but not among the NCs.

Role of funding source

Funding for this study was provided by National Institute of Mental Health grants 067895, 066248, MH64722, by the Department of Veterans Affairs, and by the Veterans Affairs Center for Excellence on Stress and Mental Health (CESAMH). The NIMH and the VA had no further role in study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the paper for publication.

Contributors

David Folsom, Thomas Patterson and Dilip Jeste developed the initial concept for the paper. David Folsom, Colin Depp and Brent Mausbach performed the initial analyses of the data. Ian Fellows, Shahrokh Golshan and Helena Kraemer directed or performed the final analyses. Barton Palmer and Veronica Cardenas provided critical reviews and contributed to the content of the manuscript. All authors contributed to and have approved the final manuscript.

Conflict of interest

Dr. Dilip Jeste has the following conflicts of interest:

  • 1.

    Donation of medication for an NIH-funded grant: AstraZeneca, Bristol–Myers Squibb, Eli Lilly, Janssen

  • 2.

    Unrestricted educational supplement to an NIH-funded research training grant: Janssen

  • 3.

    Honoraria and Consultation: Abbott, Bristol–Myers Squibb, Eli Lilly, Janssen, Solvay-Wyeth, Otsuka

None of the other authors have any conflicts of interest to report.

Acknowledgements

This work was supported, in part, by the National Institute of Mental Health grants 067895, 066248, MH64722, by the Department of Veterans Affairs, and by the Veterans Affairs Center for Excellence on Stress and Mental Health (CESAMH).

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