Elsevier

Schizophrenia Research

Volume 51, Issues 2–3, 1 September 2001, Pages 171-180
Schizophrenia Research

Quality of life in schizophrenia: contributions of anxiety and depression

https://doi.org/10.1016/S0920-9964(99)00151-6Get rights and content

Abstract

A number of studies have demonstrated a strong relationship between quality of life in schizophrenia and general psychopathology measures, and moreover, that the positive, negative, and disorganized symptoms are less related to quality of life. The current investigation examined the relationship between quality of life and symptomatology in 63 stabilized outpatients diagnosed with schizophrenia or schizoaffective disorder. Consistent with other findings, more severe depression, as rated on the Brief Psychiatric Rating Scale (BPRS) was associated with lower general life satisfaction and lower satisfaction with daily living, finances, health, and social life. In addition, higher anxiety ratings on the BPRS were associated with less satisfaction with global quality of life, daily activities, family, health and social relationship, even when controlling for positive symptoms, negative symptoms, or depression. No other symptoms of schizophrenia were as strongly associated with subjective quality of life. Anxiety was also significantly correlated with a number of positive and negative symptoms while depression was substantially less related. These findings, suggest that more precise analyses of general psychopathology, and anxiety in particular, may be necessary to further clarify the factors involved in quality of life in schizophrenia. In addition, these findings suggest future directions for theories of affect and treatment in schizophrenia.

Introduction

Quality of life is a broad construct, including subjective satisfaction in different areas of life, and objective criteria such as social functioning, activities of daily living, and physical health (Lehman, 1988). It has increasingly been viewed as an important indicator of functioning for patients with schizophrenia (Meltzer, 1992, Meltzer, 1999). A number of assessment measures have been developed to assess both subjective and objective components of quality of life (Goodman et al., 1997). However, how overall quality of life and its components are influenced by different symptoms or syndromes within schizophrenia has only recently begun to be addressed (Browne et al., 1996, Dickerson et al., 1997, Galletly et al., 1997, Packer et al., 1997).

Correlational analyses have demonstrated that a number of symptom clusters are related to poor quality of life. In a longitudinal study, Galletly et al. (1997) demonstrated that changes in quality of life were most highly correlated with changes in general psychopathology. These correlations were higher than the correlations between changes in quality of life and changes in negative symptoms or changes on the Positive and Negative Syndrome Scale (PANSS) overall score. Dickerson et al. (1998) found the PANSS depression factor to be most highly correlated with global subjective quality of life, in comparison with a number of other indices including other subscales of the PANSS, neuropsychological measures, and demographic or service utilization variables. Heslegrave et al. (1997) also found a stronger relationship between the general psychopathology scale of the PANSS and subjective quality of life than a number of neuropsychological measures and subjective quality of life. They reported that total PANSS scores and the general psychopathology index were equally correlated with global quality of life.

Packer et al. (1997) evaluated psychopathology in schizophrenia using the Brief Psychiatric Rating Scale (BPRS) and found a high correlation between global quality of life and BPRS total score as well as relationship between subjective quality of life and negative and positive symptom clusters. Objective quality of life measures did not correlate significantly with any neuropsychological or symptom measures. In a secondary analysis, Packer's group (Packer et al., 1997) reported that depression was negatively correlated with global life satisfaction and that anxiety was negatively correlated with health care utilization and requirements.

The above studies imply that overall levels of general psychopathology are more highly associated with subjective quality of life than are core positive and negative symptoms in schizophrenia. General psychopathology contains items that include symptoms of depression and anxiety. The studies reviewed above suggest that anxiety and depression may be more critical than other symptoms of schizophrenia, but few studies to date have examined the relative influence of psychotic, mood, and anxiety symptoms on subjective quality of life.

Studies examining the contribution of mood state to subjective quality of life in schizophrenia have primarily focused on depression (e.g. Atkinson et al., 1997, Corrigan and Buican, 1995, Lehman, 1988). Studies have generally found that depression is related to subjective quality of life. For example, Atkinson et al. (1997) reported that patients diagnosed with major depression reported lower subjective quality of life than patients diagnosed with schizophrenia, while objective measures showed that patients with schizophrenia were functioning at a lower level. The authors concluded that subjective quality of life might be greatly biased in patients with mood disorders. However, this study did not address how the mood influenced the subjective quality of life of patients with schizophrenia. Lehman, (1988) demonstrated that depression and anxiety were both consistently related to quality of life in chronically mentally ill populations, and suggested that ‘concomitant assessment of a respondent's level of psychiatric symptoms, especially depression and anxiety, seems advisable in this population’ (p. 56). Corrigan and Buican demonstrated that depression was related to subjective quality of life of patients with schizophrenia, but that other factors were substantially involved, even when depression was taken into account. They concluded that depression and quality of life are, in fact, separate constructs.

The suggestion that both anxiety and depression may be related to quality of life above and beyond other symptoms of schizophrenia leads to a number of questions. One major question is whether anxiety and depression could be epiphenomena of other symptoms of schizophrenia. There have been a number of studies demonstrating that depression may be related to negative symptoms (e.g. Kulhara et al., 1989, Norman et al., 1998, Sax et al., 1996), and to positive symptoms (e.g. Norman and Malla, 1991). In addition, some data indicate that anxiety may be related to positive symptoms (Norman et al., 1998) and negative symptoms (Siris et al., 1998).

Another important issue is that of the use of anxiety and depression as separate constructs when evaluating subjective quality of life. Anxiety, depression, and subjective experience all have a component of negative affect involved, according to emotion theory (Clark and Watson, 1991). However, while anxiety and depression have an overlapping construct of negative affect, they are also theorized to have their own unique components (i.e. anhedonia for depression and hyperarousal for anxiety) (Brown et al., 1998, Clark and Watson, 1991, Watson et al., 1995). Thus, if one construct (e.g. anxiety) remains significantly related to quality of life after controlling for the other (e.g. depression), then the underlying common affect (i.e. negative affect) would not fully explain this relationship.

The current investigation examined the relationship between multiple symptom domains and quality of life in a cohort of recently stabilized outpatients with schizophrenia. It was predicted that anxiety and depression would each contribute significantly to quality of life indices and that the association between positive, negative, and disorganized symptoms and quality of life would be less significant.

Section snippets

Subjects

Subjects were recruited as part of a longitudinal study examining patterns of recovery and relapse in schizophrenia. The overall goal of the longitudinal study is to examine transition from stabilization to maintenance stages of treatment in this population. Therefore, all subjects were in the post-acute, stabilization phase of treatment. Subjects were recruited upon admission to an outpatient treatment program, with inclusion criteria including: (a) age 18–55; (b) diagnosis of schizophrenia or

Results

The average age of patients was 35.67, ranging from 20 to 55 years old. Thirty-seven (58.7%) of the patients were male and 26 (41.3%) were female. Ethnicity of the sample was 81.0% white, 14.3% African–American, and the remainder identified themselves as ‘other’. Patients were on a variety of antipsychotic medications (36.5% atypical, 24.4% traditional neuroleptic, 19.0% clozapine, and 15.0% combination), and on additional medications as well (28% on benezodiazepines, 29.4% on antidepressants).

Discussion

Consistent with other studies evaluating the relationship between symptoms and subjective quality of life (e.g. Galletly et al., 1997, Lehman, 1988, Packer et al., 1997), depression significantly contributed to a number of indices of subjective quality of life, while positive, negative, and disorganized symptoms made little contribution. Our findings also showed that anxiety was significantly related to a number of dimensions of subjective quality of life in our population of recently

Acknowledgements

This research was supported by National Institute of Mental Health grant MH 01359 to Dr Smith and by funds established in the New York Community Trust by De Witt-Wallace to Dr Smith.

References (28)

  • L.A Clark et al.

    Tripartite model of anxiety and depression: psychometric evidence and taxonomic implications

    J. Abnorm. Psychol.

    (1991)
  • P.W Corrigan et al.

    The construct validity of subjective quality of life for the severe mentally ill

    J. Nerv. Ment. Dis.

    (1995)
  • F.B Dickerson et al.

    Subjective quality of life in out-patients with schizphrenia: clinical and utilization correlates

    Acta Psychiatr. Scand.

    (1998)
  • R.J Heslegrave et al.

    The influence of neurocognitive deficits and symptoms on quality of life in schizophrenia

    J. Psychiatr. Neurosci.

    (1997)
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