Elsevier

Schizophrenia Research

Volume 63, Issues 1–2, 1 September 2003, Pages 79-88
Schizophrenia Research

Apathy in schizophrenia: clinical correlates and association with functional outcome

https://doi.org/10.1016/S0920-9964(02)00433-4Get rights and content

Abstract

Apathy is considered one of the negative symptoms of schizophrenia, but its natural history and relationship to other clinical characteristics have not been systematically studied. The purpose of this cross-sectional study was to measure the level of apathy in schizophrenia and its relation to other symptoms and functional outcome. Twenty-eight patients with schizophrenia, and receiving antipsychotic treatment, were assessed with the Apathy Evaluation Scale (AES). The mean level of apathy of patients with schizophrenia, as rated by the AES, was significantly higher than that of matched healthy control subjects. In the patients, apathy was not significantly correlated with positive symptoms or depressive symptoms. It was significantly correlated with the item “emotional withdrawal” on the negative subscale of the Positive and Negative Syndrome Scale (PANSS), but was not correlated with the overall negative subscale score. Apathy was more highly associated with functional outcome than were other symptom measures, and it was independently associated with functional outcome above and beyond other negative symptoms. It was not associated with observed interest in playing a video game or performance on a simulated clerical task.

Introduction

Apathy has been defined as a “lack of motivation that is not attributable to diminished level of consciousness, cognitive impairment, or emotional distress” Marin, 1990, Marin, 1991. It is manifested clinically by diminishment in goal-directed behaviour, goal-directed cognition, and affective responsivity to events. Signs and symptoms of apathy have long been recognized as common in schizophrenia. Bleuler (1911) described it as “an indifference to everything—to friends and relations, to vocation or enjoyment, to duties or rights, to good fortune or to bad.” Similarly, his contemporary Kraepelin (1919) commented that his “patients have lost every independent inclination for work and action; they sit about idle, trouble themselves about nothing, do not go to their work, neglect their most pressing obligations, although they are perhaps still capable of employing themselves in a reasonable way if stimulated from outside.”

Despite these historical accounts, there has been little quantitative study of the level of apathy in schizophrenia and its relationship to other clinical characteristics. This is reflected in, and perpetuated by, the lack of specific rating scales or subscales pertaining to apathy in the schizophrenia literature. Although apathy is included in some rating scales as one of several negative symptoms associated with schizophrenia Andreasen, 1982, McGlashan and Fenton, 1992, the number of items measuring this construct is few, limiting the ability of existing measures to specifically measure apathy. In addition, the scales are not designed to yield an overall score reflecting apathy specifically, since the items measuring it are sometimes found across different subscales, or are commingled on the same subscale with items reflecting other constructs. For example, the Scale for Assessment of Negative Symptoms (SANS) (Andreasen, 1982) includes a subscale on “avolition/apathy,” with four items representing grooming and hygiene, impersistence at work or school, physical anergia, and a global rating. However, items on recreational interests and relationships with friends, which also could reflect apathy, are found on the “anhedonia/asociality” subscale. On the Positive and Negative Syndrome Scale (PANSS) (Kay et al., 1987), two out of seven items on the negative subscale appear to measure apathy—“emotional withdrawal” from life events, and “passive-apathetic social withdrawal.” The Brief Psychiatric Rating Scale (BPRS) (Overall and Gorham, 1962) has only one item which arguably relates to apathy—“emotional withdrawal,” defined as “deficiency relating to the interviewer and… interview.”

In contrast, studies in other disorders have shown that the construct of apathy can be measured specifically and in a reliable and valid manner. Marin et al. (1991) developed the Apathy Evaluation Scale (AES), which contains 18 items that address behavioral, cognitive, and emotional aspects of apathy as a psychological dimension. They showed that clinician, informant, and self-rated versions of the scale were reliable and valid in patients with major depression, Alzheimer's Disease, and stroke. They performed a factor analysis and found that the AES was predominantly a single-factor scale. They confirmed that multiple forms of reliability (internal consistency, test-retest and interrater) were satisfactory. They presented evidence of several types of validity, including: the ability of the AES to discriminate between diagnostic groups according to mean levels of apathy, the discriminability of apathy ratings from standard measures of depression and anxiety, convergent validity between the three versions of the scale, and criterion-related validity derived from observing subjects playing with games (Marin et al., 1991). Other studies, using the AES or the Neuropsychiatric Inventory (NPI), which has an apathy subscale, have supported the notion that apathy is discriminable from depression, by finding that a substantial fraction of patients with Parkinson's Disease, Alzheimer's Disease, frontotemporal dementia, Huntington's Disease, or progressive supranuclear palsy have apathy in the absence of depression Starkstein et al., 1992, Starkstein et al., 2001, Levy et al., 1998. The presence and degree of correlation between apathy and depression, and their relative prevalence, have also been found to differ depending on diagnosis Marin et al., 1991, Marin et al., 1994, Starkstein et al., 1992, Starkstein et al., 2001, Levy et al., 1998, providing further evidence that they are discriminable.

In contrast, instruments specifically designed to measure apathy have yet to be used in schizophrenia research, where there is a lack of studies designed to assess the relationship of apathy to functional status and other clinical characteristics. The purpose of the present research was to study apathy using the AES in a group of patients with schizophrenia. Several more specific aims of this study are outlined below.

First, since apathy has been identified as a frequent manifestation of schizophrenia, we aimed to measure the mean level of apathy in patients with schizophrenia, and hypothesized that this would be significantly higher than in healthy control subjects.

Second, we aimed to examine whether apathy is discriminable from other symptom dimensions. In previous studies, rating scale items that reflect apathy were found to be correlated with other negative symptoms such as restricted affect and poverty of thought and speech, but were found to have little or no correlation with positive symptoms Andreasen, 1982, Bilder et al., 1985, Fenton and McGlashan, 1991, McGlashan and Fenton, 1992. As for the relationship between apathy and depression, this has not been specifically examined in schizophrenia. We hypothesized that, in patients with schizophrenia, apathy as measured by the AES would be correlated with other negative symptoms and with depressive symptoms, but that it would be discriminable from these dimensions, and that the correlations would thus be modest. We expected, however, that apathy would correlate highly with the PANSS items “emotional withdrawal” and “passive-apathetic social withdrawal,” since these items appear to reflect the diminished affective responsivity and goal-directed behaviour that are a part of apathy. We also hypothesized that apathy would be independent from, and thus not correlated, with positive symptoms.

A third aim of the study was to determine the strength of the association between apathy and functional outcome. Negative symptoms, more so than positive symptoms, have been found to be strongly predictive of subsequent functional impairment in schizophrenia Fenton and McGlashan, 1991, Hwu et al., 1995, Ho et al., 1998, Moller et al., 2000. Fenton and McGlashan (1991) found that the SANS subscales “avolition” and “anhedonia”, i.e. those which appear to correspond most closely to apathy, were the most predictive of long-term functional outcome among the subscales on the SANS or Scale of Assessment of Positive Symptoms (SAPS). We hypothesized that, cross-sectionally, apathy would correlate negatively with functional outcome more strongly than negative symptoms or positive symptoms, and that it would be correlated with functional outcome independent of other negative symptoms or positive symptoms. We also hypothesized that measured apathy would demonstrate criterion-related validity by correlating with patients' behaviour on two real-world indicators of motivation—the amount of time spent playing a computer game, and performance on a simulated office task. We chose these assessments because they provided a directly observed measure, rather than a subjective report, of patients' level of motivation to freely initiate or maintain leisure/work activity.

Section snippets

Subjects

Twenty-eight patients were recruited at the Centre for Addiction and Mental Health (CAMH) in Toronto. At the time of assessment, two were inpatients and 26 were outpatients. Twenty-five fulfilled DSM-IV criteria for schizophrenia and three for schizoaffective disorder, as determined by the Mini International Neuropsychiatric Interview (MINI) (Sheehan et al., 1998). Twenty-eight healthy control subjects were recruited from the surrounding community and were matched to the patients on the basis

Results

Demographic characteristics of the patient and control groups are shown in Table 1. T-tests revealed no significant differences in mean age and parental SES between the groups. Chi-squared tests of association showed no significant differences between the groups in sex ratio or the proportion of subjects with English as their mother tongue. Clinical characteristics of the patient sample are shown in Table 2. Patients' mean antipsychotic dosage in daily chlorpromazine equivalents

Discussion

Our first main aim in this study was to measure the level of apathy in patients with schizophrenia. We hypothesized that it would be significantly elevated compared to normal. Our patient sample indeed showed elevated apathy compared to normal controls, as measured by the AES. The effect size of this difference (d=1.35 for AES-S and 1.61 for AES-C) was large, according to Cohen's effect size convention (Cohen, 1992). The degree of elevation in apathy, as rated by the AES-C, was comparable to

Acknowledgements

We thank Penny Harris, Corey Jones, Alice Kusznir, Ed McAnanama, and Sandy Richards for their assistance.

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