Predictors of the accuracy of self assessment of everyday functioning in people with schizophrenia

Abstract

Despite multiple lines of evidence suggesting that people with schizophrenia have substantial problems in self-reporting everyday functioning and cognitive performance, self-report methods are still widely used to assess functioning. This study attempted to identify predictors of accuracy in self report, both in terms of accurate self-assessment and over-estimation of current functioning. As part of the larger Validating Assessments of Everyday Real-World Outcomes (VALERO) study, 195 patients with schizophrenia were asked to self report their everyday functioning with the Specific Levels of Functioning (SLOF) scale, which includes subscales assessing social functioning, everyday activities, and vocational functioning. They were also assessed with measures of neuropsychological (NP) performance and functional capacity (FC), and were assessed for psychiatric symptomatology. In addition, a friend, relative or clinician informant was interviewed with the SLOF, and an interviewer with access to all information provided by the patient and informant (exclusive of performance-based data) generated "best estimate" ratings of actual, everyday functioning. Patients significantly (p<.001) overestimated their vocational functioning and everyday activities compared to the interviewer judgments. Lower levels of NP and FC performance and everyday functioning on the part of patients were consistently associated with overestimation of their functioning. Patient self-reports were not correlated with any performance-based measures, while interviewer judgments were significantly correlated with patients' performance on NP and FC measures (p<.005). In regression analyses, adjusting for interviewer ratings of functioning, several predictors of the discrepancy between self and interviewer judgments emerged. Higher levels of depressive symptoms were associated with less overestimation in self-reports (p<.001). Delusions, suspiciousness, grandiosity and poor rapport were all significantly (p<.001) associated with over-estimation of functioning compared to interviewer judgments. Poorer NP and FC performance were also associated with over-estimation of everyday functioning, but these results were not statistically significant in multivariate regression models. Consistent with previous studies in schizophrenia, other neuropsychiatric conditions and non-clinical populations, higher levels of depression were associated with increased accuracy in self-assessment. Similarly, lower scores on performance-based measures and judgments of everyday functioning also predicted over-estimation of functioning. Thus, we identified bi-directional predictors of mis-estimation of everyday functioning, even when poor baseline scores were considered. These data suggest that it may be possible to screen patients for their ability to self-report their functioning, but that performance-based measures of functioning provide a less biased assessment.