UC San Diego

The number of older patients with schizophrenia and their demand on the healthcare system are growing. Treatment of the disorder is expanding from symptom reduction to improvement of everyday functioning, but functioning is a complex construct and little is known about the validity of its assessment methods in middle-aged and older patients with schizophrenia. Performance-based measures test the ability to demonstrate functional skills such as financial management and shopping in a laboratory setting and have been proposed as an alternative to self-reports, which may be more susceptible to confounds such as cognitive impairment, depression, or poor insight. The purpose of this study was to evaluate the relationship between these measures and determine how well they correspond to indicators of "real-world" functioning in a group of 77 middle-aged and older outpatients with chronic schizophrenia. Symptoms were assessed with the Positive and Negative Syndrome Scale (PANSS) and Hamilton Rating Scale for Depression. A composite neuropsychological (NP) ability score was calculated from a group of tests that measured executive functioning, verbal memory, processing speed, and attention. Insight was measured with the Birchwood Insight Scale and self-reported and performance- based functioning were measured with the Independent Living Skills Survey (ILSS) and UCSD Performance-Based Skills Assessment (UPSA), respectively. An index score consisting of living situation, driving status, employment, and marital status was created as a measure of "real- world" functional outcome. Path analyses revealed that NP ability significantly predicted both self-reported (beta = .35, p < .05) and performance-based (beta = .60, p < .01) functioning and indirectly predicted real-world functional outcome through its effect on performance-based functioning. The self-report and performance-based measures were weakly correlated (r = .08, ns). The relationship between self-reported functioning and real- world outcome was weak (r = .06, ns) and not confounded by NP ability, depression, or insight. The results suggest that performance-based functioning is strongly determined by NP ability and that it is a better predictor of functional outcome than self-reported functioning in middle-aged and older patients with schizophrenia. Additional research is needed to clarify the construct of functioning and to develop more valid measures for it in this population