Response to Serper and Harvey

Abstract

Serper and Harvey discuss experimental and neuropsychological research on schizophrenia and suggest their integration. They propose that such integration would offer practical and theoretical advantages. Shortcomings of these approaches and of their integration are discussed, within a broader consideration of methodological and conceptual issues in schizophrenia research. The application of experimental methods to study the relationships between brain function and behavior is suggested to be a more productive approach to the study of psychological phenomena in schizophrenia.

The neuropsychological study of schizophrenia: A methodological perspective.

“…Knight and Silverstein (2001) proposed that a strong theoretical model conjoined with experiments that manipulate the implicated process or mechanism, as well as theoretically irrelevant processes across procedurally different but theoretically linked paradigms, can be used to identify specific, differential deficits in schizophrenia. We agree with Knight and Silverstein's position that experimental psychological approaches are likely to have a more profound payoff in the study of schizophrenia than the typically test-based approach of neuropsychological studies (Strauss & Summerfelt, 1994).…”

“…Discriminant validity is indicated by the absence of relationships between measures that are presumed to measure theoretically unrelated constructs. Consideration of discriminant validity, we believe, is much less evident in studies that compare patients with schizophrenia to controls on neuropsychological tests (Strauss & Summerfelt, 1994). The presence of generalized psychological deficits in schizophrenia (Chapman & Chapman, 1973) complicates the demonstration of discriminant validity, as we discuss later.…”

“…In schizophrenia research there seems to be a tacit assumption that the probability of specific brain damage given psychological test results is symmetrical with the probability of specific test results given a specific brain abnormality. However, sensitivity and specificity are not the same for y on x as for x on y unless the correlation between x and y is 1.0 (Strauss & Summerfelt, 1994).…”

“…The clinical neuropsychogical approach has useful roles in diagnosis, prognosis, and treatment evaluation at a psychological level (Heaton et al, 1993;Keefe, 1995). For the reasons we have reviewed, however, it is not a useful method for advancing theoretical knowledge about brain dysfunction in relation to psychological deficits in schizophrenia (Keefe, 1995;Strauss & Summerfelt, 1994).…”

Cognition in schizophrenia and schizo-affective disorder: impairments that are more similar than different

“…One reason for lack of consistency across studies may be that cognitive function was evaluated with clinical neuropsychological tests that might be sensitive to multiple sources of impairment (Strauss & Summerfelt, 1994), including non-specific factors such as motivation. Thus, it is possible that the similarities or differences between schizophrenia and schizo-affective disorder would be more obvious or clearly interpretable if cognitive function were examined using finer-grained measures that allowed selective examination of specific cognitive mechanisms.…”