Schatz J
Department of Psychology, Washington University of St. Louis, Missouri, USA.
Schizophr Res. 1998 Feb 27;30(1):41-9. doi: 10.1016/s0920-9964(97)00125-4.
The issue of generalized vs specific cognitive deficits in schizophrenia was explored by examining reaction time data from 40 published studies with 196 reaction time conditions. Using a regression-based approach, the proportional relationship between the response times of groups with schizophrenia was compared with those of age-matched, healthy comparison groups. Through this method, the extent to which deficits in processing efficiency are explained by a single factor, general processing speed, was compared with possible domain specific or task specific deficits. The results suggest that, overall, the data conforms well to a general linear slowing model which accounts for 87% of the variance in reaction time performance. Some additional variance, however, is accounted for by different degrees of linear slowing for three types of tasks: tasks involving selective attention/inhibition showed the most slowing (2.3-times slower for schizophrenia), followed by lexical tasks (1.8-times slower for schizophrenia), and finally, non-lexical tasks showed the least slowing (1.4-times slower for schizophrenia). This pattern is distinct from other groups showing generalized slowing, such as older adults, and suggests a unique pattern of information processing deficits in schizophrenia.
