Department of Psychology, University of Deusto, Bilbao, Spain.
Schizophr Res. 2012 Mar;135(1-3):72-8. doi: 10.1016/j.schres.2011.12.004. Epub 2012 Jan 5.
Decreased processing speed (PS) is a key feature of schizophrenia with respect to cognition, functional outcome and clinical symptoms. Our objective was to test whether PS slowing mediates other neuropsychological deficits among patients with chronic schizophrenia.
One hundred patients with schizophrenia and 53 healthy adults completed a series of neuropsychological measures that assess six cognitive domains. In addition to PS these included attention, verbal memory, visual memory, working memory, and executive functioning. Confirmatory factor analysis (CFA) was used to evaluate the fit of the 6-factor model. The cognitive performances of both groups were compared before and after controlling for the effect of PS, but also after controlling for the effect of each cognitive factor at a time. Finally, the PS-related variance was removed and the effect of the other cognitive factors was tested again.
CFA supported the hypothesized 6-factor cognitive structure. As expected, the patients and controls differed on all cognitive measures. However, after controlling for the effects of PS, group differences on the other five cognitive factors decreased substantially. Controlling for other factors produced smaller attenuation of group differences, and these effects were also partially accounted for by decreased PS.
PS deficits account for most of the differences in cognition between patients with schizophrenia and healthy controls. PS slowing appears to be a core feature of schizophrenia, one that underlies impairments of working memory, executive functioning, and other abilities.
处理速度（PS）降低是精神分裂症认知、功能结果和临床症状的一个关键特征。我们的目的是测试 PS 减慢是否在慢性精神分裂症患者的其他神经认知缺陷中起中介作用。
100 名精神分裂症患者和 53 名健康成年人完成了一系列神经心理学测试，评估了六个认知领域。除了 PS 之外，这些测试还包括注意力、言语记忆、视觉记忆、工作记忆和执行功能。验证性因子分析（CFA）用于评估 6 因素模型的拟合度。在控制 PS 效应的同时，比较了两组的认知表现，但也在一次控制每个认知因素的效应后进行了比较。最后，去除 PS 相关的方差，并再次测试其他认知因素的效果。
CFA 支持假设的 6 因素认知结构。正如预期的那样，患者和对照组在所有认知测试上都存在差异。然而，在控制 PS 效应后，两组在其他五个认知因素上的差异显著降低。控制其他因素产生的组间差异衰减较小，而这些影响也部分归因于 PS 降低。
PS 缺陷解释了精神分裂症患者和健康对照组之间认知差异的大部分原因。PS 减慢似乎是精神分裂症的一个核心特征，它是工作记忆、执行功能和其他能力受损的基础。
