Moritz Steffen, Woodward Todd S
Universitätsklinikum Hamburg-Eppendorf, Klinik für Psychiatrie und Psychotherapie, Hamburg, Germany.
Br J Clin Psychol. 2005 Jun;44(Pt 2):193-207. doi: 10.1348/014466505X35678.
Several studies have provided evidence for the claim that a subgroup of (schizophrenic) patients with current delusions share a jumping to conclusions (JTC) bias. The primary aim of the present study was to investigate whether currently deluded and non-deluded schizophrenic patients perform differently on three tasks tapping probabilistic reasoning.
Probabilistic reasoning was assessed in 31 schizophrenic patients, 28 psychiatric controls, and 17 healthy controls. In addition to the traditional draws to decision procedure, we employed two tasks for which participants had to judge, at each stage, the likelihood that beads come from either container (graded estimates procedure). Reaction times were recorded for the graded estimates procedure.
A JTC bias was displayed by 42% of the schizophrenic patients in the draws to decision condition, while 7% of the psychiatric patients and none of the healthy controls reached a decision after only one bead. A similar pattern of results was observed for the graded estimates procedure. This bias was more pronounced in deluded schizophrenic patients, although currently non-deluded patients also showed evidence for earlier decisions. A bias to over-adjust when confronted with potentially disconfirmatory evidence was confined to deluded schizophrenic participants. There was also evidence for an increase in JTC in the deluded group over the course of the tasks. No substantial group differences occurred with respect to reaction time parameters indicating that results are not attributable to impulsivity.
The findings provide further evidence for state and trait characteristics of abnormal reasoning in paranoid schizophrenia. Results are discussed in light of several competing explanations for JTC in schizophrenia.
多项研究为以下观点提供了证据，即当前存在妄想的（精神分裂症）患者亚组存在“急于下结论”（JTC）偏差。本研究的主要目的是调查当前存在妄想和不存在妄想的精神分裂症患者在三项涉及概率推理的任务中的表现是否不同。
对31名精神分裂症患者、28名精神科对照者和17名健康对照者进行概率推理评估。除了传统的抽取决策程序外，我们还采用了两项任务，在每个阶段，参与者必须判断珠子来自两个容器中任意一个的可能性（分级估计程序）。记录分级估计程序的反应时间。
在抽取决策条件下，42%的精神分裂症患者表现出JTC偏差，而精神科患者中有7%，健康对照者中无人在仅抽取一颗珠子后就做出决策。在分级估计程序中也观察到了类似的结果模式。这种偏差在存在妄想的精神分裂症患者中更为明显，尽管目前不存在妄想的患者也有证据表明其决策更早。面对潜在的反证时过度调整的偏差仅限于存在妄想的精神分裂症参与者。还有证据表明，在任务过程中，存在妄想的组中JTC有所增加。在反应时间参数方面没有出现实质性的组间差异，这表明结果并非归因于冲动性。
这些发现为偏执型精神分裂症异常推理的状态和特质特征提供了进一步的证据。根据对精神分裂症中JTC的几种相互竞争的解释对结果进行了讨论。
