Krkovic Katarina, Moritz Steffen, Lincoln Tania M
Department of Clinical Psychology and Psychotherapy, University of Hamburg, Germany.
Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Germany.
Schizophr Res. 2017 May;183:151-156. doi: 10.1016/j.schres.2016.11.002. Epub 2016 Nov 9.
Poor performance in neurocognitive tasks is consistently found across studies in all stages of schizophrenia spectrum disorders and is interpreted as an underlying, brain function-related, neurocognitive deficit. However, neurocognitive test performance in schizophrenia might be compromised by patients' increased stress level. We investigated group-differences in neurocognitive performance while accounting for psychophysiological (salivary cortisol, heart rate, skin conductance level) and self-reported stress. We included 35 patients with schizophrenia, 29 participants with attenuated psychotic symptoms, 26 first-degree relatives of individuals with schizophrenia and 28 healthy controls. Participants completed a neurocognitive test battery that assessed processing speed, task switching, attention, working memory, verbal episodic memory, and verbal comprehension. Multivariate analyses of covariance (MANCOVA) were calculated to test for main effects of group on neurocognitive performance thereby not accounting versus accounting for confounding effects of stress. As expected, patients with schizophrenia scored lower than the other groups in all neurocognitive domains. Participants with attenuated psychotic symptoms, first-degree relatives and healthy individuals did not differ from each other in their performance. After accounting for heart rate and self-reported stress, the multivariate effect of group on neurocognition remained significant, but was rendered non-significant for specific domains - working memory capacity, episodic memory, and long-term memory. The findings imply that stress is relevant to neurocognitive performance and this should be taken into account when interpreting the origin of performance deficits in schizophrenia patients.
在精神分裂症谱系障碍的各个阶段的研究中，均一致发现患者在神经认知任务中的表现较差，这被解释为一种潜在的、与脑功能相关的神经认知缺陷。然而，精神分裂症患者的神经认知测试表现可能会因患者压力水平的升高而受到影响。我们在考虑心理生理因素（唾液皮质醇、心率、皮肤电导率水平）和自我报告的压力的同时，研究了神经认知表现的组间差异。我们纳入了35名精神分裂症患者、29名有精神病性症状缓解的参与者、26名精神分裂症患者的一级亲属和28名健康对照者。参与者完成了一组神经认知测试，评估了处理速度、任务切换、注意力、工作记忆、言语情景记忆和言语理解。计算多变量协方差分析（MANCOVA）以检验组对神经认知表现的主要影响，从而不考虑与考虑压力的混杂效应。正如预期的那样，精神分裂症患者在所有神经认知领域的得分均低于其他组。有精神病性症状缓解的参与者、一级亲属和健康个体在表现上彼此没有差异。在考虑心率和自我报告的压力后，组对神经认知的多变量效应仍然显著，但在特定领域——工作记忆容量、情景记忆和长期记忆方面变得不显著。研究结果表明，压力与神经认知表现相关，在解释精神分裂症患者表现缺陷的根源时应考虑到这一点。
