Neurocognitive deficits or stress overload: Why do individuals with schizophrenia show poor performance in neurocognitive tests?

TY - JOUR

T1 - Neurocognitive deficits or stress overload: Why do individuals with schizophrenia show poor performance in neurocognitive tests?

AU - Krkovic, Katarina

AU - Moritz, Steffen

AU - Lincoln, Tania M

N1 - Copyright © 2016. Published by Elsevier B.V.

PY - 2017/5

Y1 - 2017/5

N2 - 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.

AB - 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.

U2 - 10.1016/j.schres.2016.11.002

DO - 10.1016/j.schres.2016.11.002

M3 - SCORING: Journal article

C2 - 27838097

VL - 183

SP - 151

EP - 156

JO - SCHIZOPHR RES

JF - SCHIZOPHR RES

SN - 0920-9964

ER -