Brief Research Report ARTICLE
THE ASSOCIATION BETWEEN CARDIO-RESPIRATORY FITNESS AND COGNITION APPEARS NEITHER RELATED TO CURRENT PHYSICAL ACTIVITY NOR MEDAITED BY BRAIN-DERIVED NEUROTROPHIC FACTOR IN A SAMPLE OF OUTPATIENTS WITH SCHIZOPHRENIA
- 1Clinical Mental Health and Drug Treatment, Vestfold Hospital Trust, Norway
- 2Department of Psychology, Faculty of Social Sciences, University of Oslo, Norway
- 3Faculty of Humanities, Sports and Educational Science, University of South-Eastern Norway, Norway
- 4Norwegian Centre for Mental Disorders Research, Faculty of Medicine, University of Oslo, Norway
- 5Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Norway
- 6Research Institute of Internal Medicine, Oslo University Hospital, Norway
- 7Faculty of Health Sciences, UiT The Arctic University of Norway, Norway
Objective: We investigated whether levels of current physical activity (PA) contribute to the established relationship between cardio-respiratory fitness (CRF) and cognition in schizophrenia, and whether brain-derived neurotrophic factor (BDNF) or its precursor proBDNF mediate this relationship.
Method: Sixty-one outpatients with schizophrenia spectrum disorders participated. Neurocognition was assessed with the Wechsler Adult Intelligence Scale (WAIS) and nine subtests from the MATRICS battery comprising a neurocognitive composite score (NCS). CRF was assessed with peak oxygen uptake (VO2peak) measured directly during a maximum exercise test. Current PA levels were objectively assessed by an accelerometer worn for four consecutive days. BDNF and proBDNF were measured in fasting blood. Four serial parallel mediation analyses and two additional parallel mediation analyses were conducted, while controlling for age and sex at all levels.
Results: No direct effects were found between PA measures and WAIS or NCS. No significant mediating effects of CRF or BDNF/proBDNF were detected.
Conclusion: The results do not support the hypothesis that PA contributes to the naturally occurring relationship between CRF and cognition in schizophrenia, or the hypothesis that BDNF or proBDNF mediate this relationship. The results arguably support the assumption that the association between CRF and cognition in schizophrenia is established developmentally early.
Keywords: psychosis, Scizophrenia , Cognition, Exercise, CRF, BDNF, Physical, activity
Received: 17 Jun 2019;
Accepted: 02 Oct 2019.
Copyright: © 2019 Holmen, Egeland, Andersen, Mordal, Andreassen, Ueland, Bigseth, Bang-kittilsen and Engh. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Mr. Tom L. Holmen, Clinical Mental Health and Drug Treatment, Vestfold Hospital Trust, Tønsberg, Norway, email@example.com