Effekten av fysisk aktivitet på biomarkörer för klinisk depression, en strukturerad, kvantitativ litteraturanalys med implikationer för framtida behandling.

Sammanfattning: The aim of this study was to do a structured analysis of the literature on biomarkers for major depressive disorder (MDD) and how these biomarkers may be modulated by physical activity (PA). This with implications for future treatment of mild to moderate MDD with PA. The method was quantitative and followed guidelines for conducting a simplified meta-analysis. The study analyzed 37 randomized controlled trials (RCTs) that covered a total of 911 individuals doing PA. Articles on biomarkers that are previously well established in their relationship with MDD were collected in a structured way, following strict criteria. Results were achieved using statistical methods for calculating the average effect size (ES) and average mean difference (Δ%) for the biomarkers as a result of PA. BDNF showed an effect size of 0.81 ± 1.09 and an average mean difference of +61.7 ± 112.20 %. CRP showed an effect size of 0.35 ± 0.28 and an average mean difference of -18 ± 13.69 %. Cortisol showed an effect size of 0.09 ± 0.75 and an average mean difference of -2.9 ± 17.30 %. Serotonin showed an effect size of 0.39 ± 0.54 and an average mean difference of -11.53 ± 21.10 %. Testosterone showed an effect size of 0.59 ± 1.46 and an average mean difference of +6.50 ± 20.04 %. The conclusion was that PA had a large effect on BDNF and can be used as a diagnostic- and follow-up tool for patients with MDD treated with PA. PA has a small but consistent effect on CRP which therefore can be used in conjunction with other outcome measures to diagnose and follow up patients with MDD treated with PA. PA showed no effect on cortisol and can therefore be considered to be irrelevant as a diagnostic- and follow-up tool for patients with MDD treated with PA. PA had a small but relatively consistent effect on serotonin which therefore can be used in conjunction with other outcome measures to diagnose and follow up patients with MDD treated with PA. PA had a moderate and relatively inconsistent effect on testosterone which therefore can be used in conjunction with several other outcome measures to diagnose and follow up patients with MDD treated with PA. On the basis of these conclusions PA can be a valuable tool for improving some biomarkers for MDD (BDNF, CRP, serotonin & testosterone). Hopefully this study can provide a basis for further research as well as an addition to first line treatment for mild to moderate MDD with PA.