An international research team led by the University of Granada has provided the first robust scientific evidence that depression is linked to significant disturbances in oxidative stress, supporting the view that depression should be regarded as a systemic disease affecting the whole body.
The findings, published in the Journal of Clinical Psychiatry, help explain the well-documented associations between depression and higher rates of cardiovascular disease, cancer, and premature mortality. By demonstrating measurable biochemical changes beyond the brain, this work highlights how depression involves body-wide physiological processes and points toward new directions for prevention and treatment.
The study was led by Sara Jiménez Fernández, a PhD candidate at the University of Granada and a psychiatrist at the Child and Adolescent Mental Health Unit at Jaén Medical Center in Spain. Co-authors include University of Granada psychiatry professors Manuel Gurpegui Fernández de Legaria and Francisco Díaz Atienza, with contributions from an international team including Christoph Correll from Zucker Hillside Hospital (New York, USA).
A meta-analysis of 3,961 people
This research is a meta-analysis that synthesizes data from 29 prior studies, together representing 3,961 participants. It is the most detailed analysis to date examining how depression alters oxidative stress markers throughout the body. Specifically, the study assessed an imbalance characterized by increases in markers of oxidative damage—most notably malondialdehyde (MDA), a biomarker of lipid peroxidation and membrane damage—and decreases in several antioxidant defenses, including uric acid, zinc, and the enzyme superoxide dismutase (SOD).
The meta-analysis examined concentrations of oxidative stress biomarkers in people diagnosed with major depressive disorder compared with healthy control participants. The pattern was consistent: elevated oxidative damage markers and reduced levels of several antioxidants. These biochemical shifts provide a plausible biological pathway linking depression with higher rates of physical illnesses and reduced life expectancy.
Effects of standard treatment on oxidative markers
Importantly, the researchers found that standard treatments for depression were associated with measurable biochemical improvements. After receiving usual clinical treatment, patients showed significantly reduced malondialdehyde levels—reductions large enough that treated patients’ MDA concentrations were not distinguishable from those of healthy comparison groups. In parallel, circulating levels of zinc and uric acid increased toward normal ranges following treatment.
However, not all antioxidant markers normalized. The activity of the enzyme superoxide dismutase remained reduced in depressed patients despite conventional treatment, indicating that some aspects of antioxidant defense may be more resistant to change or may require targeted interventions.
Clinical and research implications
By documenting a clear oxidative imbalance in depression and showing partial normalization after treatment, this meta-analysis strengthens the case for viewing depression as a systemic condition with measurable peripheral biomarkers. These findings may help explain why depression commonly co-occurs with chronic physical diseases and why it contributes to earlier mortality.
From a therapeutic perspective, the results point to potential new targets: interventions that specifically address oxidative damage or bolster antioxidant defenses could complement existing treatments. Future research should investigate whether antioxidant-focused therapies can further reduce oxidative damage, restore enzymes such as superoxide dismutase, and improve long-term outcomes for people with depression.
Source: Manuel Gurpegui Fernández de Legaria – University of Granada
Image Credit: Image is in the public domain.
Original Research: The study will appear in Journal of Clinical Psychiatry.