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2026-06-30 PubMed

Magnesium Supplementation Significantly Boosts Cognitive Function in Fluoxetine-Treated Depression Patients

Effects of magnesium supplementation on serum brain-derived neurotrophic factor levels and cognitive function in patients undergoing fluoxetine therapy for depression.

Background

Cognitive dysfunction is a common and debilitating symptom of depression, often persisting even with antidepressant treatment. Brain-derived neurotrophic factor (BDNF) plays a crucial role in neuroplasticity, synaptic function, and cognitive processes, with lower levels frequently observed in depression. Current standard-of-care, such as selective serotonin reuptake inhibitors like fluoxetine, primarily targets mood symptoms but may not fully address cognitive deficits or restore optimal BDNF levels. Investigating adjunctive therapies that can enhance neuroplasticity and cognitive function, potentially by modulating BDNF, represents a significant gap in improving comprehensive outcomes for patients with major depressive disorder.

Study Design

This 6-week randomized controlled trial enrolled 40 outpatients, aged 18 to 50 years, diagnosed with depression and already receiving fluoxetine therapy. Participants were allocated to either a control group receiving fluoxetine alone or a treatment group receiving fluoxetine plus 350 mg of oral magnesium supplementation once daily. Assessments were conducted at baseline and after 6 weeks. Serum BDNF concentrations were quantified using an enzyme-linked immunosorbent assay kit from peripheral venous blood samples. Cognitive function was evaluated using the validated Indonesian version of the Montreal Cognitive Assessment (MoCA-Ina).

Results

Both groups showed significant improvements in MoCA-Ina scores from baseline to week 6 (both p < 0.001), but the improvement was substantially greater in the treatment group (4.8 vs 1.35, p < 0.001). This enhanced cognitive benefit was particularly evident in specific domains: attention improved from 2.90 to 4.05 (p < 0.001) and memory from 2.25 to 3.85 (p < 0.001) in the magnesium group. At week 6, scores were significantly higher in the treatment group for attention (4.05 vs 3.10, p = 0.002), memory (3.85 vs 2.70, p < 0.001), and orientation (5.75 vs 5.05, p < 0.001).

Key Findings

  • Magnesium supplementation improved overall MoCA-Ina scores by 4.8 points, significantly more than control (1.35 points, p < 0.001).
  • Significant improvements in attention (4.05 vs 3.10, p = 0.002), memory (3.85 vs 2.70, p < 0.001), and orientation (5.75 vs 5.05, p < 0.001) domains were observed in the magnesium group.
  • Serum BDNF levels did not significantly change between groups (p = 0.584).
  • Correlation between BDNF change and MoCA-Ina change was stronger in the magnesium group (ρ = 0.667, p = 0.001) than in the control group (ρ = 0.483, p = 0.031).

Why It Matters

Adding magnesium to existing fluoxetine therapy offers a simple, accessible, and potentially impactful strategy to address the often-overlooked cognitive deficits in depression. This finding suggests that a daily 350 mg oral magnesium dose could significantly enhance cognitive function, particularly attention and memory, beyond what fluoxetine alone provides. For individuals managing depression, this could translate to improved daily functioning and quality of life. While the exact mechanism linking magnesium to cognitive improvement without a significant change in overall serum BDNF levels requires further investigation, the stronger correlation between BDNF and MoCA-Ina changes in the treatment group hints at a more nuanced neurobiological effect. This opens avenues for optimizing existing antidepressant protocols with readily available supplements.


magnesium depression cognitive-function bdnf fluoxetine rct
Source: pubmed:42374947 · Ingested 2026-06-30 · Digest: gemini-2.5-flash