Major Depressive Disorder (MDD) is a common mood disorder characterized by persistent sadness, loss of interest and cognitive impairment. Emerging evidence suggests that vitamin D may exert neuroprotective and mood-regulating effects by influencing serotonin synthesis, modulating inflammation and supporting neuronal function. Vitamin D deficiency is frequently observed in MDD patients and has been linked to greater symptom severity and poorer treatment outcomes. Quantitative electroencephalography (QEEG) is a non-invasive tool for assessing brain electrical activity. Alterations in QEEG pattern such as increased theta and reduced alpha power have been reported in patients with MDD , reflecting disrupted cortical processing and emotional regulation. Although interest in the role of vitamin D in mental health is increasing, the direct effect of vitamin D supplementation on QEEG parameters in MDD patients with hypovitaminosis D is not well explored. This study aims to evaluate whether vitamin D supplementation can modulate brain wave activity in female patients with MDD and hypovitaminosis D. Therefore providing insight into its neurophysiological and therapeutic significance.

Objective To evaluate the effect of vitamin D supplementation on quantitative EEG parameters in female MDD patients with hypovitaminosis D.

Methods This experimental study (self-controlled trial) will be conducted by the Department of Physiology, Bangladesh Medical University, Shahbagh, Dhaka from September 2025- August 2026. For this study, a total number of 39 female patients with MDD (age 20-40 years) will be enrolled as study participants according to selection criteria. DASS-21 scoring and baseline EEG will be recorded (pre vitamin D group). After that the participants will be supplemented vitamin D capsule (50,000IU/week) for 8 weeks. After completion of 8 weeks, DASS-21 scoring and EEG will be recorded and that will be designated as post vitamin D group.

To analyze brain electrical activities, the band power of alpha, beta, theta, and delta brainwaves will be measured using an EEG Data gathering Device, the EEG Traveler BrainTech 32+ CMEEG-01 from India. The BT40 analysis software will be used to perform power spectral analysis of the EEG Data. Mean ± SD will be used to express the Data. For statistical analysis, if data are normally distributed, to compare the mean values between the pre intervention and post intervention sessions, recorded as pre vitamin D group and post vitamin D group, paired- samples t test will be done. The P value of ≤0.05 will be accepted as statistically significant. SPSS for Windows (version 25) will be used for the statistical analysis.

The findings of this study are expected to provide quantitative evidence regarding the neurophysiological effects of vitamin D supplementation in female MDD patients with hypovitaminosis D.

Inclusion Criteria:

• • Diagnosed case of MDD by a psychiatrist form the Department of Psychiatry OPD, based on the Diagnostic and Statistical Manual of Mental Disorder, 5th edition (DSM-V) criteria set by the American Psychiatric Association.

  • Hypovitaminosis D ( serum 25 ( OH )D <30 ng/ml )
  • Age range : 20-40 years
  • Sex: female
  • Patients must be on a stable dose regimen, without any changes in drug type or dosage, for at least 6 months prior to enrollment , to minimize confounding effects on EEG outcomes.
  • Not receiving any medication that affect central nervous system other than anti-depressant drugs

Exclusion Criteria:

• Active smokers
• Known hypersensitivity to vitamin D
• Presence of any other serious psychiatric or systemic illness
• Pregnant women
• Lactating women
• Women taking hormonal contraceptives.
• Individuals already taking vitamin D supplements
• Patients with hypercalcemia

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