Increased myo-inositol level in dorsolateral prefrontal cortex in migraine patients with major depression

Although the comorbidity between migraine and major depressive disorder (MDD) has been recognized, the pathophysiology remains unclear. The dorsolateral prefrontal cortex (DLPFC) is a well-known neural substrate for MDD. We investigated the relationship between brain metabolites in DLPFC and comorbid MDD in migraine patients.

We recruited migraine patients from a tertiary headache clinic. A board-certified psychiatrist conducted a structured interview for MDD diagnosis. The severity of depression was evaluated by the Beck Depression Inventory (BDI). Thirty migraine patients (five men, 25 women; mean age: 40.4 ± 12.4 years) completed the study, and 16 of them were diagnosed with MDD. All patients underwent a magnetic resonance spectroscopy (MRS) examination focusing on bilateral DLPFC. The ratios of N-acetylaspartate (NAA), choline (Cho), and myo-inositol (mI) to total creatine (tCr) were compared between migraine patients with and without MDD, and were correlated with BDI scores.

Relative to patients without MDD, migraine patients with MDD had higher mI/tCr ratios in the bilateral DLPFC ( p = 0.02, left; p = 0.02, right, Mann-Whitney U test). The mI/tCr ratios in the right DLPFC were positively correlated with BDI scores ( r = 0.52, p = 0.003). The NAA/tCr and Cho/tCr ratios did not differ between migraine patients with and without MDD.

Increased mI/tCr within the DLPFC might be associated with the presence of MDD in migraine patients.