Vitamin D: An Overlooked Parameter in Studies of Depression Using Optic Coherence Tomography.

Introduction: The relationship between depression and inflammation and the resulting vascular/neuronal damage have been demonstrated in recent studies. In this study we aimed to investigate inflammation and the possible degeneration that can be caused by depression and accompanying vitamin D deficiency using a non-invasive imaging method of optical coherence tomography (OCT). Methods: Twenty-four healthy controls and 42 drug free major depressive patients matched for age, sex and eye measurements were compared in terms of vitamin D, C Reactive Protein (CRP) and OCT parameters. The Hamilton Depression Rating Scale (HAM-D), The Clinical Global Impressions Scale (CGI) and Global Assessment of Functioning Scale (GAF) were used to assess disease severity. Results: CRP level and choroidal thickness in the major depression group were significantly higher than the healthy controls. Vitamin D level and the ganglion cell layer (GCL) volume was significantly lower in the major depression group compared to healthy controls. Positive correlation was found between HAM-D and CRP in major depressive patients; a negative correlation was found between current attack duration and GCL volume. CGI was positively correlated with CRP and HAM-D. GAS was negatively correlated with CRP and HAM-D. Conclusion: It has been shown that major depression might be an inflammatory disorder with possible degenerative processes observed with OCT and CRP measurements. But longitudinal follow up studies are needed to demonstrate a cause and effect relationship.