Evaluation of the Relationship between Depression and the Volume of Olfactory Regions by Parcellation Method

Scientific studies in the literature have demonstrated olfactory loss and reduced olfactory bulb volume in individuals with major depressive disorder. This study aims to evaluate the correlation between major depressive disorder and olfactory region volume. In the study, Magnetic Resonance İmaging (MRI) images of 33 patients with major depressive disorder and 33 healthy controls from Balıkesir University Hospital's Mental Health Clinic were retrospectively analyzed. In the obtained MRI series, the volumes of the amygdala, fusiform gyrus, anterior commissure, olfactory radiation, and entorhinal area, which are involved in olfaction, were measured using a parcellation method. All data were transferred to SPSS and analyzed quantitatively. The statistical analysis of the variables examined in the study revealed that the right and left amygdalae tend to be smaller in individuals with illness. It was determined that there was a positive correlation among the parameters evaluated in the study: left amygdala, left entorhinal area, right and left fusiform gyrus volumes, and the Hamilton Depression Scale. As a result of the research, it was revealed in the direction of morphometric analysis that there is a negative relationship between major depressive disorder and olfactory regions. The data obtained in light of these findings will contribute to understanding the cause-and-effect relationship between depression and loss of smell; for clinicians, it is expected to serve as a guide in diagnosis and treatment.