Brain-Symptom Associations of Oscillatory Functional Connectivity and PHQ9 Sub-Questions in Major Depressive Disorder

Major Depressive Disorder (MDD) is a highly heterogenous disorder shown to have alterations in resting state functional connectivity networks. The aim of this exploratory study was to investigate correlations between resting state functional connectivity and specific depression symptoms from the Patient Health Questionnaire 9 (PHQ9). The study included N=263 participants diagnosed with MDD who underwent the Mini-International Neuropsychiatric Interview (MINI) and the PHQ9 questionnaire. Fifteen-minute eyes-open resting state magnetoencephalography (MEG) recording was conducted using a 306-channel TRIUX system. Two forms of functional connectivity, phase synchrony (PS) and amplitude correlation (AC), were assessed. We found that four MDD symptoms were significantly correlated with resting state functional connectivity in a frequency and anatomy specific manner. Anhedonia was significantly correlated with beta-band PS node strength in up to 37% of cortical parcels. Psychomotor disturbance (PmD) was significantly negatively correlated with PS node strength in up to 19% cortical parcels. Low self-esteem was significantly correlated with beta-band AC node strength in up to 44% cortical parcels. Finally, fatigue was significantly correlated with delta-band PS in up to 7% cortical parcels. Significant parcels were mostly situated in the Default Mode Network, Somatomotor Network, Control Network, and Salience Ventral Attentional Network. Results are generally in-line with current literature, but point to a need for further investigation of individual depression symptoms.