In patients with major depressive disorder (MDD), suicidal ideation (SI) may be a clinically important moderator of frontal alpha asymmetry (FAA), according to the results of a study published in Clinical Psychopharmacology and Neuroscience. Recognizing that FAA of electroencephalography (EEG) has been examined to distinguish patients with MDD from healthy controls, the investigators sought to evaluate the influence of FAA on the relationship among patients with MDD with and without SI.
They recruited patients with MDD from the Department of Psychiatry in Inje University Ilsan Paik Hospital, Goyand, Korea, as well as healthy controls from social communities around the hospital. A total of 67 patients with MDD, 23 of whom had SI and 44 without SI, were enrolled in the study. The mean patient age was 38.67 years. These participants were compared with 60 healthy controls, with a mean age of 34.83 years.
In all participants, resting state EEG was obtained with the individuals’ eyes open. FAA was calculated as a lateralized index of alpha power in the frontal brain region. Scores on the Hamilton Rating Scale for Anxiety and Depression were assessed (HAM-A and HAM-D, respectively).
Symptom severity among the participants ranged from mild to severe in those with MDD both with and without SI, with no significant difference in symptom scales reported between the groups. FAA was significantly higher (ie, increased alpha power in the left frontal region) in the MDD group with SI than in the healthy control group (P =.023). No significant difference was observed, however, between those in the MDD group without SI and healthy controls
In all participants with MDD, a significant association was demonstrated between HAM-D scores and FAA (P =.008). A significant correlation also was shown between HAM-A scores and FAA (P =.009), thus suggesting that higher alpha power in the left midfrontal region is indicative of higher levels of anxiety and decreased levels of brain activity in that region. Further, the FAA was negatively correlated with HAM-D scores (P =.011), indicating that lower alpha power in the left lateral frontal region is reflective of higher levels of depression and increased levels of brain activity in that region.
A major limitation of the current study is the fact that the sample size of the patients with MDD with SI was relatively smaller than that of the other groups. In addition, the number of male participants was relatively small; thus, the effect of sex was unclear. The investigators concluded, however, that the results of the current study offer a starting point for future studies on FAA, thus demonstrating the importance of SI as a significant covariate.
Roh S-C, Kim JS, Kim S, Kim Y, Lee S-H. Frontal alpha asymmetry moderated by suicidal ideation in patients with major depressive disorder: a comparison with healthy individuals. Clin Psychopharmacol Neurosci. 2020;18(1):58-66.