T85. Frontal EEG Asymmetry Evoked by Sad Movies Predicts Relapses After Antidepressant Discontinuation

Background Antidepressant discontinuation is associated with a high risk of relapse. Robust predictors of relapse risk after antidepressant discontinuation could support clinical decision-making and possibly help reduce long-term prescriptions. Here, we examined whether frontal EEG asymmetry in the alpha band evoked by sad movies might index relapse risk after antidepressant discontinuation. Methods We recruited 35 healthy control subjects and 47 individuals who had achieved stable remission from Major Depressive Disorder while taking antidepressants, and were now intent on discontinuing them. Participants were tested prior to discontinuation and followed up for 6 months after discontinuation to ascertain relapses. All participants underwent EEG recording while viewing sad and neutral movie clips. We compared frontal asymmetry in alpha band power (8-13 Hz) at electrodes F5/F6 during neutral movies vs sad movies. Results Patients with remitted MDD did not differ in sadness-induced frontal asymmetry from healthy controls at electrodes F5/6. However, those who went on to relapse (n=14) after discontinuation did differ significantly from those who remained stable (n=33) over the observation period (p=0.004, Cohen's d'=0.93). Simple thresholding of the F5/6 asymmetry could be used to predict relapse with an accuracy of 83% (AUC 0.71). Conclusions EEG signals from a pair of frontal electrodes during the viewing of sad movies prospectively distinguished those who would and would not go on to relapse after antidepressant discontinuation. This simple procedure has potential to be translated for clinical use and warrants further investigation.