The following is a summary of “One size does not fit all: notable individual variation in brain activity correlates of antidepressant treatment response,” published in the April 2024 issue of Psychiatry by Wijk et al.

Researchers conducted a retrospective study identifying individual differences in electroencephalography (EEG) characteristics associated with antidepressant treatment response,  as previous group-based analyses might have masked this variability.

They collected resting-state EEG data and Montgomery-Åsberg Depression Rating Scale (MADRS) symptom scores from 43 depressed patients before, at 1 and 12 weeks of pharmacotherapy. Utilizing Partial Least Squares (PLS), distinguished differences in EEG connectivity (Weighted Phase Lag Index) and complexity (Multiscale Entropy) between eventual medication responders and non-responders while also identifying group patterns in individual patients.

The results showed that responders exhibited reduced alpha and increased beta connectivity alongside early, widespread decreases in complexity during treatment. Non-responders displayed an opposing connectivity pattern, with later, spatially confined decreases in complexity. Similar to prior research, our group analyses revealed significant differences between patient groups with distinct treatment outcomes. The EEG characteristics at the group level were only detected in approximately 40-60% of individual patients, as quantitatively assessed by correlating spatiotemporal brain patterns between groups and personal results and by visualization evaluated by independent raters.

Investigators concluded that substantial individual variability exists in EEG response to antidepressants, highlighting the need to consider this in future studies for clinical translation.

Source: frontiersin.org/journals/psychiatry/articles/10.3389/fpsyt.2024.1358018/full