Characterization of gray matter volume changes from one week to 6 months after termination of electroconvulsive therapy in depressed patients

Background

Increased gray matter volume (GMV) following electroconvulsive therapy (ECT) has been well-documented, with limited studies reporting a subsequent decrease in GMV afterwards.

Objective

This study characterized the reversion pattern of GMV after ECT and its association with clinical depression outcome, using multi-site triple time-point data from the Global ECT-MRI Research Collaboration (GEMRIC).

Methods

86 subjects from the GEMRIC database were included, and GMV in 84 regions-of-interest (ROI) was obtained from automatic segmentation of T1 MRI images at three timepoints: pre-ECT ($T_0$), within one-week post-ECT ($T_1$), and one to six months post-ECT ($T_2$). RM-ANOVAs were used to assess longitudinal changes and LMM analyses explored associations between GMV changes and demographical and clinical characteristics.

Results

63 of the 84 ROIs showed a significant increase-and-decrease pattern (RM-ANOVA, Bonferroni corrected p < 0.00059). Post hoc tests indicated a consistent pattern in each of these 63 ROIs: significant increase from $T_0$ to $T_1\text{in}\text{GMV}$, followed by significant decrease from $T_1$ to $T_2$ and no difference between $T_0$ and $T_2$, except for both amygdalae, right hippocampus and pars triangularis, which showed the same increase and decrease but GMV at $T_2$ remained higher compared to $T_0$. No consistent relationship was found between GMV change pattern and clinical status.

Conclusion

The GEMRIC cohort confirmed a rapid increase of GMV after ECT followed by reversion of GMV one to six months thereafter. The lack of association between the GMV change pattern and depression outcome scores implies a transient neurobiological effect of ECT unrelated to clinical improvement.