Electroconvulsive therapy increases hippocampal and amygdala volume in therapy refractory depression: a longitudinal pilot study.

Electroconvulsive therapy (ECT) is the most potent biological therapy in depression. Animal studies suggest that ECT acts via neuroplasticity effects on limbic structures involved in the pathophysiology of depression but in vivo evidence at the human system level is scarce. Therefore, the aim of the present study was to investigate the effect of ECT on hippocampus and amygdala volume in 15 antidepressant-free patients with treatment refractory depression (seven males, range 42-63 years). ECT treatment was successful as indexed by a significant decrease in depressive symptoms (t14=13.6; p<0.001). Analysis of normalized volumetric data before and after ECT treatment revealed a significant volume increase of both hippocampus and amygdala (minimum p<0.005) with no evidence for a change in global brain volume. Though this change in volume cannot be clearly related to treatment effects, ECT is associated with broader neurotrophic effects other than mere adult neurogenesis in the hippocampus, which has been previously suggested as a core mechanism on the basis of animal data.