Hippocampal volume changes following electroconvulsive therapy: a systematic review and meta-analysis

Area of Science:

• Neuroscience
• Psychiatry
• Radiology

Background:

• Major Depressive Disorder (MDD) is associated with reduced hippocampal volume.
• Electroconvulsive therapy (ECT) is a highly effective MDD treatment, but its mechanisms are unclear.
• ECT has been shown to promote neuroplasticity and increase hippocampal volume in animal models.

Purpose of the Study:

• To investigate the effects of ECT on hippocampal volume in humans through a meta-analysis.
• To determine if ECT-induced changes in hippocampal volume correlate with clinical improvement in MDD.

Main Methods:

• A systematic search of PubMed was conducted for studies measuring hippocampal volume before and after ECT.
• A random-effects meta-analysis was performed using standardized mean difference (SMD) to assess changes in hippocampal volume.
• Nine studies with a total of 174 participants were included in the analysis.

Main Results:

• Significant bilateral increases in total hippocampal volume were observed after ECT treatment (SMD=1.10).
• Both right (SMD=1.01) and left (SMD=0.87) hippocampal volumes showed significant increases post-ECT.
• No significant correlation was found between the degree of depression symptom improvement and the change in total hippocampal volume.

Conclusions:

• ECT treatment leads to consistent, bilateral increases in hippocampal volume.
• Further large-scale, multisite studies are needed to clarify the relationship between ECT-induced volumetric changes, clinical outcomes, and cognitive effects.