Electroconvulsive Therapy - Mechanism of Action

Mechanism of Action

The aim of ECT is to induce a therapeutic clonic seizure (a seizure where the person loses consciousness and has convulsions) lasting for at least 15 seconds. Although a large amount of research has been carried out, the exact mechanism of action of ECT remains elusive. ECT doctors claim it may "jumpstart the brain", helping boost neurotransmission, while others like Peter Breggin, claim it causes the "euphoric" effects similar to the effects found in "closed head injury" or people with fresh traumatic brain injury. The main reasons for this are that the human brain cannot be studied directly before and after ECT and therefore scientists rely on animal models of depression and ECT, with major limitations. While animal models are acknowledged to model merely aspects of depressive illness, human and animal brains are very similar at a molecular level, enabling detailed study of the molecular mechanisms involved in ECT.

There is a vast literature on the effects of Electroconvulsive Shock (ECS) in animals. In animal models of depression, particularly "learned helplessness" and "social defeat", there is evidence of pruning of normally dense synaptic connections in the hippocampus, a richly connected area deep in the temporal lobe which is vital in controlling both mood and memory.