2 Neuroscience2.12 Neurobiology of specific treatments
2.12.3 Neurobiology of ECT
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Written by Resident Doctor Committee · Published
New in the 2027 syllabus
The College added this topic for exams from January 2027.
What ECT is
Electroconvulsive therapy (ECT) uses an electrical stimulus to cause a controlled seizure in the brain. It is given under general anaesthesia with a muscle relaxant.
Judge the electrical dose against the patient's seizure threshold (the lowest dose that produces a seizure). Electrode placement and pulse characteristics affect both how well ECT works and how much cognitive harm it causes.
How it might work
The seizure sets off changes across widespread brain networks. It does not target a single neurotransmitter or one damaged area of the brain.
Proposed mechanism | What it means |
|---|---|
Changes in network connectivity | May change abnormal interactions within mood circuits |
Neurotrophic and synaptic effects | Experimental and imaging findings support the idea that ECT works through plasticity (the brain's ability to change its connections) |
Changes in inhibitory and excitatory signalling | Repeated treatments change the seizure threshold and how excitable the networks are |
Neuroendocrine changes | Hormonal responses happen straight after treatment, but they do not show how ECT works |
We still do not fully understand how ECT relieves depression. A biological change seen after ECT is not necessarily what causes the improvement.
Clinical implications
Indications: ECT may be right in severe depression when a rapid response is needed, when it helped before, or when other treatments have not worked.
Assessment and consent: cover anaesthetic risk, physical illness, cognition and the risks of leaving the illness untreated.
EEG monitoring: the muscle relaxant reduces visible convulsive movement, so electroencephalography (EEG) is used to check seizure activity in the brain.
Adequacy of treatment: seizure duration alone does not show whether treatment is adequate. Base the review on clinical response, seizure quality and adverse effects.
Cognitive effects: disorientation straight after treatment, and difficulty learning new information or recalling autobiographical memories (memories of one's own life). Some memory loss can persist.
Electrode placement and pulse width affect the balance between benefit and cognitive effects. So do the dose and the individual patient's vulnerability.
Continuation treatment is usually needed after a successful acute course, because getting better does not remove the risk of relapse.