Electroconvulsive therapy

Technique

Under anaesthesia and a muscle relaxant, a brief electrical stimulus causes a short, controlled seizure; a rapid-acting treatment for severe depression.

Updated Nov 13, 2026

Key points

Indications: severe or treatment-resistant depression, bipolar depression, suicidality, catatonia, refusal to eat or drink (malnutrition), and some cases of mania, schizophrenia and schizoaffective disorder.
Catatonia responds well to ECT, which can be combined with benzodiazepines.
It is usually safe and effective in pregnancy, with joint obstetric care and frequent fetal monitoring, and it is often useful in older adults who do not tolerate medicines.
Few conditions rule ECT out; a recent heart attack, a brain aneurysm and intracranial lesions call for caution and specialist assessment.
Main side effects: headache, upset stomach, muscle aches and confusion, and memory loss for events around the treatment, which usually improves over days to weeks.
Unilateral electrode placement carries a lower risk of memory loss than bilateral placement.

What it is

Electroconvulsive therapy (ECT) induces a brief generalized seizure under a short-acting anaesthetic and a muscle relaxant, so the body hardly moves. A course is usually about three sessions a week, typically 6 to 12 treatments, and many patients need maintenance sessions to prevent relapse. It is used for severe or treatment-resistant depression and bipolar depression, and when a rapid response is needed because of catatonia, suicidality or malnutrition; it is also used in some cases of mania, schizophrenia and schizoaffective disorder. Its main side effects are headache, muscle aches, confusion and memory loss around the time of treatment.

Key facts

The stimulus first causes a brief parasympathetic (vagal) slowing of the heart, then the seizure brings a catecholamine surge with a rise in heart rate and blood pressure.
Death directly caused by ECT is extremely rare; most serious risks come from the heart and the anaesthesia.
Neither dementia nor delirium is a contraindication; ECT is often useful in older adults.
Relapse after a successful course is common without continuation treatment; maintenance ECT ranges from weekly to every few months.

How it is done

Discuss benefits, risks and alternatives and obtain informed consent (or the legal substitute process if the patient lacks capacity).
Pre-treatment workup: medical history, examination, review of medicines that alter seizures, and anaesthetic assessment.
Fasting before the session; monitoring of heart rhythm, blood pressure and oxygen.
A short-acting intravenous anaesthetic is given, then a muscle relaxant so the seizure causes almost no movement.
Electrodes are placed on the scalp, on one side (unilateral) or both sides (bilateral).
A brief electrical stimulus produces a short generalized seizure.
The patient wakes and recovers under observation; headache, muscle aches, upset stomach and confusion are treated.
Sessions run about three times a week, typically 6 to 12 in all; mood and memory are tracked and maintenance is planned to prevent relapse.

When ECT is chosen, and why

Situation	Why ECT
Severe depression, refusal to eat or drink	Rapid response when life or health is at risk
Suicidality in depression	Used when a rapid response is needed
Catatonia	Effective; can be combined with benzodiazepines
Treatment-resistant depression	When medicines and psychotherapy have not helped
Mania, schizophrenia, schizoaffective disorder	Used in some cases

Test yourself

Think of the answer, then tap the question to see it.

Why is a muscle relaxant given during ECT?

So the induced seizure causes almost no body movement, preventing fractures and injury; anaesthesia keeps the patient asleep.

What is the main side effect of ECT?

Headache, muscle aches and confusion after sessions, and memory loss for events around the treatment, which usually improves over days to weeks.

What happens to the heart rate during an ECT session?

The stimulus first causes a brief vagal slowing of the heart; the seizure then brings a catecholamine surge with a faster heart rate and higher blood pressure.

What are three indications for ECT?

Severe or treatment-resistant depression, suicidality and catatonia (also malnutrition from refusal to eat and some cases of mania or schizophrenia).

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Educational content on behavior and the clinical relationship; not a diagnostic or treatment guide and no substitute for assessment by a health professional. If you or someone near you is at risk, seek help now from an emergency service or a mental-health helpline.

Sources: Brain Stimulation Therapies (National Institute of Mental Health (NIMH), 2024); Safety of electroconvulsive therapy in the context of physiological and medical complexity: A state-of-the art review (PCN Reports (PubMed Central), 2025).

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