Electroconvulsive therapy · Lobeworks/17

Electroconvulsive therapy (ECT) is a treatment that induces a brief, controlled generalised seizure by passing an electric current between electrodes on the scalp while the patient is under general anaesthesia and muscle relaxation, used mainly for severe or treatment-resistant depression, where it is among the most ef

Electroconvulsive therapy. Electroconvulsive therapy (ECT) is a treatment that induces a brief, controlled generalised seizure by passing an electric current between electrodes on the scalp while the patient is under general anaesthesia and muscle relaxation, used mainly for severe or treatment-resistant depression, where it is among the most effective treatments known.

A course usually runs six to twelve treatments, given two or three times a week (twice weekly is common in the United Kingdom and much of Europe, three times in the United States, which acts faster at the cost of more memory impairment); over half of patients with depression reach remission. The anaesthetic keeps the patient asleep and a short-acting muscle relaxant such as succinylcholine keeps the body almost still, so the tonic-clonic discharge runs in the brain without the violent movement that once broke vertebrae; it is monitored on EEG. The method began in Rome in April 1938, when Ugo Cerletti and Lucio Bini replaced the chemically induced seizures then used in psychiatry with an electric current.

It turns the atlas's recurring danger into a tool. The generalised seizure, the excitation and inhibition balance lost in both hemispheres, is the active ingredient that protocols aim for, and across a course the seizure threshold tends to rise, which has led to the idea that part of its effect is anticonvulsant.

ECT resets the brain is a metaphor. The proposed mechanisms are concrete and none is settled: stronger neurotrophic signalling, the birth of new neurons (in rodents electroconvulsive seizures are the strongest known stimulus of adult neurogenesis), and changes in how large networks connect.

Its costs are memory and relapse: confusion right after a session and gaps in memory around the weeks of treatment, mostly recovering; and without continued treatment many patients relapse, so maintenance sessions, weekly to monthly, are common.

It differs from TMS in kind. TMS induces small currents in one patch of cortex in an awake patient and must not cause a seizure; ECT recruits the whole brain into one on purpose.

In ECT the seizure is the treatment.

What the epilepsy cards describe as a failure of control is produced here deliberately, briefly and under anaesthesia.

Questions: What separates electroconvulsive therapy from TMS? Both send energy through the skull, for opposite purposes. ECT passes current between scalp electrodes to start a generalised seizure, under general anaesthesia, two or three times a week for six to twelve sessions. TMS uses a magnetic pulse to induce a small current in one patch of cortex in an awake patient, each weekday for several weeks, and a seizure is the rare adverse event its safety rules exist to prevent. ECT is the stronger treatment for severe depression, at the cost of anaesthesia and memory effects; TMS is gentler and more focal, and weaker. How can a seizure induced on purpose be a treatment? In electroconvulsive therapy the generalised seizure is the active ingredient: the current is only the trigger, and the dose is adjusted until an adequate seizure appears on the EEG. It is made safe by general anaesthesia and a muscle relaxant, so the tonic-clonic discharge happens in the brain while the body barely moves. Why a seizure relieves severe depression is not settled; the candidates include stronger neurotrophic signalling, new hippocampal neurons in animal models and a rise in the seizure threshold across a course, which suggests the brain answers repeated seizures by strengthening its own inhibition.