Electroconvulsive therapy, as the name suggests, consists of an electric shock and a seizure. Nowadays, if you are given ECT in most Western countries, you will be given an anaesthetic and muscle paralysing drugs so you won’t actually have a full-blown convulsion but events in the brain – the seizure – are still the same. And it is the seizure that most psychiatrists consider to be the main therapeutic ingredient of ECT. Before ECT was first used in 1938, convulsive therapy had been in use in the treatment of mental illness for several years, with the seizures being induced by drugs. Nobody knows quite why seizures should be therapeutic; there is vague talk about altering ‘chemical messengers in the brain’ or ‘re-setting’ the brain.
In the early days of ECT psychiatrists were divided about whether it was the seizure or the electric shock that caused the memory problems associated with the treatment. Then fifty years ago Swedish psychiatrist Jan-Otto Ottosson did some experiments and decided that it was the electric shock that was the major contributory factor to memory problems after ECT. Over the following decades this theory became widely accepted, with psychiatrists believing that memory loss was related not so much to the amount of electricity used but to the degree to which it exceeded an individual’s seizure threshold. However when ECT machines that delivered weaker shocks were introduced psychiatrists complained that even when patients had seizures their symptoms were not improving, and the machines were sent back to the manufacturers to have their output increased. The idea that just enough electricity to produce a seizure was needed was abandoned, and replaced by ideas that the optimal amount was about one-and-a-half times to twice an individual’s seizure threshold (for bilateral ECT that is – for unilateral ECT the values are different). Above this level, patients would be at risk of greater memory loss without any additional therapeutic benefits. Some psychiatrists don’t bother with any of this and still give all their patients the same-sized electric shock. Some compromise and, rather than measuring a patient’s seizure threshold by dose titration (a trial and error method where patients are given electric shocks of increasing size until a seizure is produced), they just estimate a seizure threshold based on age and sex (young people and women tend to have lower seizure thresholds).
Although the psychiatric profession seems to be pretty much in agreement that a seizure is necessary for ECT to be effective, and that the electricity contributes to memory loss, there are apparently those who disagree. William T. Regenold, associate professor of psychiatry at the University of Maryland in the US, is currently doing an experiment using nonconvulsive electrotherapy on people. Here he explains:
“The aim of ECT is to induce a seizure, which is thought to be responsible for both its therapeutic and its adverse cognitive effects. The proposed modification consists of reducing the ECT electrical stimulus dose below the amount necessary to induce seizures so that adverse cognitive effects, such as confusion and memory problems, are minimized.”
Dr Regenold believes that it is the electric shock that is therapeutic, with the seizure being unnecessary and causing the memory problems.