3 The technology
3.1 During ECT, an electric current is passed briefly through the brain, via electrodes applied to the scalp, to induce generalised seizure activity. The individual receiving treatment is placed under general anaesthetic and muscle relaxants are given to prevent body spasms. The ECT electrodes can be placed on both sides of the head (bilateral placement) or on one side of the head (unilateral placement). Unilateral placement is usually to the non-dominant side of the brain, with the aim of reducing cognitive side effects. The amount of current required to induce a seizure (the seizure threshold) can vary up to 40 fold between individuals.
3.2 Although ECT has been used since the 1930s, there is still no generally accepted theory that explains its mechanism of action. The most prevalent hypothesis is that it causes an alteration in the post-synaptic response to central nervous system neurotransmitters.
3.3 In recent years, there have been moves to improve standards in the administration of ECT, with the introduction of practice guidelines published by the Royal College of Psychiatrists and the Royal College of Nursing, and the monitoring of the implementation of these guidelines through ongoing audit. However, there is still variation in the use and practice of ECT within England and Wales.
3.4 ECT administration affects the central nervous system and causes changes in cardiovascular dynamics, which dictates the need for special caution in those individuals who are at increased risk of a cardiovascular event. There are also other immediate potential complications, such as status epilepticus, laryngospasm and peripheral nerve palsy, which overall have an estimated incidence of 1 per 1300 to 1400 treatments. The mortality associated with ECT is reported not to be in excess of that associated with the administration of a general anaesthetic for minor surgery.
3.5 ECT may cause short- or long-term memory impairment for past events (retrograde amnesia) and current events (anterograde amnesia). As this type of cognitive impairment is a feature of many mental health problems it may sometimes be difficult to differentiate the effects of ECT from those associated with the condition itself. In addition there are differences between individuals in the extent of memory loss secondary to ECT and their perception of the loss. However, this should not detract from the fact that a number of individuals find their memory loss extremely damaging and for them this negates any benefit from ECT.
3.6 Advance directives are statements made by an individual that express decisions about the healthcare they wish to receive, in anticipation of a time when they may not be competent to make or communicate such decisions. Clinicians are legally obliged to take informed and unambiguous advance refusals of treatment made by a competent individual into account unless: (1) it does not apply to the circumstances that have arisen; (2) the Mental Health Act is used to override the individual's intentions about treatment; (3) it requires the clinician to do something illegal; or (4) it requires treatment that the clinician considers not to be in the individual's best interests. Advance consents are not legally binding because specific medical treatment cannot be demanded, but clinicians should generally take such wishes into account.
3.7 The number of sessions undertaken during a course of ECT usually ranges from 6 to 12, although a substantial minority of patients respond to fewer than 6 sessions. ECT is usually given twice a week; less commonly it is given once a fortnight or once a month as continuation or maintenance therapy to prevent the relapse of symptoms. It can be given on either an inpatient or day patient basis. In England between January and March 1999, there were 16,482 administrations of ECT to 2835 individuals, 41% of whom were aged 65 years or over. Seventy-five per cent of the individuals were not formally detained under the Mental Health Act 1983, and of the 709 individuals formally detained, 59% did not or were not able to consent to treatment.
3.8 Six treatment sessions of ECT have been estimated to cost £2475. This does not include inpatient costs, estimated as £171 per day.