PatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.
Electroconvulsive therapy (ECT) has been around since the 1930s. It was originally tried in schizophrenia but it was soon shown to benefit patients with mood disorders. It was originally used without either anaesthesia or muscle relaxants and patients experienced significant injury.
ECT has stimulated mixed opinions both amongst the lay population and the medical profession. Some groups think it is harmful and invades patient autonomy and others feel that it is useful when performed under appropriate circumstances and if the risks and benefits are weighed.
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- Electrodes are placed on the skull. They can be placed on one side (unilateral ECT - usually on the non-dominant hemisphere) or both sides (bilateral ECT).
- Patients are given a general anaesthetic and a muscle relaxant.
- Subsequently, an electrical current is delivered to induce a generalised seizure.
- The patient has about 6-12 sessions, approximately twice a week. If the patient responds, then sessions are stopped. Rarely, ECT is used in maintenance therapy, about once a month.
Method of action
It is unclear how ECT works. However, it is hypothesised that it leads to increased release of neurotransmitters or enhances the response of postsynaptic receptors to brain chemicals.
The National Institute for Health and Care Excellence (NICE) recommends ECT for rapid improvement, in the short term, of symptoms in the following:
- Severe depressive illness or refractory depression.
- A prolonged or severe episode of mania.
It should only be used if other treatment options have failed or the condition is potentially life-threatening (eg, personal distress, social impairment or high suicide risk).
- ECT is usually only used in the short term and long-term benefits have not been documented. ECT should stop once a response is achieved or if the patient develops side-effects. Also, if the patient refuses further treatments then ECT should stop.
- Note that ECT is not useful in schizophrenia as the evidence is conflicting.
- Furthermore, the cost-effectiveness of ECT has not been decided.
Decisions to use electroconvulsive therapy
- Decisions to use ECT should only be made by mental health specialists.
- Decisions are based on weighing up the risks and benefits to the patient.
- Risk analysis includes the risk of the anaesthetic, risk of having no treatment and side-effects.
- Elderly patients and children are at increased risk.
- Pregnant women are at an increased risk.
- Decisions should be made in partnership with the patient if possible. The patient must give their consent if they have the capacity to do so.
- If patients are unable to give their consent then the decision will need to be made in the patient's best interests - it may be helpful to involve family and carers for advice.
- ECT in catatonia:
- Catatonia is associated with an alteration in muscle tone which can lead to the absence of movement or excessive movement.
- It is seen in schizophrenia and mood disorders.
- It is usually treated with benzodiazepines but, occasionally, patients require ECT. However, the benefit with ECT in catatonia has not been clearly evaluated and most evidence is based on case reports.
- ECT in mania:
- During a manic episode patients have an elevated mood and increased energy. During a severe episode patients are potentially dangerous to themselves and possibly to others.
- ECT is occasionally used, although antipsychotics are the mainstay of treatment. The evidence for the effectiveness of ECT is unclear.
- ECT in depression:
- ECT is used in severe depressive episodes - eg, depression with delusions and hallucinations. It may also need to be considered if patients become suicidal or homicidal.
- A systematic review and meta-analysis confirmed that ECT is effective in depression in the short term. Furthermore, ECT may be more effective than drug therapy in depression.
What is the evidence for the use of electroconvulsive therapy?
Real ECT has been compared with sham ECT. These trials have shown that ECT is more effective in the short term. Also, bilateral treatments are more effective than unilateral. These results have been seen in conditions such as depressive illness and mania.
On the other hand, a review of trials of schizophrenia and ECT has revealed that there is no clear benefit. Also, there have not been any comparisons between ECT and established antipsychotics - eg, clozapine. Further research is required and needs to include long-term effects, safety and role in certain groups - eg, elderly patients.
- Cardiovascular instability - eg, arrhythmias and hypotension.
- Status epilepticus.
- Related to the general anaesthetic.
- Peripheral nerve palsies.
ECT is associated with long-term and short-term memory deficits:
- This can affect anterograde and retrograde memory.
- The deficit is greater if the patient receives bilateral rather than unilateral ECT. It is also more apparent with unilateral ECT when electrodes are placed on the dominant side of the brain.
- Memory changes are more marked with an increasing number of treatments and the type of stimulus delivered.
- Changes in memory from ECT can be severe and very distressing for the patient. This can counteract any intended benefits.
- The cause of memory deficit is not known and brain imaging is normal. Some argue that the memory impairment is due to the underlying psychiatric condition rather than the ECT.
Mortality from ECT is not more than mortality from a general anaesthetic when undergoing minor surgery.
Further reading & references
- Guidance on the use of electroconvulsive therapy; NICE, April 2003
- Tharyan P, Adams CE; Electroconvulsive therapy for schizophrenia.; Cochrane Database Syst Rev. 2005 Apr 18;(2):CD000076.
- Greenhalgh J, Knight C, Hind D, et al; Clinical and cost-effectiveness of electroconvulsive therapy for depressive illness, schizophrenia, catatonia and mania: systematic reviews and economic modelling studies.; Health Technol Assess. 2005 Mar;9(9):1-156, iii-iv.
- Torrance R; Informed consent and ECT: how much information should be provided? J Med Ethics. 2014 Jun 17. pii: medethics-2013-101885. doi: 10.1136/medethics-2013-101885.
- Beloucif S; Informed consent for special procedures: electroconvulsive therapy and psychosurgery. Curr Opin Anaesthesiol. 2013 Apr;26(2):182-5. doi: 10.1097/ACO.0b013e32835e7380.
- Vaidya NA, Mahableshwarkar AR, Shahid R; Continuation and maintenance ECT in treatment-resistant bipolar disorder.; J ECT. 2003 Mar;19(1):10-6.
- Lisanby SH; Electroconvulsive therapy for depression. N Engl J Med. 2007 Nov 8;357(19):1939-45.
- No authors listed; Efficacy and safety of electroconvulsive therapy in depressive disorders: a systematic review and meta-analysis.; Lancet. 2003 Mar 8;361(9360):799-808.
- Pagnin D, de Queiroz V, Pini S, et al; Efficacy of ECT in depression: a meta-analytic review.; J ECT. 2004 Mar;20(1):13-20.
- Fink M, Taylor MA; Electroconvulsive therapy: evidence and challenges. JAMA. 2007 Jul 18;298(3):330-2.
- Van der Wurff FB, Stek ML, Hoogendijk WL, et al; Electroconvulsive therapy for the depressed elderly.; Cochrane Database Syst Rev. 2003;(2):CD003593.
- Donahue AB; Electroconvulsive therapy and memory loss. JAMA. 2007 Oct 24;298(16):1862.
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Dr Gurvinder Rull
Dr Roger Henderson
Dr John Cox