Shock Treatment for Depression: Insight into a Contentious Treatment

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What is Shock Treatment?

Shock treatment, better known as electroconvulsive therapy or ECT, is administered under medical conditions. Once the patient has been fully sedated they are given a muscle relaxant. ECT is administered by placing electrodes (pads) on either one or both sides of the head. Electrodes placed on either side of the head (bilateral ECT) produce a seizure affecting the whole of the brain. Electrodes placed to one side of the head (unilateral ECT) produce a seizure in that hemisphere. Sufficient electrical current is then sent into the brain to cause the patient to convulse (fit). The complete procedure, including preparations, anesthesia and recovery takes roughly 30 minutes and sometimes less. The actual seizure lasts for a few seconds.

A typical course of shock treatment for depression averages 6-9 sessions spaced two or three times a week, but the dose and timing can be varied in order to optimize treatment effects and/or reduce side effects. Progress is always monitored however and if the required therapeutic effects are seen earlier the treatments may well be stopped.

How Does ECT Work?

There is continuing controversy over the use of ECT, partly because little is known about how it actually works, despite a range of theories. It remains in use however precisely because it achieves a therapeutic effect where drugs and other forms of therapy cannot. There is some debate over the relative merits of unilateral over bilateral stimulation. Bilateral ECT appears to work more quickly and effectively but has a higher risk of side effects.

When is ECT Prescribed?

Strict guidelines are now in place over the use of ECT. The patient must be severely depressed and/or suicidal and be unresponsive to drug therapies, or suffer severe side effects from drugs normally prescribed for depression. Because antidepressant medication is known to take several weeks before a therapeutic effect is seen, they may not be an option for people who express suicidal thoughts. In very severe cases of depression the person becomes almost entirely apathetic, to the point where they neither eat nor drink. Response to physical pain is also dulled so there is a danger of severe injuries not being acknowledged or treated. In such cases time is a critical factor and the prospect of waiting several weeks in the hopes that antidepressants might work is simply not viable. By contrast, ECT is known to have fairly rapid therapeutic effects and for this reason it may be strongly recommended.

ECT may also be prescribed if it has previously been used to good effect. It is a consent-based treatment and cannot normally be administered if the patient refuses their consent. In very exceptional circumstances, for example where a treatment order has been enforced and there is genuine concern over the welfare of the patient, ECT may be administered without consent. Regulations over the enforced use of ECT may vary between countries or states.

What are the Therapeutic Effects of ECT?

Shock treatment for depression in the form of ECT is a proven and effective form of therapy. Carney et al (2003) conducted a meta analysis of 18 controlled trials and concluded that ECT is significantly more effective than both placebo and antidepressants. The main problem with ECT is that its therapeutic effects tend to be short term. The relapse rate is quite high and one study (Sackeim et al., 2001) found nearly all remitted patients relapsed within a six month period if they did not continue with antidepressant medication.

ECT is also an option for new mothers suffering from severe depression. It is also effective in cases of severe mania that do not respond to medication.

What are the Side Effects of ECT?

A continuing concern over the use of ECT is its potentially damaging side effects. Immediately following ECT patients may complain of headache, nausea, fuzziness, muscle aches and fatigue. These symptoms pass fairly quickly. Because ECT often causes a rise in blood pressure it is not prescribed for patients known to have an aneurysm, but this is mainly due to the chances of an aneurysm bursting during muscular cramping.

The most frequently reported long-term side effect is retrograde amnesia, that is, loss of memory for events going back months or sometimes years. Amnesia generally improves in the months following treatment but for events immediately preceding ECT it often remains (Coleman et al, 1996). Despite fears over possible structural damage to the brain no evidence exists to this effect.


Carney, S., Cowen, P., Geddes, J., et al (2003). Efficacy and safety of electroconvulsive therapy in depressive disorders: a systematic review and meta-analysis. Lancet, 361, 799-808.

Coleman, E.A., Sackeim, H.A., Prudic, J., et al (1996) Subjective memory complaints prior to and following electroconvulsive therapy. Biological Psychiatry, 39, 346-356.

Sackeim, H.A., Haskett, R.F., Mulsant, B.H., et al (2001) Continuation pharmacotherapy in the prevention of relapse following electroconvulsive therapy: a randomized controlled trial. Journal of the American Medical Association, 258, 1299-1307.