When should the course of ECT finish?
The aim of ECT should be remission of symptoms with a minimum of side-effects. Remission rates for those with severe, usually treatmentresistant depression are approximately 60–80% (Husain et al, 2004; Eranti et al, 2007). In a multicentre US study of thrice-weekly bitemporal ECT (n=253), a 30% decrease in symptoms after six treatments was found to predict final remission (Fig. 4.1) (Husain et al, 2004). The majority of these remissions occurred before the ninth treatment. However, 40% of patients who had not responded after six treatments went on to remission. So no definitive recommendation can be given to stop treatment in those who have failed to respond after six treatments. However, if after six satisfactory treatments there has been no clinical response whatsoever, clinicians may wish to reassess the need for ECT and consult with the patient, based on the decreased predicted response and remission rate for subsequent treatment (e.g. 40% v. 70% in the above study). If patients are failing to respond or are responding slowly, ECT teams should liaise further with referring clinicians regarding ECT dosing, medications, side-effects and any other reasons for modifying or stopping the treatment course. A patient who has had no response within 12 treatments is unlikely to have a sustained response to ECT.
How often should ECT be prescribed?
In addition to electrode placement, stimulus intensity and waveform (discussed later), the effectiveness of ECT is influenced by frequency of administration. Electroconvulsive therapy is usually given twice weekly in the UK, Ireland and several other European countries, whereas in the USA, thrice-weekly treatment is common practice. The UK ECT Review Group (2003) meta-analysis failed to find statistically significant differences between twice- and thrice-weekly bitemporal ECT with a fixed number of treatments (Kellner et al, 1992; Gangadhar et al, 1993; Lerer et al, 1995; Janakiramaiah et al, 1998; Shapira et al, 1998; Vieweg, 1998; UK ECT Review Group, 2003). There were trends showing thrice-weekly ECT to be no more effective than twice-weekly treatment but to have more cognitive side-effects. The clinical and cognitive outcomes of clinical trials in which patients are treated thrice weekly may not be fully applicable to routine UK practice.
One open study suggested that unilateral ECT delivered more often could be as effective as bitemporal ECT given twice weekly (Stromgren, 1975; Stromgren et al, 1976).