Electroconvulsive therapy for schizophrenia

Abstract

Background: Electroconvulsive therapy (ECT) involves the induction of a seizure (fit) for therapeutic purposes by the administration of a variable frequency electrical stimulus shock via electrodes applied to the scalp. The effects of its use in people with schizophrenia are unclear.

Objectives: To determine whether electroconvulsive therapy (ECT) results in clinically meaningful benefit with regard to global improvement, hospitalisation, changes in mental state, behaviour and functioning for people with schizophrenia, and whether variations in the practical administration of ECT influences outcome.

Search strategy: Electronic searches of Biological Abstracts (1982-1996), EMBASE (1980-1996), MEDLINE (1966-2001), PsycLIT (1974-1996),SCISEARCH (1996) and the Cochrane Schizophrenia Group's Register (July 2001) were undertaken. The references of all identified studies were also inspected and authors contacted.

Selection criteria: All randomised controlled clinical trials that compared ECT with placebo, 'sham ECT', non-pharmacological interventions and antipsychotics, and different schedules and methods of administration of ECT for people with schizophrenia, schizoaffective disorder or chronic mental disorder.

Data collection and analysis: Studies were reliably selected, quality rated and data extracted. For dichotomous data, relative risks (RR) were estimated, with the 95% confidence intervals (CI). Where possible, the number needed to treat statistic (NNT) was calculated. Analysis was by intention-to-treat. Normal continuous data was summated using the weighted mean difference (WMD). Scale data was presented for only those tools that had attained pre-specified levels of quality. Tests of heterogeneity and for publication bias were undertaken.

Main results: This review includes 24 trials with 46 reports. When ECT is compared with placebo or sham ECT, fewer people remain unimproved in the real ECT group (n=400, RR fixed 'not globally improved in the short term' 0.77 CI 0.6 to 0.9, chi-square 13.46 df=8 p=0.1). Removal of the one study with clearly heterogeneous results causes a change in the findings (n=380, 8 RCTs, RR fixed 0.83 CI 0.7 to 1.01), as does removal of a clinically heterogeneous trial (n=370, 8 RCTs, RR fixed 0.74 CI 0.6 to 0.9, chi-square 10.97 df=7 p=0.14). There was a suggestion that ECT resulted in less relapses than sham ECT (n=47, 2 RCTs, RR fixed 0.26 CI 0.03 to 2.2), and a greater likelihood of being discharged from hospital (n=98, 1 RCT, RR fixed 0.59, CI 0.34 to 1.01). There is no evidence that this early advantage for ECT is maintained over the medium to long term. People treated with ECT did not drop out of treatment earlier than those treated with sham ECT (n=495, 14 RCTs, RR fixed 0.71 CI 0.33 to 1.52). Very limited data indicated that visual memory might decline after ECT compared with sham ECT (n=24, 1 RCT, WMD -14.0 CI -23 to -5); the results of verbal memory tests were equivocal. When ECT is directly compared with antipsychotic drug treatment (total n=419, 8 RCTs), results favour the medication group (n=175, 3 RCTs, RR fixed 'not improved at the end of ECT course' 2.18 CI 1.3 to 3.6). One small study suggested more memory impairment after a course of ECT combined with antipsychotics than with antipsychotics alone (n=20, MD serial numbers and picture recall -4.90 CI -0. 8 to -9), though this proved transient. When continuation ECT was added to antipsychotic drugs, the combination was superior to the use of antipsychotics alone (n=30, WMD Global Assessment of Functioning 19.1 CI 9.7 to 28.5), or CECT alone (n=30, WMD -20.3 CI -11.5 to -29.1). Unilateral and bilateral ECT were equally effective in terms of global improvement (n=78, 2 RCTs, RR fixed 'not improved at end of course of ECT' 0.79 CI 0.5 to 1.4). One trial showed a significant advantage for 20 treatments over 12 treatments for numbers globally improved at the end of the ECT course (n=43, RR fixed 2.53 CI 1.1 to 5.7).

Reviewer's conclusions: There is no evidence to clearly refute the use of ECT for people with schizophrenia. There is some limited evidence to support its use, particularly combined with antipsychotic drugs for those with schizophrenia who show limited response to medication alone. The research base for the use of ECT in people with schizophrenia is growing but, even after more than five decades of clinical use, is still inadequate.