Augmentation of clozapine with ECT: a retrospective case analysis

Lally, John; Breese, Emily; Osman, Mugtaba; Hua Sim, Cai; Shetty, Hitesh; Krivoy, Amir and MacCabe, James H (2021). Augmentation of clozapine with ECT: a retrospective case analysis. Acta neuropsychiatrica, 33(1) pp. 31–36.



We sought to assess the effectiveness of clozapine augmentation with ECT (C+ECT) in patients with clozapine-resistant schizophrenia.

We conducted a retrospective review of electronic health records to identify patients treated with C+ECT. We determined the response to C+ECT and the rate of rehospitalisation over the year following treatment with C+ECT.

Forty-two patients were treated with C+ECT over a ten year period. The mean age of the patients at initiation of ECT was 46.3 (SD=8.2) years (range 27-62 years). The mean number of ECTs given was 10.6(SD = 5.3)(Range 3-25) with the majority receiving twice weekly ECT. Seventy six percent of patients (n=32) showed a Clinical Global Impression improvement score (CGI-I) of≤3 (at least minimally improved) following C+ECT. The mean number of ECT treatments was 10.6 (SD = 5.3) (range 3-25) with the majority receiving twice weekly ECT. Sixty four percent of patients experienced no adverse events. Response to C+ECT was not associated with gender, age, duration of illness, or duration of clozapine treatment.Seventy five percent of responders remained out of hospital over the course of one-year follow up, while 70% of those with no response to C+ECT were not admitted to hospital. Three patients received maintenance ECT, one of whom was rehospitalised.

This study lends support to emerging evidence for the effectiveness of C+ECT in clozapine resistant schizophrenia. These results are consistent with the results of a meta-analysis and the only randomised controlled trial (RCT) of this intervention. Further RCTs are required before this treatment can be confidently recommended.

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