Schizophrenia is a severe mental illness and a common indication for electroconvulsive therapy (ECT). Research is lacking on the factors that influence response to acute ECT treatment in schizophrenia patients.

This study examined the response rate and associated factors in patients with schizophrenia undergoing bilateral ECT.

Demographic data, clinical characteristics, ECT data and treatment response were respectively reviewed in patients with schizophrenia undergoing bilateral ECT from January 2013 to June 2022.

Forty-six patients were included. Nine responded after the first three sessions, 17 after six sessions, 20 after nine sessions, 25 after 12 sessions and 28 after the last ECT session, cumulatively. The mean of the baseline Brief Psychiatric Rating Scale psychotic symptom subscale score was significantly higher in responders (17.0) than non-responders (10.9) (P < 0.05). The mean of duration of electroencephalogram seizure was significantly longer in responders (53.9) than in non-responders (42.7). There was no association between demographic and ECT data and treatment response. Among 28 responders, 20 responded to ECT after nine sessions (faster responders) and eight responded later (slower responders). The number of failed antipsychotics prior to ECT was 2.8 for faster responders and 4.4 for slower responders (P = 0.02). Nominal logistic regression showed that the number of failed antipsychotics prior to ECT was associated with speed of response to ECT (P = 0.037, odds ratio = 1.77).

ECT is an effective treatment for schizophrenia and may be influenced by the number of failed antipsychotics prior to ECT.