Acute Response to ECT Linked to Lower Readmission Risk in South Korean Cohort

Electroconvulsive therapy remains one of the most effective yet debated treatments in psychiatry, but most long-term outcome data come from Western cohorts dominated by patients with major depressive disorder. A new retrospective cohort study from a tertiary referral center in South Korea now offers a transdiagnostic view, tracking how patients with depression, bipolar disorder, and schizophrenia fare after an acute course of ECT, both during hospitalization and after discharge.

The researchers followed 135 patients aged 16 and older who initiated an acute-phase ECT course between 2023 and 2025: 75 with major depressive disorder, 25 with bipolar affective disorder, and 35 with schizophrenia. These were refractory, heavily medicated patients, the kind of population in which diagnosis-specific long-term outcomes have been least well characterized. The team measured acute response and remission using the Clinical Global Impression-Severity scale and diagnosis-specific instruments, monitored cognition with the Montreal Cognitive Assessment, and tracked readmission-free survival over time.

The headline finding was that 59.3 percent of patients responded acutely to ECT, with a 95 percent confidence interval of 50.8 to 67.2 percent. But the response rate differed sharply by diagnosis, a difference that was statistically significant and persisted in sensitivity analyses. Patients with bipolar affective disorder responded at 84 percent, those with major depressive disorder at 61 percent, and those with schizophrenia at only 37 percent. Within each diagnostic group, symptom reductions were large, with Cohen’s d values ranging from 1.7 to 2.8, and cognition remained stable at the group level.

Over a median follow-up of 175 days, 37 patients, or 27 percent of the cohort, were readmitted to psychiatric care. Statistical models using Cox regression, which included acute response and maintenance ECT as a time-dependent covariate, showed that acute responders had roughly half the hazard of readmission compared with non-responders, with an adjusted hazard ratio of 0.49 and a confidence interval of 0.24 to 1.01. This suggests that how well a patient improves during the acute treatment phase carries real prognostic weight for the months that follow.

The diagnosis-specific picture after discharge was more nuanced. After adjustment for acute response, maintenance ECT, age, and sex, patients with bipolar disorder had a higher estimated readmission hazard than those with depression, with an adjusted hazard ratio of 2.11, though the confidence interval of 0.89 to 5.00 crossed one, meaning the association was not statistically significant. Patients with schizophrenia showed a readmission hazard similar to those with depression, at an adjusted hazard ratio of 1.04. Between-group differences in readmission-free survival overall were not significant, with a log-rank p value of 0.248.

Maintenance ECT, a continuation strategy designed to consolidate gains after the acute course, was transitioned to by different proportions of each group. It was least frequent among patients with bipolar disorder, at 28 percent, compared with 54 percent in the schizophrenia group, a difference that approached but did not reach statistical significance with a p value of 0.083. Across the cohort, moving to maintenance ECT was associated with a nonsignificantly lower readmission hazard, at an adjusted hazard ratio of 0.55 with a confidence interval of 0.25 to 1.22.

The authors’ central conclusion is cautious: acute improvement alone may not ensure durable stability in patients with bipolar affective disorder, even though this group showed the strongest acute response. The combination of high initial response and a higher estimated postdischarge hazard, after accounting for that response, points to a gap between short-term efficacy and long-term relapse prevention that deserves targeted attention.

As with any retrospective single-center study, the findings come with limitations. The sample sizes within diagnostic subgroups were modest, several key associations had confidence intervals that included the null value, and the follow-up window of roughly six months at median captures early rather than long-term outcomes. The researchers call for prospective evaluation of relapse-prevention strategies, particularly in patients with bipolar disorder, to determine whether structured continuation treatment can convert strong acute responses into lasting stability outside the hospital.

Subject of Research: Acute ECT response and psychiatric readmission outcomes across depression, bipolar disorder, and schizophrenia in a South Korean retrospective cohort

Article Title: Transdiagnostic trajectories of acute response and readmission after electroconvulsive therapy: a retrospective cohort study in South Korea

Article References: Oh, S., Yeom, C.-W., Hong, M., Seo, M., Shin, J., Lee, J., Kim, Y. S., & Joo, E. J. (2026). Transdiagnostic trajectories of acute response and readmission after electroconvulsive therapy: a retrospective cohort study in South Korea. BMC Psychiatry. https://doi.org/10.1186/s12888-026-08763-x

Image Credits: AI Generated

DOI: 10.1186/s12888-026-08763-x

Keywords: electroconvulsive therapy, bipolar disorder, major depressive disorder, schizophrenia, readmission, maintenance ECT, retrospective cohort, South Korea, psychiatry, acute response, relapse prevention, Transdiagnostic