Clozapine is one of the most effective drugs for the treatment resistant schizophrenia (TRS). It was reported that modified electroconvulsive therapy (mECT) may be an effective clozapine augmentation strategy in TRS.

The objective of this study was to investigate the influence of clozapine to mECT in the TRS.

Forty-seven patients were recruited in this study, but eight patients were excluded because clozapine was discontinued by reason of side effects. Ultimately, 39 patients were enrolled.

Seventeen patients received mECT before clozapine therapy. Two patients continued mECT after starting clozapine therapy. There was a significant difference between before–after clozapine therapy (χ2 test, P< 0.01). Intermittent mECT was performed for 3 patients before clozapine and for one patient after starting clozapine.

This result suggests that clozapine therapy reduces mECT. In Japan, the first-line treatment for TRS is CLO. mECT is recommended for clozapine resistant schizophrenia patients. Prescription of CLO is limited in the part of medical facility because all physicians who prescribe clozapine must be registered with the clozaril patient monitoring service in Japan. It is considered that mECT is more readily selected than clozapine therapy. Therefore, the number of mECT is not reduced generally.

Clozapine therapy reduces the necessity of mECT.

The authors have not supplied their declaration of competing interest.