Maintaining remission after electroconvulsive therapy (ECT) is of clinical relevance in patients with depression, and maintenance ECT is introduced in patients who fail to maintain remission after ECT. However, the clinical characteristics and the biological background of patients who receive maintenance ECT are barely understood.

At Keio University Hospital, Patients with major depressive disorder according to DSM-IV who received ECT between January 2012 and March 2019 followed by maintenance ECT (mECT group) and those who did not (aECT group) were included. Clinical characteristics including the results of neuroimaging marker for Parkinson’s disease and dementia with Lewy bodies were compared between groups.

Thirteen and one hundred forty-six patients were included in mECT and aECT groups, respectively. Compared with aECT group, the age of onset and the age of the first ECT was older in mECT group. Besides, mECT group showed significantly higher prevalence of melancholic feature (92.3% vs. 27.4%, p<0.001) and catatonic feature (46.2% vs. 9.6%, p=0.002). The results of neuroimaging marker obtained in 123I-metaiodobenzylguanidine scintigraphy and dopamine transporter scan revealed that 5 of 13 patients and 16 of 146 patients showed Parkinson’s disease and dementia with Lewy bodies in mECT and aECT groups, respectively.

Patients who underwent acute and maintenance ECT have impaired dopamine function. Investigating the neurobiology of patients who receiving maintenance ECT is an important area for development of appropriate treatment for depression.