Selegiline remarkably improved stage 5 treatment-resistant major depressive disorder: a case report

Yuji Kitaichi,¹ Takeshi Inoue,¹ Nobuyuki Mitsui,¹ Shin Nakagawa,¹ Rie Kameyama,¹ Yoshiyuki Hayashishita,¹ Tohru Shiga,² Ichiro Kusumi,¹ Tsukasa Koyama<sup>1

1</sup>Department of Psychiatry, Graduate School of Medicine, Hokkaido University, Sapporo, Japan; ²Department of Nuclear Medicine, Graduate School of Medicine, Hokkaido University, Sapporo, Japan

Abstract: We report a case in which selegiline, an irreversible monoamine oxidase B (MAO-B) inhibitor, greatly improved depressive symptoms in an adult with stage 5 treatment-resistant major depressive disorder. Four antidepressants and four augmentation therapies had previously been ineffective or intolerable, and electroconvulsive therapy had only a temporary effect. After 20 weeks of treatment with selegiline (10 mg/day), the patient's score on the 17-item Hamilton Depression Rating Scale (HDRS) had decreased from 19 to 4 points. [¹⁸F]-Fluorodeoxyglucose positron emission tomography (FDG-PET) showed increased glucose metabolism in the bilateral basal ganglia after initiating selegiline treatment; blood dopamine levels were also increased after selegiline treatment. These results raise the possibility that selegiline enhances dopaminergic neural transmission in treatment-resistant depression, thus leading to an improvement in depressive symptoms.

Keywords: treatment-resistant depression, FDG-PET, glucose metabolism, basal ganglia