The objective of this study is to investigate the antidepressant efficacy of rTMS, and to assess cortical metabolism before and after rTMS sessions in patients with major depression. We also aimed to investigate differences between the responders and nonresponders to rTMS and what would predict clinical response to rTMS.

The specific aims of this study is to: (1) evaluate the antidepressant efficacy of rTMS on major depression; (2) evaluate the effects of rTMS on cognitive function in depressive patients; (3) assess the effects of rTMS on cerebral glucose metabolism in depressive patients as measured by 18FDG PET; (4) investigate the differences of the regional cerebral glucose uptake changes during rTMS between responders and nonresponders to rTMS.

Inclusion Criteria:

• Twenty patients fulfilling the diagnostic criteria of major depression according to DSM IV will be enrolled in the study.
• Antidepressant medication will be maintained throughout the study period.

Exclusion Criteria:

• Exclusion criteria are current neurological or other psychiatric disorders, as well as a history of epileptic seizures, substantial brain damage or neurosurgical operation, according to established safety criteria.
• To exclude the effect of drug changes on post-rTMS cerebral glucose metabolism, the combinations and dosage of pre-rTMS antidepressant drugs will remain unchanged until the post-rTMS 18FDG PET is done.

Patients with major depressive disorder, who were not responsive to antidepressants