Investigate the effects of pretreatment using a single, sub-anesthetic dose of intranasal ketamine on the response to a standard course of rTMS in patients who meet the definition of TRD.
An open label study to assess the safety, tolerability, and effects of intranasal Ketamine in combination with rTMS for patients with treatment-resistant major depressive disorder (TRD). Patients will be given a dose of ketamine followed by 6 weeks of rTMS treatment.