Low-Intensity Focused Ultrasound for Treatment-Resistant Depression

Inclusion criteria: Male or female Age 18-70 Normal or corrected-to normal vision and hearing Primary diagnosis of major depressive disorder, moderate/severe per DSM-5 (MADRS >20) The duration of the illness must exceed one year Must be medically stable as determined by investigator Patient must have attempted and failed treatment with at least 2 SSRI and 1 augmentation History of rTMS is permitted, but not required Exclusionary criteria: Diagnosis of primary DSM-5 depressive disorder other than MDD Anxiety disorders such as GAD are permitted as long as MDD is primary Diagnosis of schizophrenia or bipolar disorder Current use of any non-prescribed psychoactive medications or drugs (aside from medications for treatment of MDD) Contraindication to enter the MRI environment. Pregnancy (or suspected/possible pregnancy or plan to become pregnant in the short term). Urine Pregnancy Test: If the subject is a woman of childbearing potential and /or a man capable of fathering a child before, during, and/or after participation precaution should be taken. Examples of acceptable methods of birth control for participants involved in the study includes: birth control pills, patch, IUD, condom, sponge, diaphragm with spermicide, or avoiding sexual activity that could cause the subject to become pregnant. Inability to adhere to treatment schedule. Initiation of new antidepressant treatment at the time of study randomization.