Study PI left institution and there is currently no one else available to run the study.

The Investigators are proposing to demonstrate safety and efficacy of LIFUP for treatment resistant major depressive disorder in a ten-patient pilot study. LIFUP is an emerging treatment with the advantage of being able to target subcortical transcranial targets, which may have superior efficacy or a shorter treatment course compared to other available treatments such as transcranial magnetic stimulation. This study will investigate the effect of this stimulation on the left subgenual cingulate cortex, a highly connected node in the depression network that is correlated with clinical symptomatology.

The purpose of this pilot study is to evaluate safety and efficacy of a novel treatment, low intensity focused ultrasound pulsation (LIFUP) for treatment resistant depression (TRD). Participants will receive either LIFUP or sham stimulation with crossover of sham participants into the treatment group halfway through the treatment course. The initial visit will involve consent and an MRI scan, followed by several more either active or sham treatments outside of the MRI environment delivered over the course of two days over one week. Response and potential side effects will be monitored pre- and post- each treatment along with one week and one month follow-up assessments.

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.