This study will assess an adjunctive treatment for major depressive disorder (MDD) called Aticaprant. Adults with MDD that are currently on an antidepressant but continue to experience prominent anhedonia may qualify.

This Study will assess whether 20 mg of seltorexant compared with placebo as adjunctive therapy to an SSRI/SNRI antidepressant improves depressive symptoms in participants with MDD and insomnia who have had an inadequate response to current SSRI/SNRI antidepressant therapy.

The aim of this study is to use magnetic resonance imaging (MRI) to capture images of participants' brains and apply an image processing method called INSCAPE to assess brain states. This study will recruit participants who are scheduled to receive accelerated Transcranial Magnetic Stimulation (TMS) therapy for Major Depressive Disorder (MDD). Participation in this study involves two visits, each including a 30-minute MRI scan. The interval between each visit is about one week. Depressed participants will also complete mood assessments at various intervals while they are receiving accelerated TMS for depression.

This is an inpatient clinical trial of a new form of transcranial magnetic stimulation with 10 treatments/day for 5 days, called SAINT. It is jointly funded by the NIH and a TMS company, MAGNUS. It is being done at 5 enrolling sites in the US, with total sampe of 100. Depressed and suicidal inpatients will have an MRI scan, then 5 days of treatment, and then a followup MRI scan. Outcome measures are depression and suicide ratings, as well as MRI changes. It is randomized and double blind, so some patients will not be getting active TMS. Importantly this is an adjunctive treatment study on top of all routine clinical treatments.