Lumateperone for Late-Life Depression

The purpose of this research study is to examine how well a medication called lumateperone (Caplyta) works to relieve depression in older adults with treatment-resistant depression. Lumateperone (Caplyta) is approved by the U.S. Food and Drug Administration to treat Major Depressive Disorder in adults who are also taking another antidepressant medication. This study will compare lumateperone (Caplyta) to placebo (a sugar pill without medication).

Inclusion Criteria: * Age \>=60 * Current unipolar non-psychotic major depression determined by SCID-5 * MADRS score \>=20 at screening and \>=18 at baseline * Treatment-resistance defined as documented history of non-response to at least two oral medications of adequate dose and duration in this episode or previous episode, OR clinician determination that treatment augmentation is appropriate * Currently taking oral antidepressant prescribed at least minimum therapeutic dose and for at least six weeks duration * MMSE score of \>/=24 Exclusion Criteria: * Dementia * High risk for suicide, defined as a 4 or 5 on C-SSRS (indicating active suicidal ideation with current or recent intent or plan), and unable to be managed safely in the clinical trial. Urgent psychiatric referral will be made in these cases. * High risk alcohol use: defined as a score of 6 or more on the AUDIT-C * Medically inappropriate for participation as determined by PIs.