Overview

The purpose of this study is to determine efficacy differences between ALTO-300 and placebo, used adjunctively to an antidepressant, related to patient characteristics.

Eligibility

Inclusion Criteria:

• Have a diagnosis of moderate to severe major depressive disorder (MDD)
• At Visit 2, currently taking a single SSRI, SNRI, or bupropion for at least 6 weeks with no dose modifications in the past 2 weeks
• Willing to comply with all study assessments and procedures
• Must not be pregnant or breastfeeding at time of enrollment or throughout study

Exclusion Criteria:

• Evidence of unstable medical condition
• Nightly use of sleep medication
• Diagnosed bipolar disorder, psychotic disorder, or dementia
• Current moderate or severe substance use disorder
• Has a history of hypersensitivity or allergic reaction to ALTO-300 or any of its components/excipients
• Concurrent or recent participation in another clinical trial for mental illness involving an investigational product or device