This study is for people with *Opioid Use Disorder (OUD)*, who have trouble sleeping. The researchers aim to see if a medicine called **suvorexant** can help them sleep better. Suvorexant is a medication commonly used to treat insomnia, which is when someone finds it hard to fall asleep or stay asleep. The study will compare suvorexant to a **placebo**. A placebo is a fake treatment that looks like the real medicine but doesn't contain any active ingredients.

**Key Points to Consider:**

• The study requires participants to have a regular bedtime between 8 PM and 1 AM and maintain it throughout the study.
• Participants must not have used opioids for at least 4 weeks prior to the study.
• Exclusion criteria include having certain mental health disorders or a history of serious sleep disorders.

If you have OUD, are on stable medication, and struggle with insomnia while meeting the criteria, this study might be an opportunity to try a new treatment for better sleep.