Suvorexant for Alcohol Use Disorder (AUD): Neural Mechanisms

* INCLUSION CRITERIA: * All Participants To be eligible to participate in this study, an individual must meet all of the following criteria: * Stated willingness to comply with all study procedures and availability for the duration of the study. * Male or female, ages 18-75 years old. * Ability to understand and the willingness to sign a written informed consent document. * AUD Participants To be eligible to participate in this study, an individual with AUD must meet all of the "All Participants" inclusion criteria (listed above) and also meet the following criteria: * DSM 5 diagnosis of moderate or severe AUD. * Participants seeking treatment for their AUD. * Current AUD with minimum 5-year lifetime history of heavy drinking (SAMSHA's criteria for heavy drinking: for men 5 or more drinks/day on at least 5 different days per month; and for women 4 or more drinks/day on at least 5 different days per month). * Last alcohol use within the 7 days prior to enrollment in the Natural History protocol 14AA0181. * Self-reported insomnia/sleep problems: PSQI score \> 4 and/or endorsing "problems falling asleep or staying asleep throughout the night". * Ability to take oral medication and be willing to adhere to the suvorexant/placebo regimen. * Agreement to commit to at least 28 days, and up to 40 days, inpatient stay (starting from Natural History protocol enrollment). * Agreement to adhere to Lifestyle Considerations throughout study duration. EXCLUSION CRITERIA: -All Participants An individual who meets any of the following criteria will be excluded from participation: * Presence of ferromagnetic objects in the body that are contraindicated for MRI of the head, fear of enclosed spaces, or other standard contraindication to MRI. * Cannot lie comfortably flat on his/her back for up to 2 hours in the MRI scanner. * Body weight \> 400 lbs. The PET scanner bed is tested to a weight limit of 400 lbs. * Have had previous radiation exposure (from X-rays, PET scans, or other exposure) that, with the exposure from this study, would exceed NIH annual research limits as determined by medical history and physical exam. * Pregnant or breast-feeding: Females of childbearing potential, or with tubal ligation, or are post-menopausal and are age 55 or less will undergo a urine pregnancy test and it must be negative to continue participation. Urine pregnancy tests will be repeated on subsequent days of study involving imaging scans (i.e., within 24 hours before study procedures). Females must not be currently breastfeeding. * Severe head trauma with loss of consciousness \> 60 minutes. * Chronic recurrent primary psychotic disorders like schizophrenia and bipolar 1 disorder. * Montgomery-Asberg depression rating scale (MADRS) total score \> 35 or 'suicidal thoughts' item score \> 3, indicating severe depression or moderate suicidality, respectively. * Major medical problems that can permanently impact brain function (e.g., seizures, psychosis, stroke, Alzheimer's disease, Parkinson's disease, traumatic brain injury, clinically significant arrhythmias except bradycardia, and HIV+). * Hepatic enzymes (ALT/GPT, AST/GOT, Total Bilirubin, Direct Bilirubin) that are \>5x the upper limit of normal, indicating severe hepatic impairment. * Non-English speakers (must also be able to read and comprehend English). * The intent of the research has no prospect of direct benefit to the subject. Therefore, we are excluding non-English speakers in this research study since it includes the administration of questionnaires, surveys and assessments that are validated for English; only some are available in Spanish. In addition, our fMRI paradigms require that the subject be able to speak, read and comprehend English. -AUD Participants An individual with AUD who meets any of the "All Participants" exclusion criteria (listed above) or any of the following criteria will be excluded from participation in this study: * Current daily use of stimulant medications, modafinil, wellbutrin, naltrexone, antipsychotics, or strong CYP3A inhibitors (e.g., ketoconazole, itraconazole, posaconazole, clarithromycin, nefazodone, ritonavir, saquinavir, nelfinavir, indinavir, boceprevir, telaprevir, telithromycin and conivaptan). * Current benzodiazepine, opioids, or stimulant misuse (must have misused 5+ days/week for \>1 year, and most recent use must have been within 7 days of inpatient admission). * Current severe substance use disorders (other than alcohol, cannabis, nicotine or caffeine). If a subject had a severe SUD (other than alcohol, cannabis, nicotine or caffeine), they must be in remission for at least 6 months prior to enrollment. * Major medical problems that are contraindicated for the use of suvorexant (narcolepsy, severe obstructive sleep apnea or severe chronic obstructive pulmonary disease, REM behavioral disorder) as determined by history and clinical exam. Note that AUD subjects will not be excluded from enrollment onto this study if their urine test or breath alcohol level (BAL) is positive for drugs/alcohol on initial screening. The following guidelines will be followed for positive drug/alcohol screens on study procedure days involving imaging scans: -If a subject's urine drug/breath alcohol (\>=0.08%) screen test is positive on days involving imaging (MRI and/or PET), the procedures will be postponed until BrAC \<0.08. This is not expected to happen in most cases especially since participants will have been detoxifying for 1-5 days (possibly longer) and should no longer test positive for BrAC at this point. After initial screening under 14AA0181, subjects will be in the inpatient unit detoxifying. * If urine drug screen is positive for THC-COOH, a saliva drug screen will be performed. However, there are reports that THC can still be detected in saliva even eight days after cessation of drug use. Because of this, AUD subjects may proceed with study day testing procedures even if saliva results for