The primary purpose of this study is to assess the target occupancy at kappa and mu opioid receptors in the brain after single oral doses of CVL-354 in healthy adult participants.

Inclusion Criteria:

1. Women of nonchildbearing potential and men 18 to 55 years, inclusive, at the time of signing the informed consent form (ICF).

2. Healthy as determined by medical evaluation, including medical and psychiatric history, physical and neurological examinations, ECG, vital sign measurements, and laboratory test results, as evaluated by the investigator.

3. Body mass index of 18.5 to 32.0 kilograms per square meter (kg/m^2), inclusive, and total body weight >50 kg (110 pounds [lb]) at Screening.

4. Sexually active men with a pregnant or nonpregnant partner of childbearing potential must agree to comply with the following contraception requirements during the trial and for 7 days after the last dose of investigational medicinal product (IMP):

   • Use condom or remain abstinent. In addition, male participants should not donate sperm for a minimum of 7 days following the last dose of IMP.

5. Capable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the ICF and in this protocol.

6. Ability, in the opinion of the investigator, to understand the nature of the trial and comply with protocol requirements, including the prescribed dosage regimens, scheduled visits, laboratory tests, and other trial procedures.

Exclusion Criteria:

1. Current or past history of significant cardiovascular, pulmonary, gastrointestinal, renal, hepatic, metabolic, genitourinary, endocrine (including diabetes mellitus), malignancy (except for basal cell carcinoma of the skin and cervical carcinoma in situ, at the discretion of the investigator), hematological, immunological, neurological, or psychiatric disease that, in the opinion of the investigator or medical monitor, could compromise either participant safety or the results of the trial.

2. "Yes" responses for any of the following items on the C-SSRS (within the individual's lifetime):

   • Suicidal Ideation Item 3 (Active Suicidal Ideation with Any Methods [Not Plan] without Intent to Act)
   • Suicidal Ideation Item 4 (Active Suicidal Ideation with Some Intent to Act, without Specific Plan)
   • Suicidal Ideation Item 5 (Active Suicidal Ideation with Specific Plan and Intent)
   • Any of the Suicidal Behavior items (Actual Attempt, Interrupted Attempt, Aborted Attempt, Preparatory Acts or Behavior) "Yes" responses for any of the following items on the C-SSRS (within past 12 months):
   • Suicidal Ideation Item 1 (Wish to be Dead)
   • Suicidal Ideation Item 2 (Non-Specific Active Suicidal Thoughts) Serious risk of suicide in the opinion of the investigator is also exclusionary.

3. History of substance or alcohol-use disorder (excluding nicotine or caffeine) as per Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria within 12 months prior to signing the ICF.

4. Any condition or surgery that could possibly affect drug absorption, including, but not limited to, bowel resections, bariatric weight loss surgery/procedures, gastrectomy, uncomplicated appendectomy, and cholecystectomy.

5. Receipt of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination or booster within 7 days of planned dosing. In addition, participants who plan to receive SARS-CoV-2 vaccination or booster while participating in the trial or for a minimum of 7 days (to cover at least 5 half-lives of IMP) after the last dose of IMP will be excluded.

6. Have recently been diagnosed with symptomatic coronavirus disease-2019 (COVID-19) or test positive (i.e., using polymerase chain reaction (PCR) or rapid antigen test) for COVID-19 within 30 days prior to signing the ICF.

7. Use of prohibited medication prior to randomization or likely to require prohibited concomitant therapy (e.g., prescription and over-the-counter medications, herbal medications, vitamins, and supplements) during the trial.

8. Positive result for human immunodeficiency virus (HIV) antibody, hepatitis B surface antigen, hepatitis B core antibody, or hepatitis C antibody with detectable viral ribonucleic acid (RNA) levels at Screening.

9. Positive drug screen (including cotinine and tetrahydrocannabinol [THC]) or a positive test for alcohol.

10. Any of the following clinical laboratory test results at the Screening Visit or Check-in (Day -1), which can be confirmed by a single repeat measurement, if deemed necessary:

    • Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) ≥2 × upper limit of normal (ULN).
    • Total bilirubin >1.5 × ULN. If Gilbert's syndrome is suspected, total bilirubin >1.5 × ULN is acceptable if the conjugated or direct bilirubin fraction is <20% of total bilirubin.

11. Estimated glomerular filtration rate <90 milliliters per minute (mL/min)/1.73 m^2, as calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) 2021 equation at the Screening Visit or Check-in (Day -1).

Note: Other protocol-defined Exclusion criteria may apply.