Please assess the completion status of the following clinical trial:

Trial Title: Prevention of Stimulant-Induced Euphoria With an Opioid Receptor Antagonist

Study Design Characteristics:
- Allocation: RANDOMIZED
- Intervention Model: PARALLEL
- Observational Model: None
- Primary Purpose: TREATMENT
- Time Perspective: None
- Masking: DOUBLE
- Phase: PHASE4
- Number of Arms: 2.0

Eligibility Criteria:
Inclusion~1. Male and female outpatients~2. age 18-30~3. diagnosis of ADHD by DSM-IV, per clinical evaluation and confirmed by structured interview~4. likeability response (\> 5) on Question #2 of the DRQ-S after an initial test dose of 60 mg of IR MPH.~5. Baseline ADHD severity of \> 20 on the Adult ADHD Investigator System Report Scale (AISRS)~6. Able to participate in blood draws and to swallow pills.~7. Subjects must be considered reliable reporters, must understand the nature of the study and must sign an informed consent document~Exclusion~1. Any current (last month), non-ADHD Axis I psychiatric conditions~2. Ham-D \> 16, BDI \> 19, or Ham-A \> 21~3. Any clinically significant chronic medical condition~4. any cardiovascular disease or hypertension~5. Clinically significant abnormal baseline laboratory values~6. I.Q. \< 80)~7. Organic brain disorders~8. Seizures or tics~9. Pregnant or nursing females~10. Clinically unstable psychiatric conditions (i.e. suicidal behaviors, psychosis)~11. Current or recent (within the past year) substance abuse/dependence~12. patients on other psychotropics~13. Current or prior adequate treatment with MPH~14. known hypersensitivity to methylphenidate~15. Current opioid use (by history and urine screen) or potential need for opioid analgesics during the study~16. acute hepatitis or liver failure (baseline blood tests).

- Gender: ALL
- Minimum Age: 18 Years
- Maximum Age: 30 Years
- Healthy Volunteers: f

Study Arms:
- Naltrexone (Type: EXPERIMENTAL): Arm 1: Naltrexone + SODAS MPH
- Placebo (Type: PLACEBO_COMPARATOR): Arm 2: Placebo + SODAS MPH

Based on this trial design, predict the completion outcome and termination type (if applicable).