Please assess the completion status of the following clinical trial:

Trial Title: A Study of Neural Circuit Responses to Catechol-O-methyl Transferase (COMT) Inhibitors

Study Design Characteristics:
- Allocation: RANDOMIZED
- Intervention Model: CROSSOVER
- Observational Model: None
- Primary Purpose: BASIC_SCIENCE
- Time Perspective: None
- Masking: TRIPLE
- Phase: None
- Number of Arms: 2.0

Eligibility Criteria:
Inclusion Criteria:~* Age between 18 and 50 years.~* Subject is right-handed.~* If female, subject is non-lactating, not pregnant, and using a reliable contraception method (i.e. abstinence, intrauterine device (IUD), hormonal birth control or barrier method).~* Subject is able to read and speak English.~* Subject is a high school graduate.~* Subject is able and willing to provide written and informed consent.~* Subject is able to understand and follow the instructions of the investigator, and understand all ratings scales.~* Subject is in good health.~Exclusion Criteria:~* Using cocaine, stimulants (other than THC, nicotine, \& caffeine)amphetamines, hallucinogens, ecstasy, opiates, sedatives, pain pills, sleeping pills or other psychoactive drugs within two weeks of the start of the study OR more than 10 times in the last year.~* Has a current dependence on, or addiction to any psychoactive drug (except nicotine or caffeine) including alcohol.~* Clinically significant medical or psychiatric illness requiring treatment as determined by screening blood tests, medical history, and physical exam performed or reviewed by the study physician.~* Subject has a history of major alcohol related complications within the proceeding 2 years (liver failure/cirrhosis, pancreatitis, esophageal varices, etc.)~* Liver function test ≥ 3 times normal upper limit.~* BAC level \> 0.05% at the beginning of screening visit (within margin of error of detection).~* Has a neurological dysfunction or psychiatric disorder.~* Has severe low blood pressure.~* Has uncontrolled high blood pressure.~* Regular use of any of the drugs on the tolcapone or entacapone contraindications list OR within 2 weeks of drug administration.~* Regular use of SSRIs.~* Has an allergy or intolerance to tolcapone or entacapone.~* Subject has received an investigational drug within 30 days of screening visit.~* Subject is considered unsuitable for the study in the opinion of the investigator or study physician for any other reason.~MRI Exclusion Criteria:~* The subject has metal (metal plates, pins, wires or screws, artificial limb, joint replacement or anything that might have been inserted during an operation) in his/her body.~* Subject has a pacemaker, defibrillator, stent, or any metal implants related to heart/blood flow problems.~* Subject has worked with metals (ie. metallurgy, metal shaving, welding, soldering, etc).~* Subject has been wounded with anything metal (bullet, shrapnel or metal filling).~* Has ever gotten a piece of metal in the eye.~* Has tattoos done with ink containing metal or permanent eyeliner.~* Wears color contact lenses.~* Has a hearing problem or hearing aid, cochlear implant or past ear surgery.~* Has any irremovable dental bridges, dental plates, metal caps or any other non-removable metal in the mouth.~* The subject is claustrophobic.~* The subject is pregnant. (women only)~* Has a IUD. (women only)~* Significantly overweight.

- Gender: ALL
- Minimum Age: 18 Years
- Maximum Age: 50 Years
- Healthy Volunteers: t

Study Arms:
- Tolcapone (Type: EXPERIMENTAL): Drug: Tolcapone 200mg (single dose) administered at study visit
- Placebo (Type: PLACEBO_COMPARATOR): Drug: Placebo for tolcapone administered at study visit

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