Could a Parkinson's drug help with alcohol and ADHD?
NCT ID NCT03904498
First seen Jun 25, 2026 · Last updated Jun 27, 2026 · Updated 1 time
Summary
This study tested whether tolcapone, a drug used for Parkinson's disease, could change how people with both alcohol use disorder and ADHD respond to alcohol and make decisions. 23 adults completed the trial, which involved taking tolcapone or a placebo and then undergoing alcohol challenges, brain scans, and decision-making tests. The goal was to see if the drug affects alcohol cravings, intoxication, and brain activity related to attention and impulse control.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- Tolcapone (Tasmar)
- What this could lead to
- If it works, this could point toward a new treatment option for people with both alcohol use disorder and ADHD.
- What could go wrong
- This was a small, early-phase study with only 23 participants. Results may not apply to everyone, and tolcapone has known liver risks.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
-
Phase 2
Tests whether the treatment actually works, and watches for side effects, in a larger group.
- Participants
-
23 people
The number who actually took part.
- Started
-
Aug 2021
- Finished
-
Mar 2026
- Lead sponsor
-
Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
-
21 to 65 years
- Sex
-
Anyone
- Healthy volunteers
-
Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: 1. Age 21-65. 2. Meets Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) criteria for current Alcohol Use Disorder (AUD) and current Attention-Deficit/Hyperactivity Disorder (ADHD), as assessed by the Structured Clinical Interview for DSM-5 (SCID-5) or WHO-ASRS. 3. Currently not engaged in, and does not want treatment for, AUD or ADHD. 4. Currently not taking any medication for AUD or ADHD. 5. Able to read and understand questionnaires and informed consent. 6. Lives within 50 miles of the study site. Exclusion Criteria: 1. Current DSM-5 diagnosis of any other substance use disorder except Nicotine Use Disorder. 2. Any psychoactive substance use (except nicotine) within the last 30 days, as indicated by self-report and urine drug screen (UDS) 3. Current DSM-5 psychotic, mood, anxiety, obsessive-compulsive, trauma-related, or eating disorder, as assessed by SCID-5. 4. Current suicidal ideation or homicidal ideation. 5. Current use of any psychoactive medication, as evidenced by self-report and UDS. 6. History of severe alcohol withdrawal (e.g., seizure, delirium tremens), as evidenced by self-report and assessment with Clinical Institute Withdrawal Assessment for Alcohol-Revised (CIWA-Ar). 7. Clinically significant medical problems such as cardiovascular, renal, gastrointestinal, or endocrine problems, as evidenced by medical history and physical exam. 8. Past alcohol-related medical illness, such as gastrointestinal bleeding, pancreatitis, or peptic ulcer. 9. Current or past hepatocellular disease, as indicated by verbal report, or elevations of alanine aminotransferase (ALT) or aspartate aminotransferase (AST) greater than the upper limit of the normal range at screening. 10. Females of childbearing potential who are pregnant (by plasma HCG), nursing, or who are not using a reliable form of contraception. 11. Current charges pending for a violent crime (not including DUI-related offenses). 12. Lack of a stable living situation. 13. Presence of ferrous metal in the body, as evidenced by metal screening and self-report. 14. Severe claustrophobia or morbid obesity that preclude placement in the MRI scanner. 15. History of neurological disease or head injury with \> 2 minutes of unconsciousness.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
-
University of Colorado Anschutz Medical Campus
Aurora, Colorado, 80045, United States
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