Cannabidiol for Alcohol Dependence in Adults Seeking Abstinence: A Phase II Placebo‑Controlled Trial

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What is this study about?

The trial focuses on alcohol dependence, a condition in which a person finds it difficult to stop drinking even when it causes problems. The medication being tested is Cannabidiol, given as an oral solution at a dose of 600 mg per day, and it is compared with a placebo, which looks the same but contains no active ingredient.

The purpose of the study is to see whether the medication can help people reduce or stop drinking. Participants will be randomly assigned to receive either the medication or the placebo for several weeks, during which they will attend regular visits, complete a drinking diary called the Timeline Follow-back (a questionnaire that asks about alcohol use each day), and provide blood samples for a test called Carbohydrate Deficient Transferrin (a lab measure that indicates heavy alcohol consumption). The study also looks at how the drug affects the body’s endocannabinoid system, a natural system that interacts with compounds like cannabidiol, and monitors safety and side effects throughout the trial.

1 randomization and assignment

after joining the study, you will be randomly assigned to receive either placebo or cannabidiol.

placebo contains no active drug, while cannabidiol is the test medication.

2 receiving the study medication

you will be given an oral solution to take at home.

the cannabidiol solution contains 600 mg of the active substance per dose; the placebo solution looks the same but contains no active ingredient.

3 taking the medication

the assigned oral solution is taken by mouth according to the schedule provided by study staff.

the dose is 600 mg for the active medication; the frequency and total length of treatment will follow the study protocol.

4 regular follow‑up visits

you will attend scheduled visits during the trial.

at each visit you will complete the timeline follow‑back (tlfb) questionnaire, which records your alcohol consumption over the previous period.

a blood sample will be taken to measure carbohydrate deficient transferrin (cdt), a marker that reflects recent alcohol intake.

5 safety and tolerability monitoring

during the study you will be asked to report any side effects or new symptoms.

study staff will evaluate the safety of the medication and record any adverse events.

6 final assessment and study completion

at the end of the treatment period you will have a final visit.

the final visit includes the last tlfb questionnaire, a final cdt blood test, and a review of your overall experience in the trial.

Who Can Join the Study?

Be a man or woman aged between 18 and 65 years.
Have a diagnosis of moderate or severe Alcohol Use Disorder (AUD) as defined by the DSM‑5 (the handbook doctors use to classify mental health conditions).
Be able to sign a voluntary informed consent form, meaning you understand the study and agree to join without pressure.
Have had at least 8 “heavy drinking days” in the past 30 days – that is, 4 or more drinks in one day for a woman, or 5 or more drinks in one day for a man.
If you could become pregnant or cause pregnancy (childbearing potential), agree to use an approved method of contraception from the time of screening for the whole study.
Provide at least two “locators,” which are contact details (such as phone numbers or email addresses) that researchers can use to reach you.
State that you want to cut down on or stop drinking alcohol.

Who Cannot Join the Study?

If you are currently experiencing alcohol withdrawal that scores higher than 7 on a standard assessment (called CIWA‑Ar), you cannot join the study.
If you are pregnant or are currently breastfeeding, you cannot join the study.
If you are taking any medicines that could interfere with the study drug—such as other cannabis products, other alcohol‑addiction treatments, or drugs that affect certain liver enzymes (CYP3A4, CYP2C19, CYP3A5, CYP3A7) or have a very narrow safety range—you cannot join the study.
If you are allergic to any part of the study medication, you cannot join the study.
If you are receiving any formal treatment for alcohol use disorder (except for support groups like AA or other 12‑step programs), you cannot join the study.
If you have been hospitalized for a psychiatric condition in the past year (except for detoxification or a long stay in the emergency department), you cannot join the study.
If a urine test shows the presence of THC (marijuana), cocaine, or opioids, you cannot join the study.
If you have a serious medical problem that makes you very ill—such as severe alcohol withdrawal needing hospital care or major liver problems—you cannot join the study.
If you have been diagnosed with certain mental illnesses, such as schizophrenia, schizoaffective disorder, or bipolar disorder, you cannot join the study.
If the study doctor believes you are at high risk for a strong emotional or behavioral reaction (for example, serious personality problems, antisocial behavior, major current stress, or little social support), you cannot join the study.
If you are currently very suicidal (as measured by a standard questionnaire called the C‑SSRS), have tried to kill yourself in the past year, have had a serious suicide attempt that required hospitalization, or have serious thoughts of harming others, you cannot join the study.
If you have had a severe Traumatic Brain Injury with loss of consciousness for more than 24 hours, you cannot join the study.
If you currently have a mild cannabis use disorder or a moderate to severe disorder with any other drug (except alcohol or nicotine), you cannot join the study.
If routine lab tests show major problems—such as poor liver function, serious issues with your blood count, or major metabolic abnormalities—you cannot join the study.
If you have ongoing legal issues that are likely to lead to jail time within 12 weeks of starting the study, you cannot join the study.

Where you can join this trial?

Verified and Recommended Sites

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Verified Sites

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Other Sites

Site Name	City	Country	Status
Hospital Universitario 12 De Octubre	Madrid	Spain

Trial status

Country	Status	Recruitment Start
Spain	Not yet recruiting	04.05.2026

Trial locations

Investigated drugs:

CANNABINOL

Cannabidiol is a non‑psychoactive substance derived from the cannabis plant. In this study it is given as an oral liquid solution. The trial is testing whether cannabidiol can help people who are dependent on alcohol to drink less and achieve abstinence, and whether it can improve a blood test (carbohydrate‑deficient transferrin) that reflects alcohol use.

Investigated diseases:

Alcohol abuse

Alcohol dependence – Alcohol dependence is a condition where a person feels a strong need to drink alcohol regularly. Over time, the individual may find it hard to stop drinking even when they want to. Drinking becomes a central part of daily life and can lead to increasing amounts being consumed. The need for alcohol grows, and people may start to experience cravings when they are not drinking. As the condition continues, the person may notice that they think about alcohol often and plan their activities around it.

Trial ID:

2023-504439-42-03

Protocol code:

PLACONCANALDE

Trial Phase:

Therapeutic exploratory (Phase II)

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