But Dr. Koob, like many of the researchers and academic institutions playing pivotal roles in the trial, has had close ties to the alcoholic beverage industry. Dr. Koob served from 1999 to 2003 on the medical advisory council of the Alcoholic Beverage Medical Research Foundation, now called the Foundation for Alcohol Research, an industry group that also provided him research grants of up to $40,000 a year between 1990 and 1994, said John Bowersox, a spokesman for the N.I.H.’s alcohol institute.

Indeed, many of those involved in the study have financial links — either personally or through an institution — to alcohol industry money.

Harvard, the hub of the clinical trial, has a long relationship with the alcoholic beverage industry. In 2015 the university accepted $3.3 million from the Foundation for Advancing Alcohol Responsibility, a group founded by distillers, to establish an endowed professorship in psychiatry and behavioral science. Harvard’s School of Public Health also came under fire in 2005 when a professor teamed with Anheuser-Busch to promote the health benefits of beer, and Anheuser donated $150,000 to fund scholarships for doctoral students.

One of the trial’s principal investigators, Dr. Eric Rimm of the Harvard T. H. Chan School of Public Health, has acknowledged through various financial disclosures that he has been paid to speak at conferences sponsored by the alcohol industry and received reimbursement for travel expenses. He said it had been at least eight or nine years since those events, and he has no current relationship with the alcoholic beverage industry.

Dr. Diederick Grobbee, another principal investigator, who is based in the Netherlands and is in charge of clinical sites outside the United States, said in a telephone interview that he has received research money from the International Life Sciences Institute, an industry group that supports scientific research.

In Baltimore, the trial will be run by Dr. Mariana Lazo-Elizondo of Johns Hopkins, who received research grants in 2013 and 2014 totaling $100,000 from the Alcoholic Beverage Medical Research Foundation. She declined to be interviewed.

In Copenhagen, the lead researcher will be Dr. Lars Ove Dragsted, who disclosed in a scientific paper last year that he has conducted research at institutions that received industry support. He has not responded to requests for comment.