Twenty years ago, Claudia Christian was on the trajectory that had consumed countless Hollywood stars. She’d had her moments of fame—first as Commander Susan Ivanova in the 1990s sci-fi television series Babylon 5. She had a role in the critically beloved Judd Apatow comedy Freaks and Geeks, a Playboy pictorial, and a long list of prominent lovers that included George Clooney and the late Dodi Fayed.

But by the early oughts, Christian was struggling to stay afloat. Her drinking had spiraled from social to bingeing. She’d abstain for weeks at a time, and then find herself at Ralph’s Grocery Store near her Los Angeles home first thing in the morning, tossing crème de menthe and Drambuie into her cart with the loud pronouncement she was planning on making soufflés. (“Everybody was so on to me,” she says, “especially the kid who said, ‘Isn’t it a little early for this stuff?’”)

She repeatedly tried to stop. “I went to dozens of Alcoholics Anonymous meetings in two different countries. I tried moderation. I tried tapering. I tried hypnosis. I tried rehab. I tried everything.”

But in 2009, as she was leaving a California detox center, she noticed a flyer for a drug called Vivitrol, an injectable form of the opioid blocker naltrexone. It prevents endorphins, or feel-good hormones, which are released when people drink, from reaching their target, the opioid receptors.

The drug worked—and Christian, who continues to act in feature and television films, has become an evangelist for an approach to alcohol use disorder that is widely known in other countries but little used in the United States.

Christian, 50, has produced, narrated, and is the protagonist of a new documentary called One Little Pill, which details her recovery with a treatment pioneered in Finland called the Sinclair Method. (The film is available for rental on Vimeo and VHX.) In 2013, she started a public charity, the C3Foundation.org, whose goal is to educate patients and physicians on the method she credits with saving her life. It also has a branch in the U.K.

The use of the drug that helped Christian was pioneered by the late American neuroscientist David Sinclair, who developed the idea while studying rats specially bred to crave alcohol. He found that when he withdrew alcohol bottles from the rats for a few days or weeks, the rats returned to them with more determination—and thirst—than ever before. He repeated his experiment several times, each time noting that the rats’ benders would last progressively longer after periods of abstinence. “What that showed us,” Sinclair says in the film, is that the cold-turkey approach “not only failed to work—it was backwards.” All the effort getting people into detox and abstinence, Sinclair says, is counterproductive—and it might make some people worse.

He published his initial findings, but they were not popular among American researchers, who believed that a strict abstinence policy was best for all problem drinkers. So in the early 1970s Sinclair moved to Finland, which has a severe binge-drinking culture, and which also generously funded scientific approaches to problem drinking. Sinclair believed that drinkers develop problem habits through a strictly chemical process. With each drink, the brain releases endorphins, or feel-good hormones. Drinkers experience a “reward” once the endorphins reach their target, the brain’s opioid receptors. Habitual drinking repeatedly strengthens the synapses, reinforcing the “reward” imbibers get when they drink. It also results in a predictable pattern: growing thoughts and cravings for alcohol that develop into a compulsion.

By using naltrexone, a 40-year-old generic opioid blocker that has few side effects, an hour before drinking, Sinclair found, you could effectively block the reward of the alcohol. By using this protocol repeatedly, the cravings and the obsession with drinking subsides, he found. His method has been tried on thousands of patients in three facilities he co-founded Finland since the late 1990s, and has been shown to reduce drinking to normal levels in 78 percent of patients, said Jukka Keski-Pukkila, CEO of the Contral Clinics.

Christian, who found the drug by accident, has devoted her time and resources to educating others. “I wish someone had done it for me when I was searching for an answer to my alcohol problem,” she says on the film.

Her fame draws attention to the cause, and attracts nearly 6,000 visitors to her site per month. She refers them to local doctors who prescribe naltrexone, which was approved by the FDA for the treatment of alcohol abuse in 1994. It is seldom used.

According to a spokesman at the National Institutes for Alcohol Abuse and Alcoholism, only about 1 percent of Americans are ever prescribed medications for the treatment of alcohol use disorder, the term for problem drinking now used by the DSM-5. It connotes a spectrum from mild to moderate to severe, and the CDC estimates that some 18 million Americans have AUD.

This past week, Christian flew from her home in L.A. to Washington, D.C., to meet with substance use counselors at their annual conference to try to draw attention to the method. She was not encouraged by the reception she got: In the U.S., abstinence-only models have dominated the alcohol treatment landscape since the advent of Alcoholics Anonymous in 1939. “People just want to know how they can monetize treatment,” Christian says. (Under Obamacare, insurance companies are required to pay for treatment for alcohol and substance use disorders.) Meanwhile, only 12 people showed up at a talk about prevention, says Jenny Williamson, executive director of the C3Foundation.

Stephen Cox, a University of Kentucky psychiatrist, said he was not surprised. Cox has prescribed naltrexone according to Sinclair’s protocol to about 100 patients over the past eight years. Because the method seems so counterintuitive in a country where most believe that anyone with a drinking problem should never touch alcohol again, Dr. Cox invites family members to hear an explanation about how the drug-plus-drinking combination works. “If I don’t, chances are the wife or husband will hit the roof and report me to the medical licensing board. I tell them that I was a personal friend of David Sinclair’s, and just having that knowledge can help boost the level of compliance and support.” Of his 100 or so patients who have used the drugs, about 75 percent of them return their drinking to moderate levels, he said.

But Cox adds that the drug is not effective on everyone. “Some people just need to abstain,” he said. “Not everybody, but some.”

Certainly Christian believed that was her only choice as her drinking worsened in the mid-2000s. “There was a slice of Claudia way in the back of my brain saying, ‘What the hell are you doing?’ But that voice was so small, and the addict voice was so loud,” she says in the film. “The absolutely terrifying thing about it is that there is somebody who wakes you up at 6 in the morning and puts you in your car to go buy alcohol. Who was that person? It wasn’t me.”

Christian’s candor has deepened her fans’ appreciation, and many of them have been heartened to discover that the invincible space queen suffered problems much like their own, as she first depicted in her 2012 memoir, Babylon Confidential: A Memoir of Love, Sex, and Addiction. She details a glamorous life at Paris restaurants and yachts in the Mediterranean, but doesn’t hide her dark moments, either. Her 14-year-old brother was killed by a drunk driver while riding his bike in Texas, tearing a hole in her close-knit family. At 15, Christian was raped by a neighbor, but felt too ashamed to ever report the crime. She underwent several abortions, and suffered multiple miscarriages.

Trauma is a known risk factor for developing alcohol use disorder. And eventually, Christian’s only solace seemed to be in numbing herself. One morning, she found herself at a bus stop, shakily pouring tiny vodka bottles into her orange juice, not caring whether her fans spotted her or not. By then, she says, “my brain had changed. I could feel it. I needed that drink in the morning just to feel normal.”

Her mother insisted on rehab, which was rooted in the faith-and-abstinence-based principles of Alcoholics Anonymous. “I have plenty of faith,” she says today, “but I didn’t think praying was going to fix what was going on in my brain. It was physiological—and I wanted a physiological answer.”

In the film, Christian also traces the experiences of other drinkers who’ve successfully used the method. She follows Patricia, a Napa Valley winemaker whose drinking habit was edging north of a bottle and a half a day before she discovered naltrexone. Until then, Patricia says in the film, she was trying to weigh how to stay in the field she loved—and in which she’d achieved success—or leave it entirely. Suicide, she said, crossed her mind. For two years, she has taken the drugs according to protocol, and rarely overdrinks.

Christian says that the time spent not drinking—and recovering from drinking—offers users of the Sinclair Method positive reinforcement. “You can exercise, take the dog for a walk,” she says, “or have sex—and remember it!”