For almost a decade, cleaning rituals ruled Kathrine’s life. The middle-aged resident of Bergen, a coastal town in the southern tip of Norway, was consumed by a fear of germs and contamination that led to endless cycles of tidying, vacuuming and washing. “I realized that I was facing a catastrophe,” Kathrine Mydland-aas, now 41, recalls. “I couldn’t help the kids with homework, couldn’t make dinner for them, couldn’t give them hugs. I didn’t do anything but cleaning. I tried to quit, but the rituals always won.”

Last year, around nine years after Mydland-aas’s cleaning rituals began, a psychologist diagnosed her with obsessive-compulsive disorder (OCD) and referred her to a clinic at the Haukeland University Hospital in Bergen. There, a team was administering a behavioral therapy for the condition that, to Mydland-aas’s surprise, was only four days long. “I thought, what can they do in four days?” she says. “[But] it changed my life.”

Mydland-aas is one of more than 1,200 people who have received the Bergen four-day treatment for OCD, a concentrated form of exposure therapy designed by two Norwegian psychologists, Gerd Kvale and Bjarne Hansen. The four-day protocol has recently gained international attention for its effectiveness and efficiency—last month Time magazine named the pair, who are both currently affiliated with the Haukeland University Hospital and the University of Bergen, as two of this year’s 50 most influential people in healthcare.

“It’s amazing that you can so get much done in such a small amount of time,” says Avital Falk, a clinical psychologist who directs an intensive treatment program for OCD and anxiety at Weill Cornell Medicine and NewYork Presbyterian. OCD treatment regimens typically involve weekly hour-long sessions spread out across several months, but more clinicians are adopting concentrated therapy. “Intensive treatment in general has been getting a lot more attention in different formats that can be anywhere from three hours a week,” Falk says. “Ten to 12 hours a week, all the way to the Bergen method, which does everything in four days.”

Kvale has been practicing intensive therapies for various disorders, including phobias and chronic fatigue, since the early 1990s. Over the years, she noticed a lack of effective psychological treatments for people with OCD in Norway, which spurred her interest in creating a concentrated therapy for the disorder. In 2010, she asked executives at her employer, the Haukeland University Hospital, to open a new clinic where she could develop this method—and they agreed. Kvale immediately recruited Hansen, who had spent many years practicing the so-called “LEan into The anxiety” or LET-technique—a method of encouraging individuals with OCD to focus specifically on anxiety-eliciting moments—which eventually formed the core foundation of the Bergen treatment. The duo completed the design of the four-day protocol by fall 2011, and tested the first group of patients in June of the following year. “It worked out exactly the way the we expected it to,” Kvale recalls. “The change we saw during those four days was really immense.”

The Bergen method works in three stages: On the first day, therapists provide patients with information about OCD and help them prepare for the exposure tasks they will engage in over the next two days. During the exposure part of the protocol, people face their fears head-on—for example, if someone is frightened of contamination, therapists suggest that they choose an object or surface that might trigger anxiety or discomfort, and then touch it. “We encourage patients to pay attention to the moments when they feel the urge to start taking control to reduce anxiety or discomfort,” Kvale explains. “And to use these as turning points for change.” Participants set aside the last day for planning how to maintain the behavioral changes gained during therapy after leaving the clinic.

The two middle days serve as a single prolonged therapy session, one of several aspects that makes the Bergen method effective, according to Kvale and Hansen. Other key features include the usage of the LET-technique during exposure sessions and the format of the treatment, in which a group of three to six therapists work as a team with the same number of patients. This setup is important, Kvale says, because it provides tailored care for each individual while also letting patients observe others going through the same process of change.

Earlier this year, Kvale, Hansen and their colleagues reported findings from a long-term analysis of the treatment’s effects. The study, published August in Cognitive Behaviour Therapy, revealed that 56 of 77 patients remained in remission four years after treatment—and that 41 of the 56 had fully recovered. Treatment outcome was independent of whether participants had previously undergone therapy or were on selective serotonin reuptake inhibitors (SSRIs), such as Cipralex, commonly used medications for OCD. When the team members compared their findings to published analyses of other less-intensive exposure treatments, they found that the Bergen technique led to significantly higher rates of remission and recovery.

“I was very impressed [with the results],” says Martin Franklin, a clinical psychologist at the University of Pennsylvania who is one of the Norwegian psychologists’ close collaborators but was not involved in this study. “The follow-up data [showing] that people are maintaining their gains four years out is really interesting.” However, Franklin notes that it is too early to say whether the Bergen method is more effective than other, longer, forms of exposure and response prevention (ERP) therapies. For one thing, the team’s analysis lacked an untreated control group, so one cannot rule out the possibility that patients examined were simply more likely to respond to therapy. In addition, this study only compared the Bergen method with prior OCD studies with long-term follow-up assessments. As a result, “you’re not necessarily comparing to the best trials done,” Franklin adds.

Whether the Bergen method will work for patients in the United States or other countries with significantly different cultures, is another open question, Franklin says, but one that may soon have answers. Kvale and Hansen have already started training groups in Iceland and Sweden, and will begin working with teams in Houston next year. The pair notes that before disseminating this treatment on a large scale in different countries, they will conduct randomized controlled trials to assess how well it works in the new cultural settings.

Falk notes that differences in health care systems may pose a challenge to expanding use of the Bergen technique. In Norway, the government covers the Bergen treatment through a universal health care system, which is not present in the U.S. Intensive treatment programs at American clinics can be expensive—often in the thousands of dollars range—and insurance companies do not always help cover the costs. Even if a patient undergoing concentrated therapy receives the same number of total treatment hours as someone who opts for more long-term, once-a-week care, “paying for that all upfront can be a barrier to access,” Falk adds.

As the treatment is used more widely, the Norwegian pair will also be working with researchers from several countries to investigate the genetic, epigenetic and neurobiological changes that occur when patients undergo the Bergen four-day treatment. The Bergen protocol’s concentrated structure makes it an ideal paradigm to examine how the brain can rapidly learn new emotional processes, says Kerry Ressler, chief scientific officer at McLean Hospital in Massachusetts and one of the scientists involved in this project. Other goals of this work, he adds, include identifying biological markers—in blood, saliva or through neuroimaging—that can pinpoint patients who will best respond to this type of treatment and to gain new insights to help inform future therapies.

In the meantime, for Mydland-aas and many other patients, the Bergen four-day treatment has proved to be a transformative experience. Mydland-aas says her OCD is gone; she is no longer occupied by extensive cleaning rituals and is able to engage in family activities, such as swimming in public pools, that she was unable to before. “Before my life was a struggle, it was about surviving every day,” she says. “I now enjoy all the things I can do, and I have a very healthy relationship with my family and friends.”