Kirby Brown was not afraid to take risks. The 38-year-old decorator learned to ride horses as a child and surfed giant waves in Mexico's Sea of Cortez as an adult. She was not reckless, though. “She loved adventure, but she was very safety-conscious,” says her mother, Virginia Brown. So when Kirby decided in 2009 to take part in a spiritual retreat in the Arizona desert organized by well-known self-help guru James Arthur Ray, she probably did not think her life was in danger.

Intended as a “catalyst for personal transformation,” the five-day retreat included 36 hours of meditation without food or water, followed by a ceremony in a makeshift sweat lodge. Kirby and one other participant did not survive the ritual; a third became comatose and died a week later. Eighteen others were hospitalized for injuries ranging from heat exhaustion to kidney failure. “Basically, these people were boiled,” says Christine Whelan, a visiting sociologist at the University of Pittsburgh who studies the self-help industry.

The Arizona deaths, as well as suicides and psychotic episodes that have resulted during and after similar events, are extreme examples of the dangers that can lurk in the U.S.'s $12-billion or so self-help industry. The self-help philosophy stems from the commonsense assumption that many people are capable of coping with various problems—from the financial to the psychological—on their own; paid professional assistance is not always necessary. The broad umbrella of “self-help” approaches includes retreats such as Ray's, support groups that aim to improve mental health or change behavior, and more than 45,000 books and apps designed to help people live happier lives. Self-help books in particular are so popular that there is a separate best-seller list in the New York Times mainly devoted to them.

Although dozens of studies suggest that research-based self-help can provide real benefits—in particular, for anxiety, depression and drug addiction—more than 95 percent of self-help books and programs have never been subjected to scientific scrutiny, according to John C. Norcross, a professor of psychology at the University of Scranton and co-author of Self-Help That Works (Oxford University Press, 2013). People can, however, better protect themselves from potentially dangerous self-help rituals, Norcross and other investigators say, by learning to recognize warning signs of dubious experts and by understanding how peer pressure impairs judgment.

Under Scrutiny
Researchers have assessed only an estimated 50 self-help programs for safety and efficacy, Norcross says. And the resulting evidence shows that some programs do work. The best-studied approaches for combating psychological problems, for example, emphasize the techniques of cognitive-behavior (CBT) therapy: learning to detect and deflect anxious, depressing or otherwise negative thoughts. A 2013 Cochrane review—considered a gold standard for large systematic reviews of health research—notes, for instance, that when it comes to anxiety disorders, seeing a therapist in person is most likely superior to self-help based on books and on apps but that “self-help is probably better than no treatment.”

Aside from examining approaches based on CBT, researchers have also devoted a good deal of attention to “12-step” groups, such as Alcoholics Anonymous (AA), in which members urge one another to follow certain guidelines to cope with their addiction. Whereas a 2006 Cochrane review of AA concluded that “no experimental studies unequivocally demonstrated” its effectiveness, many observational studies show that those who willingly participate are more likely to quit drinking than those who do not. (Unlike experimental studies, observational studies do not involve researchers changing the conditions that participants experience to determine if an intervention is effective.) One such study demonstrated that two thirds of people who stuck with the program for at least 27 weeks were still refraining from alcohol 16 years later. Yet according to AA's own surveys, the majority of people who come to the program for the first time are no longer attending after six months.

Peer Pressure
Sitting on the couch at home and reading a self-help manual might not seem like a dangerous activity. But anyone who blindly follows ill-advised instructions, such as eating a nutrient-poor diet, is asking for trouble over the long term—starting, at the very least, with gum disease in the case of the diet.

Self-help becomes particularly perilous whenever someone joins a group and peer pressure begins to counteract one's better judgment. Twelve-step programs, for example, typically remind participants not to “play doctor” because members have sometimes urged newcomers to stop taking psychiatric medications on the grounds that drugs of any kind could impede recovery. Not wanting to go against the group, vulnerable individuals have obliged and subsequently relapsed into depression, psychosis, anxiety or other disorders, in some cases resulting in suicide.

Add physical and emotional stress to peer pressure, and you have a potentially more dangerous brew. Seminars like the one Ray organized in the Arizona desert are known among psychologists as “large-group awareness trainings.” During these kinds of retreats, which can include vague promises about self-improvement, a charismatic leader generally guides a group of people through several continuous days of meditation, self-hypnosis, fasting, sermons and discussions in which they share intimate details about their lives. All the while, the leader alternately rebukes and praises the participants—and denies them basic needs—to leave them psychologically vulnerable.

Before they even entered the sweat lodge, for example, Kirby and her fellow participants received limited amounts of food, water, bathroom breaks and sleep for several days. Hunger, thirst and sleep deprivation alone can profoundly stress the body and alter consciousness—but the ceremony was also emotionally taxing. Ray claimed at the time that the ordeal would bring them close to death, followed by a spiritual rebirth. (My repeated requests for an interview with Ray, made to his representative, were to no avail.)

Such stressful conditions frequently produce strong emotions ranging from despair to ecstasy and forge a sense of intimacy and affection between strangers. This sense of camaraderie makes people all the more susceptible to peer pressure and more obedient of authority figures. Stress also reduces blood flow to regions of the brain important for planning, self-control and reasoning. Even apparently minor stresses, such as being denied access to the bathroom, can wear down one's ability to resist social pressure, Whelan says.

The end result is that even highly intelligent and educated people can behave irrationally—say, staying in a tarp-covered hut so overheated that people begin to lose consciousness. The smartest individuals are, in fact, often at the highest risk because they tend to think they are immune to peer pressure. One of the participants who died carried a woman to safety before returning to the lodge. Apparently he did not realize he was in exactly the same kind of danger. “When people saw what happened in [Arizona], most of them said to themselves, ‘Those people were idiots.’” Whelan says. “We like to think we are different, but we're not, and these are really powerful techniques. If you had been there, you might be dead, too.”

Given how easily the brain succumbs to peer pressure, experts recommend avoiding group situations in which a leader deliberately induces stress—a technique that does not lead to helpful psychological changes according to the relevant studies. If you do wind up in such circumstances, be aware that they can profoundly alter your thinking and behavior; therefore, do not make life-changing decisions.

What to Look For
What, then, are the critical elements of good self-help programs? First, overcoming depression, anxiety, addictions or other disorders typically requires learning new coping skills over many months or years, not in a matter of days or weeks. This is why successful forms of self-help prepare one for a long period of self-improvement and why groups like AA suggest long-term attendance. Intense, one-time experiences typically do not provide the ongoing support needed for lasting change.

Second, good programs have independent data showing their effectiveness, not just anecdotes, and they are generally adapted from techniques shown to work in more conventional therapy administered by professionals. If there is no published literature supporting a program—no matter how popular it may be—that is a red flag.

Whelan now serves on the advisory board of Seek Safely, an organization set up by the Brown family that offers tips to those who might be attracted to potentially dangerous programs. Seek Safely has also written a pledge that self-help gurus can sign as a way of promising to take the necessary safety precautions and to avoid using stress to make people more submissive.

Ray, who has rebooted his self-help business, has not signed. The biography on his Web site does not mention the deaths in the sweat lodge, his subsequent conviction for negligent homicide or his incarceration for 20 months—although he briefly alludes to them in old blog entries. In addition, a video prominently displayed on the home page features his prescandal 2007 appearance on The Oprah Winfrey Show.

Ultimately, of course, looking for a signature on a safety pledge is no substitute for doing your homework, checking out scientific claims and maintaining a healthy dose of skepticism. Realizing that anyone's instinct for self-preservation can, under the right conditions, simply be erased should go a long way toward keeping you from harm.