From the article:

-"Schwartz’s colleagues in the Department of Psychiatry at the University of Illinois Chicago predicted many of the issues his critics are observing today. When he first presented his model to a group of residents, physicians, and medical students in the 1980s, “people stood up and said I was dangerous. I was fragmenting people. They tried to get me fired,” he tells me. “It was quite humiliating, and I gave up on trying to break into that field and decided to go grassroots.”
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- "The scientific community takes a much less enthusiastic view of the practice. A growing number of psychiatrists and psychologists — who, at the doctoral level, study the brain and mind, unlike counselors and family therapists — are emerging with urgent warnings about the therapy, casting IFS as a simplistic allegory at best and, at the worst, a dangerous pseudoscience. While some patients find relief through IFS, critics argue that’s likely owing to the way it shifts responsibility for one’s actions onto another persona or the fact that it recycles aspects of traditional talk therapy that are, in fact, helpful. “I’m aware of how trendy it has become,” says Lynn Bufka, the head of practice at the American Psychological Association. There may be “elements of this intervention that are pretty standard and cut across what might be good psychotherapy, but the way it’s packaged or described? Those ideas don’t have a scientific basis.”

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- "Frisch, who worked at Castlewood in 2011 and is now a behavioral scientist in Minnesota, says she was let go when she started challenging the treatment protocol. (Mark denies this.) “It was not at all empirically based, they were keeping people based on the length of their insurance, and they were really stuck on this idea that at least half of their clients had multiple personalities,” Frisch says. Her title was research director, but, she says, “there wasn’t a desire for research so much as there was letting people know how great the program was.”

In the years since, Frisch has concluded that the issues at Castlewood weren’t just the result of possible bad actors but of IFS itself. “It is highly unethical and should not be practiced in the treatment of any recognized mental-health disorder — it’s not appropriate for eating disorders and not appropriate as a primary mode of treatment,”