Christopher Massimine is trying not to lie.He’s trying not to lie when his wife asks him whether he has sorted the recycling, or when his mother-in-law’s friend Mary Ann asks whether he liked the baked appetizers she brought over.He’s trying not to lie to his therapist, who has him on a regimen of cognitive behavioral therapy to help him stop lying. And he’s trying not to lie to me, a reporter who has come to interview him about how a lifetime of lying caught up with him.This effort began around 15 months ago, when Mr. Massimine resigned from his job as managing director of the Pioneer Theater Company in Salt Lake City after a local journalist reported that he had embellished his résumé with untrue claims.The résumé, it turned out, was the tip of the iceberg. Over the course of many years, he has since acknowledged, he lied prolifically and elaborately, sometimes without any discernible purpose.He told friends he had ascended Mount Everest from Tibet (he was actually in a hotel room in Cambodia) and attended Burning Man (on closer examination, his photographs proved to have been taken in Queens.)He told journalists he was born in Italy. (New Jersey.) He told school friends his birthday was in September. (May.) He told his wife he was having an affair with Kourtney Kardashian. (Not true.)When his binge of lying was exposed, it left Mr. Massimine’s life in tatters, threatening his marriage and discrediting his early success in the world of New York theater.He spoke to The New York Times to address what he described as a fundamental misunderstanding: These were not the lies of a calculating con artist, but of a mentally ill person who could not help himself.Mr. Massimine, talking with his wife, Maggie, has tried to identify the facial tics he experiences when lying.He is not the first to suggest that certain kinds of lying are a compulsion. In 1891, the German psychiatrist Anton Delbrück coined the term pseudologia fantastica to describe a group of patients who, to impress others, concocted outlandish fabrications that cast them as heroes or victims.That argument is advanced in a new book by the psychologists Drew A. Curtis and Christian L. Hart, who propose adding a new diagnosis, Pathological Lying, to the Diagnostic and Statistical Manual of Mental Disorders.Psychiatry, they argue, has long misidentified this subset of patients. Rather than “dark, exploitative, calculating monsters,” they argue, pathological liars are “often suffering from their own behavior and unable to change on their own.” These liars, the psychologists argue, could benefit from behavioral therapies that have worked with stuttering, nail-biting and trichotillomania, a hair-pulling disorder.Just before his fabrications were exposed, Mr. Massimine checked into a psychiatric hospital, where he was diagnosed with a cluster B personality disorder, a syndrome which can feature deception and attention-seeking. For many of the people close to him, a diagnosis made all the difference.“He’s not just a liar, he has no control over this,” said his wife, Maggie, 37, who admitted that, at several points, she had considered filing for divorce. “That really was the turning point for me, when I had an understanding of it as an illness.”Since then, she has thrown herself into the project of helping her husband recover. “It’s similar to Tourette’s,” she said. “You acknowledge that it’s their illness that’s causing them to do this, and it might be a little odd and uncomfortable, but you move past that.”A call from Mount EverestIn 2018, Mr. Massimine posted messages and photos on Facebook pretending to be near Mount Everest in Tibet.Maggie remembers, with painful clarity, the day in 2018 when she realized the breadth and depth of her husband’s problem.“I’m in tibet,” his email said. “Please don’t be mad.”He had attached a photograph of two men, a Sherpa and a fair-haired alpinist, with Himalayan peaks looming in the background. He had managed to sneak into China with the help of kind Buddhist monks, who led him as far as Everest Camp 2, he told her. “This is Tsomo,” he wrote. “He is awesome and if he comes to the USA you’ll love him.”Maggie stared at the picture, which he had also posted on Facebook; it didn’t make sense. Mr. Massimine, her husband of five years, had told her he was on vacation in Cambodia. He had not given himself time to acclimate to the elevation of Everest Base Camp; he had no mountaineering experience; he didn’t have a Chinese visa.“At first, I thought, Why is he posting this when it could get him killed?” she said. “And then, the crazier his posts got, I was like, This isn’t real. None of this is real.”That weekend, with help from her friend Vanessa, she began a “deep dive,” reviewing all of his Facebook posts and email accounts. She discovered elaborate deceptions — voice impersonators, dummy email accounts, forged correspondences. She was terrified, she said. “Who is this person?” she recalls thinking. “Who did I marry?”Christopher Massimine’s flair for theater emerged early.via Lawrence MassimineMr. Massimine is tall, handsome and eager to please. He grew up on a cul-de-sac in Somerset, N.J., the only child of a nurse and an auditor. His flair for theater emerged early — at 10, he wrangled the members of his Cub Scout troop into performing “A Knight’s Tale,” a play he wrote and scored. Family photos show him in costume, a fair-haired boy with fangs, a knight’s armor, an eye patch.The lying started early, too. He says it began in the second grade, when, nervous about bringing home a B plus in math, he told his parents that he had been invited onto the stage at school to sing a duet with an actor from “The Lion King.”Lying became a “defense mechanism,” something he did to calm his anxiety, usually without pausing to consider whether he would be believed. “It was just something where I kind of pulled the trigger and hoped for the best,” he said.In interviews, friends recalled this behavior, which they described as “tall tales” or “embellishments” or “campfire stories.” It never seemed malicious, said Jessica Hollan, 35, who was cast opposite him in a middle school production of “A Midsummer Night’s Dream.”“It was more just like, you caught a minnow, and then it became a swordfish,” she said.Maggie shared a wedding photo from 2013. No one called him out on it, said Lauren Migliore, 34, who got to know him in college. She recalled him as a loyal, affectionate friend but sensitive and needy, “like a little puppy.” “I always thought it came from a place of insecurity,” she said. “I never thought it was worthy of mentioning. It was an attention thing.”By the time he met Maggie, Mr. Massimine was a successful theater producer with a tendency to extreme workaholism. Co-workers recalled his pulling all-nighters as productions approached, sometimes forgetting to shower or change clothes.This intensity propelled him upward through the industry; at 29, he was named chief executive of the National Yiddish Theatre Folksbiene, where he laid the groundwork for a runaway hit, a production of “Fiddler on the Roof” in Yiddish.But it hadn’t been good for the marriage. Now, Maggie understood that her husband’s work habits were not her only problem. They separated for a few months. Then she softened — maybe, she told herself, he was lying because she made him feel inadequate — and they got back together. He started therapy and went on an antidepressant medication.They spent months sifting through everything he had ever told her about his life, “just figuring out fact from fiction,” she said.A small group of prolific liarsVironika Wilde said she lied frequently as a teenager to “produce a moment of empathy in other people.”Ian Willms for The New York TimesIn 2010, when researchers from Michigan State University set out to calculate how often Americans lied, they found that the distribution was extremely skewed.Sixty percent of respondents reported telling no lies at all in the preceding 24 hours; another 24 percent reported telling one or two. But the overall average was 1.65 because, it turned out, a small group of people lied a lot.This “small group of prolific liars,” as the researchers termed it, constituted around 5.3 percent of the population but told half the reported lies, an average of 15 per day. Some were in professions, like retail or politics, that compelled them to lie. But others lied in a way that had no clear rationale.This was the group that interested Dr. Curtis and Dr. Hart. Unlike earlier researchers, who had gathered data from a criminal population, the two psychologists set about finding liars in the general public, recruiting from online mental health forums. From this group — found “in mundane, everyday corners of life,” as Dr. Hart put it — they pieced together a psychological profile.These liars were, as a whole, needy and eager for social approval. When their lies were discovered, they lost friends or jobs, which was painful. One thing they did not have, for the most part, was criminal history or legal problems. On the contrary, many were plagued by guilt and remorse. “I know my lying is toxic, and I am trying to get help,” one said.This profile did not line up with the usual psychiatric view of liars, who are often diagnosed with Antisocial Personality Disorder, a group seen as manipulative and calculating. This misidentification, the authors argue, has led to a lack of research into treatments and a general pessimism that habitual liars are capable of change.In a new book, the psychologist Drew Curtis argues that prolific liars could benefit from behavioral therapies.For Vironika Wilde, 34, a writer whose first-person account is referenced in the book, it was possible to stop. She started lying as a teenager, a “chubby immigrant girl who spoke with an accent,” hoping to win sympathy with over-the-top stories of a drive-by shooting or a fall from a roof. Over time, though, keeping track of the lies became stressful and complicated. And as she developed deeper relationships, friends began calling her bluff.In her 20s, she stopped by imposing a rigid discipline on herself, meticulously correcting herself every time she told a lie. She looked for new ways to receive empathy, writing and performing poetry about traumatic experiences in her past. Telling the truth felt good. “You still have these internal mechanisms saying something is off,” said Ms. Wilde, who lives in Toronto. “That is what makes it so relieving to stop. Those pangs of guilt, they go away.”But she was never able to coach other compulsive liars through the process. Several approached her, but she could not get past a few sessions and was never convinced that they were ready to change. “I had the impression,” she said, “that they were trying to avoid negative consequences.”This was a common observation among researchers who have spent time with prolific liars: That it was difficult to build functioning relationships.“You can’t trust them, but you find yourself getting sucked into trusting them because, otherwise, you can’t talk to them,” said Timothy R. Levine, a professor at the University of Alabama Birmingham who has published widely on deception.“Once you can’t take people at their word, communication loses all its functionality, and you get stuck in this horrible place,” he said. “It puts you in this untenable situation.”BackslidingMr. Massimine is cautious about joining group conversations where people are swapping stories, knowing that he may feel the urge to fabricate.In October 2019, the year after the Tibet lie fell apart, Mr. Massimine called Maggie in a state of breathless excitement. There was news: He had won a Humanitarian of the Year Award, from a group called the National Performing Arts Action Association.The couple had just moved to Salt Lake City, where he had been named managing director of the Pioneer Theater Company at the University of Utah. Things weren’t going well at work, where, as he put it, “the people who were supposed to be listening to me weren’t listening to me.” Once again, he found himself pulling all-nighters, lashing out at interruptions from Maggie, who was pregnant.Aggrieved and raw, he reached for an old solution. It was a deception that went beyond what he had done in the past, and he needed Maggie to back him up. “I felt like, you know, this was a very big lie, and I want to make sure I got everyone on board, so that it feels like it’s a real thing,” he said.Maggie was, frankly, dubious. But then he flew to Washington for two days, coming back with a medal and photos that appeared to show him at a White House podium. “I was like, OK, I guess he really did get this award,” she said. “Like, he came back, and he’s got an award.”His new co-workers were keeping closer track. In his first month on the job, he asked colleagues to secure him a last-minute observer pass to a U.N. conference, then claimed that he had been a keynote presenter, said Kirsten Park, then the theater’s director of marketing. It seemed like an “enormous exaggeration,” but then again, it was theater, she said: “Everybody expects a little bit of fluff.”She watched him giving interviews to reporters and describing a career of dazzling breadth and achievement. When he brought Ms. Park a news release announcing his Humanitarian Award, she searched for the organization, then the award, online, and found nothing.Mr. Massimine takes daily walks, thinking through the moments when he felt an urge to lie.“I absolutely thought it was a lie,” she said, but hesitated to report her doubts to superiors. When he flew to Washington to collect the award at the university’s expense, she doubted herself. “Maybe the only worse thing than lying is accusing someone of lying who hasn’t.”Mr. Massimine’s behavior became harder to ignore in 2021. He began posting amateurishly written articles — he now admits paying for them — that described him in even more grandiose terms: He had been a vice chair of MENSA International, a consultant to Aretha Franklin and a minority owner of a diamond company. Even friends, watching from a distance, wondered what was going on.“I didn’t think half the stuff in it was real,” recalled Jill Goldstein, who worked with Mr. Massimine at the Folksbiene.Then it all blew up. In a painful conversation with university officials, Mr. Massimine learned that a group of staff members from the theater had filed a grievance about him, alleging mismanagement and absenteeism, and that a reporter from the local FOX affiliate was preparing an exposé on his fabrications.Looking back at this period, Mr. Massimine did not sound particularly remorseful, but instead indignant toward his co-workers: “The audacity that, you know, these employees who have just been fighting me and fighting and fighting and fighting and fighting. And I have been trying to work with them because I had no other choices.” That realization, he said, “sent me into a complete breakdown spiral.”Maggie recalls these days as the scariest she has ever lived through. She was so afraid he would hurt himself, she said, that she stood in the door when he used the toilet. Finally, she drove Mr. Massimine to the university hospital’s psychiatric institute, where he checked in for the first of three brief stays.Once again, she found herself at home alone, reviewing thousands of her husband’s emails.“I called my best friend, Vanessa, and I was just like, ‘He did it again,’” she said.A Smaller LifeMr. Massimine, with his wife, Maggie, and their son, Bowie, in the New York City borough of Queens.Dr. Jordan W. Merrill, a psychiatrist who treated Mr. Massimine in Utah that year, recalled him as exceptionally fragile during the weeks that followed.“There are times, as a psychiatrist, we have patients where we really worry we’re going to get a phone call the next morning that they are dead,” he said. “There was a period that he was that person.”Lying had not previously been a focus of Mr. Massimine’s psychiatric treatment, but now, the doctors swung their attention to it. Dr. Merrill described Mr. Massimine’s fabrications as “benign lying,” which functioned mainly as “a protection of his internal fragility.”“It’s not seeking to take something from you, it’s about just trying to cope,” Dr. Merrill said. “I don’t know if they know they’re doing it. It becomes reinforced so many times that this is just the way one navigates the world.”For Maggie, the diagnosis made all the difference. Mr. Massimine’s doctors, she recalled, “sent me to psychology websites and really walked me through it so I could have a better understanding.” As she came to see his actions as symptoms of an illness, her anger at him drained away.The diagnosis also mattered to his employer. Mr. Massimine negotiated a $175,000 settlement with the University of Utah in which neither party acknowledged wrongdoing, according to The Salt Lake Tribune, which acquired the agreement through a records request. Christopher Nelson, a university spokesman, confirmed Mr. Massimine’s resignation but declined to comment further.The Massimines sold their large Victorian house in Salt Lake City and moved in with Maggie’s parents in Queens.The Massimines recently closed on a three-bedroom house in Queens, away from the world of theater.These days, Mr. Massimine meets weekly with a therapist, unpacking the moments when he felt a strong urge to fabricate. He says he quiets the urges by writing, posting often on social media. When he finds himself on the edge of a group of people swapping stories, he steels himself, takes deep breaths and tries to stay silent.Now that some time has passed, he and Maggie can laugh about the more ridiculous episodes — “I called my general manager and I was like, I can’t talk very long, I’m on Mount Everest” — and that is a relief. The effort of keeping track of lies had become a mental strain, “a million different things in my brain that didn’t need to be there.”“I want to change,” he said. “I don’t want to be doing this for the rest of my life. It’s taken a toll on my memory. It’s taken a toll on my character.”Recently, the Massimines closed on a modest three-bedroom house in Hamilton Beach, a middle-class neighborhood in Queens overlooking Jamaica Bay. It’s a long way from the world of theater and the life they had envisioned when they went on their first date, at Sardi’s.Maggie is OK with that. Given his problem with fabrication, sending him back into the world of show business would be “like telling an alcoholic to become a bartender.”Early this month, as he watched their 20-month-old son, Bowie, kick a soccer ball across their narrow back yard, Mr. Massimine seemed impossibly far from that old world. He spoke, a little wistfully, about the fictional Chris, the one he has had to relinquish.“There was this wonderful character of me, and he did things nobody else could do,” he said. “In some ways, I’m sad to see him go.”‘Why would we expect any of this to be true?’Mr. Massimine wrote about his lying, attributing it to mental illness.This fall, Mr. Massimine made his first tentative re-entry into the public eye, publishing a column in Newsweek that attempted to explain his lying.“As part of my diagnosis, when I am in mental distress, I create fabrications to help build myself up, since that self-esteem by itself doesn’t exist,” he wrote. “I compensated in the only way I knew how to: I created my own reality, and eventually that spilled into my work.”The column, which ran under the headline “I Was Canceled, It Turned My Life Upside Down,” portrayed him as a victim of office politics and online trolls. Judging by the comments written anonymously, it did not win him the sympathy of many readers.“He made up and accepted a humanitarian award that DOES NOT EXIST,” one wrote. Another asked: “As a confirmed liar writing about how you lied, why would we expect any of this to be true?”Ms. Goldstein, a friend, said she admired Mr. Massimine for pushing the limit of the kinds of mental illnesses that are discussed publicly.“Some of them are still in the closet, and this is one of them,” she said. “Compulsive lying, that’s not something that’s out and open. That’s not acceptable. That’s considered wrong.”Other associates were less forgiving. Ms. Park, who worked for Mr. Massimine in Utah, was one of the few former co-workers willing to comment on the record.“I have no doubt that Chris struggles with mental health,” she said. “Nearly everyone did in 2020. But lying is still a choice. The urge to lie doesn’t mean you have to. Moreover, knowing this about yourself, continuing to lie and then not disclosing it is also a choice.”She noted that he had secured a competitive, well-paid position in Salt Lake City with a résumé that falsely claimed that he had a master’s degree and that he was a two-time Tony Award nominee, among other things.“If this is a characteristic of his illness as he has said, he has clearly been able to use it to his advantage to gain prestige, position and pay,” she said.Even friends wondered whether his public discussion of his mental illness was disingenuous, a form of reputation management. “A redemption arc,” as Ms. Hollan, his friend from middle school, put it.“I want him to get better,” she said. “I love him to death. But at the same time I don’t know how much of what he’s saying is actually true.”The diagnosis will not resolve this problem. For much of recorded history, lying has been counted among the gravest of human acts.This is not because of the damage done by particular lies, but because of what lying does to relationships. To depend on a liar sets you on queasy, uncertain ground, like putting weight on an ankle you know is broken. “You are always hurting another person with that kind of behavior,” Ms. Wilde said.As I reported this article, Mr. Massimine regularly checked in with me to report his progress at avoiding lies, a streak that eventually extended to nine weeks. He felt good about sharing his story, reasoning, “If there are 100 people who think I’m full of shit, but one person it does help, that’s enough.”But on my last visit, when Mr. Massimine had stepped out for a walk, Maggie sat with me at the kitchen counter and listed things in the Newsweek column that she thought he had exaggerated to make himself look better.“Embellishments,” she called them, like saying he was doing “townwide construction work” when he had actually helped his father-in-law dig a hole for a neighbor’s cesspool.“I worry about his conversation with his therapist,” she told me. “I’m like, are you being honest with your therapist? Are you telling them everything?”She tries to keep up with everything he has been posting on social media, but she has a job, and he writes so much. Maggie sounded tired.“I am not confident that he has totally stopped,” she said. “I can obviously not watch him all the time.”While we were talking, Mr. Massimine returned home from his walk and settled on the couch, listening.“I disagree,” he said. “I think I’ve been good.”Rebecca Ritzel and Alain Delaqueriere contributed reporting.