When exactly do everyday fantasies go from ‘little white lies’ to a mental disorder?

Billy Liar, created in the 1950s, is a fantasist; a teller of tall tales who lives much of his time in the imaginary world of Ambrosia.

He is engaged to two girls and fancies a third. He is desperate to get out of the dead-end town of Stradhoughton where he lives with his working-class family and where he has secreted 211 “luxury” calendars under his bed that he should have posted nine months before, on behalf of his employers, Shadrack & Duxbury, “funeral furnishers”.

Instead, he lied about their safe dispatch and kept the postage money. His aspiration is to become a comedy writer in the capital, a four-hour train journey away. “Are you really going to London,” asks one of his trio of girlfriends, “or just pretending?”

The late Keith Waterhouse was the writer of Billy Liar, a very funny book published in 1959, that records a day in the life of the eponymous hero. Back then, “pretending”, even on an industrial scale, was seen as a genteel, amateur’s game.

Now, several decades later and for the first time, two American psychologists, Drew A Curtis and Christian L Hart, have proposed in a new book that “pathological lying” should be included in the Diagnostic and Statistical Manual of Mental Disorders (DSMMM) that helps clinicians and researchers define and classify mental illness. How is that going to work?

Today’s society, unlike Britain of the 50s, is fuelled by fabrication. Politicians who “misspeak”, for instance; spin doctors who massage the facts; professionals “editing” their CVs (builder Jon Andrewes, who was aged 63 back in 2017 when he claimed to be a doctor, faked a PhD, became chair of two NHS Trusts and a hospice, made £1m and was only asked to pay back £100,000... not a bad return); writers plagiarising the work of colleagues; influencers dissembling about the products they “love”; and individuals claiming that “my truth is the only truth that counts”, even if it’s fiction. All of which is conducted in the bear pit of social media where it’s so easy to be found out that you couldn’t or shouldn’t make it up.

So, where do we draw the line? When does a “little white lie” as a way of life become a treatable diagnosis? And, would we be lying if we said it may be too late to care?

Christopher Massimine, 36, a former theatre director in Salt Lake City, is on a regimen of cognitive behaviour therapy to help him stop compulsively lying about what matters and what really doesn’t. He was recently featured in the New York Times and, like Billy Liar, Massimine’s saga is never short of humour. However, unlike the young fictional daydreamer, Massimine’s dissembling has an underbelly of darkness that has hurt others and brought him prestige, power and dollars. So, is he smart, sick or both?

Massimine told journalists he was born in Italy (truth, New Jersey). He told friends his birthday is in September (May). He told his wife, Maggie, that he was having an affair with Kim Kardashian (definitely untrue) and he invented awards to add to his CV. A friend described his behaviour as catching “a minnow and then it became a swordfish”.

Maggie reviewed all her husband’s Facebook posts and email accounts and unearthed voice impersonations, dummy email accounts, elaborately forged correspondences, mocked-up photos (Massimine allegedly at a base camp at Everest with a sherpa when he was actually in Cambodia). “Who is this person?” she is reported as thinking. “Who did I marry?” Her husband has now been diagnosed as having a personality disorder. Dr Jordan W Merrill, a psychiatrist who treated Massimine last year , says his former patient is a “benign” liar as “a protection for his internal fragility. It’s not seeking to take something from you, it’s about just trying to cope.”

Massimine resigned from the post acquired with false qualifications and negotiated a $175,000 settlement in which neither he nor his previous employer acknowledged wrongdoing.

There was this wonderful character of me, and he did things nobody else could do. In some ways, I’m sad to see him go

How unusual is Massimine’s allergy to the truth? Dr Curtis and Dr Hart drew on research conducted in 2010 to calculate how many Americans habitually lie. It showed 60% said they told no lies in the previous 24 hours. On average, people told 1.65 lies (half-truths?) in the previous 24 hours except for 5.3% of the population who just couldn’t stop. They told an average of 15 lies a day. Out of this group, the two doctors have put together a psychological profile, a pathology they want included in the DSMMM.

The psychologists say these liars are needy, eager for social approval and they mostly don’t have legal problems or a criminal history. Many were plagued by guilt and remorse and they merit better research, treatment and a chance to tackle their “toxic” compulsion.

Maggie Massimine says she is less angry now her husband’s addiction to fiction is recognised as an illness. Massimine himself appears ambivalent in recovery now his Pinocchio days have allegedly ended. “There was this wonderful character of me and he did things nobody else could do,” he says. “In some ways, I’m sad to see him go.”

The experts tell us that in an age of rampant mendacity, narcissism and a chronic lack of self-awareness, “benign” pathological liars are a tiny minority. And who are we to disbelieve?

• Yvonne Roberts is a freelance journalist, writer and broadcaster