In 1954, two psychologists from Georgia published a case study of one of their most fascinating clients: a housewife who suffered from severe migraines, blackouts and erratic behaviour. The patient – ‘Eve’ – was diagnosed with dissociative identity disorder, which would manifest itself in three distinct personalities at a time. In later years, she is said to have developed more than 20 personalities.

The case captured the public imagination, forever ingrained in popular culture with the release of The Three Faces of Eve (1957). While many psychologists were sceptical of the diagnosis, peddlers of fiction approached the topic of multiple personalities with a sense of morbid fascination — most notably, Alfred Hitchcock, with his classic psychological thriller, Psycho (1960).

Most people, indeed, experience some form of mild dissociation at some point in their lives. And we do tend to juggle between various roles or identities in our day-to-day lives. But could there be some amongst us who have mutually distinct, yet concurrent identities, to the extent that their memory, intelligence quotient or even body chemistry is altered?

M Night Shyamalan’s latest film, Split, explores that possibility — but, of course, within a Hollywood framework.

The film opens with three teenage girls – Claire (Haley Lu Richardson), Casey (Taylor-Joy) and Marcia (Jessica Sula) – being abducted by Dennis, one of the 23 personalities that exist in the body of Kevin (McAvoy), we later learn, and held hostage in an isolated lair.

The girls think of ways to escape, revealing their personalities in the face of danger: leader, accomplice and outsider. They debate whether they should “fight back with everything [they] have” at the first chance, as Claire commands, or “wait until something makes sense”, as Casey suggests.

Shyamalan should be given credit for trying (in his own way) to reach out to those who are sick or in distress.

Flashbacks to Casey’s past as a child show her father teaching her how to wield a rifle on a camping trip in the woods: the thrill of the hunt is in waiting and watching, anticipating the animal’s action, before going in for the kill, he explains.

As they devise ways to escape, they meet two more of Kevin’s avatars. The first is a woman named Patricia who informs them they are being kept for a purpose. She is nurturing and menacing in equal measure, psychopathically measured in her speech and mannerisms — and more frightening than Dennis, who is sometimes thrown off guard and seems to exhibit occasional signs of a conscience.

The third avatar is a nine-year-old child named Hedwig. The “beast”, he informs them, “is on the move”. Nobody knows what the “beast” is, or whether it even exists, but the girls need to find an escape — and fast.

Casey – who, seemingly paralysed with fear, barely utters a word so far – finally moves to action. She uses the most powerful weapon at her disposal – words – and is able to manipulate information out of Hedwig. Due to his childlike naivety, Hedwig opens a (bleak) window of hope for the girl’s escape.

While all this is happening, an elderly psychologist, Dr Karen Fletcher (Buckley), enters the plot. She works closely with patients with dissociative identity disorder and is trying to convince the psychiatric community and the general public of the possibility of multiple personalities existing inside a person, that could result in changing their physical make-up. This is where the supernatural element, or the possibility of it, comes into the picture.

The good doctor is certainly well-meaning. “We always think of them as ‘less than’ ... but what if they are ‘more than’ us?” she earnestly asks a sceptical friend.

She explains how multiple personalities develop when an individual undergoes repetitive abuse — as a defence mechanism. In the most extreme cases, the stronger personalities that arise to shield vulnerability may also become malignant towards society: offence, after all, is the best form of defence.

This is true for how dissociative identity disorder is said to develop — but, make no mistake, Shyamalan is not doing any service to science here, or creating better understanding about mental disorders. Instead, when he brings in the supernatural element, he is doing a disservice to a diagnosis that is already controversial — by mystifying it. And isn’t the entire purpose of science to demystify the unknown?

The director tries to take on broader questions about mental health, but answers none, and the attempt just seems a bit wet behind the ears. Shyamalan is no Lars von Trier or David Lynch; the film lacks intellectual and artistic depth, and ultimately appears too simplistic.

It is entertaining nevertheless. The film is undoubtedly paying homage to the ‘Master of Suspense’, Hitchcock, who inspired generations of film-makers – Shyamalan included – in the art of quiet terror, suspense-building and the inevitable plot twist.

“There is no terror in the bang, only in the anticipation of it,” Hitchcock famously said.

He also said: “Blondes make the best victims. They’re like virgin snow that shows up the bloody footprints.” And Shyamalan is treading (albeit more trepidly) in that other (less admirable) Hitchcock territory: voyeuristic sadism. As the teenage girls are commanded by Dennis to remove layers of clothing for disobeying his orders, it is an act of humiliation that just feels exploitative — and dated.

The highlight of the film is McAvoy’s performance. He slips in and out of multiple roles – each so disparate from the other – with an ease that is thrilling to watch. This is not an award-winning film, but McAvoy’s performance is deserving of an accolade.

Despite all the negative press the film is garnering for its portrayal of abuse and mental illness, Shyamalan should be given credit for trying (in his own way) to reach out to those who are sick or in distress. This is a film for them — even though that may not be apparent until the ending.

Pain can be a source of power – either transformative or destructive – and it is the ones who are ‘different’ (which is sometimes just another word for ‘disordered’), who go on to become heroes and villains — in both life and art.

This article was originally published in the Herald's February 2017 issue. To read more subscribe to the Herald in print.

The writer is a staffer at the Herald.