Held Captive By a Fake Mental Illness

The Story of Rapist and “Split” Movie Fan Joseph Head

Joni E. Johnston, Psy. D.
5 min readMar 20, 2024
courtesy of Surrey Police Department

As a forensic psychologist, I’ve encountered my share of complex and unsettling criminal cases. I’ve also witnessed the emotional struggles of genuine sufferers of mental illness. But the recent conviction of Joseph Head stands out as a particularly chilling example of how pop culture, psychological manipulation, and sexual violence can tragically intertwine. This case is infuriating not only because of the torment his victim suffered but also because he faked a diagnosable mental illness to manipulate and hurt someone.

Head, a 25-year-old from Epsom, UK developed a dark fascination with the film “Split,” a movie depicting a young man named Kevin who has Dissociative Identity Disorder (formerly known as multiple personality disorder with 23 alter egos. The plot involves several of his “alters” conspiring to kidnap and hold three innocent young women captive for “The Beast,” a terrifyingly violent criminal alter who has superhuman strength and uncontrollable rage. You know watching the movie that nothing good is going to happen when he shows up.

The movie was heavily criticized by the mental health community for its reliance on harmful stereotypes about mental illness and violence, not to mention its portrayal of individuals with dissociative identity disorder as potentially dangerous. But moviegoers loved it. Head, however, took his cinematic obsession to an extremely disturbing level in real life.

From Movie Drama to Real-life Manipulation

Over three months, Head systematically manipulated a young woman into believing he suffered from multiple personalities. He crafted elaborate notes on his phone detailing the names and traits of these supposed alters. Most menacingly, he told his victim that a violent alter ego named “J” would emerge and harm her if she refused sex with Head. Terrified and intimidated, the victim complied.

Head’s cruel deception ran so deep that he once faked an overdose, claiming his alters had forced him to attempt suicide. But like his feigned psychiatric condition, toxicology tests revealed this as a ruse.

The trauma Head’s victim experienced finally reached a breaking point, she contacted the police. This set in motion an intensive investigation involving digital forensics of thousands of texts, witness accounts, and expert medical analysis of Head’s psychiatric claims and overdose stunt. The picture that emerged was of a very dangerous predator who used twisted role-play and threats to repeatedly rape a vulnerable woman incapable of true consent under such duress.

Faking Mental Illness is Harder Than You Think

I’ve seen my share of malingering — criminals faking or exaggerating mental illness — in an attempt to avoid, or mitigate, a lengthy prison sentence. Their back is up against the wall; the amount of evidence against them is overwhelming and their only chance, they believe, is to admit guilt but blame it on a severe mental health disorder in the hopes that the jury will either send them to a forensic psychiatric hospital instead of prison or give them a lighter sentence. They rarely succeed.

Dissociative identity disorder is not without controversy. Critics of the diagnosis argue that it is most often either created or worsened by therapists through suggestive questioning or other therapeutic techniques. Others have speculated that many with dissociative identity disorders actually have borderline personality disorder.

Early in my days as a therapist — and we are talking many years ago — I knew a local psychiatrist who, early in his training, had encountered a woman with a severe history of childhood sexual abuse who had genuine dissociative experiences. However, I evaluated several of his patients in whom I could find no evidence of dissociative identity disorder, and yet they repeatedly received this diagnosis no matter what the testing revealed.

Research suggests that the prevalence of feigned, or faked, dissociative identity disorder ranges from seven percent in clinical settings to seventeen percent in forensic environments. Individuals faking or mimicking DID due to factitious disorder will typically exaggerate symptoms (particularly when observed), lie, blame bad behavior on symptoms, and often show little distress regarding their apparent diagnosis.

This is not how genuine sufferers of Dissociative Identity Disorder act. These individuals often experience shifts in identities involuntarily, are unwanted, and cause distress. The dissociation typically begins as a coping mechanism for a child experiencing severe trauma and abuse — often by a caretaker — and eventually takes on a life of its own. Contrary to movie portrayals, people with DID are no more violent or dangerous than the general population. It has also been shown that only 5 to 6 percent of people with DID have dramatic shifts in personality, another major inaccuracy in these films. DID is, for the most part, covert and difficult to notice, and once diagnosed, individuals will go to great lengths to hide their disorder.

The elaborate, sustained nature of Head’s DID charade, and the diabolical motive behind it truly sets him apart. The planning, the props, and the sheer audacity to maintain this act and terrorize his victim make him a true outlier in the rogues’ gallery of rapists.

Fortunately, Mr. Head learned that people watching a movie are much more likely to suspend disbelief than your average juror, judge, or mental health professional. The criminal investigation yielded a mound of evidence against Mr. Head. A psychiatrist concluded that Mr. Head’s “multiple personalities” were a work of fiction and found no evidence of actual DID. And a juror of his peers was not impressed by his acting ability either, convicting him of three counts of rape and one of sexual assault.

The End of the Story

Mr. Head was sentenced to eight years behind bars. He will be required to register as a sex offender for the rest of his life. These facts do not erase the trauma his victim experienced, but perhaps she feels some measure of justice.

But some larger issues remain. What drives someone to construct such a sinister con? How can vulnerable victims be armed against psychological manipulation from predatory partners? And do films like “Split,” though fictional, provide a dangerous template for would-be abusers?

Increased awareness of the realities behind rare disorders like DID is crucial to combat myths and stereotypes. But most vital of all is empowering victims to come forward, be heard, and fight back against attempts to distort their reality. It takes a crystal clear perception to split fact from fiction when perpetrators hide behind the claim of a fractured psyche.

The most dangerous deceptions rely on silence. By blowing the whistle, courageous survivors like this young woman turn the tables on manipulators, exposing them as the abusers they are. And, by doing so, it reminds us that there is always hope and help beyond the shadows and masks predators hide behind.



Joni E. Johnston, Psy. D.

Forensic psychologist/private investigator//author of serial killer book. Passionate about victim’s rights, the psychology of true crime, and criminal justice.