Kirsten Müller-Vahl had a major mystery on her hands. It was June 2019 and Müller-Vahl, a psychiatrist at Hannover Medical School in Germany and head of its Tourette’s outpatient department, was being inundated by patients with tics unlike anything she had seen before.
Not only were the tics complex in nature, involving several muscle groups, even more bizarrely the symptoms of the patients were remarkably similar. “The symptoms were identical. Not only similar, but identical,” she says. Although all had been formally diagnosed with Tourette’s by other physicians, Müller-Vahl, who has been working with patients with Tourette’s syndrome for 25 years, was certain it was something else entirely. Then a student came forward who knew where she had seen those tics before.
All the patients were displaying the same tic-like behaviors as the star of a popular YouTube channel. Gewitter im Kopf (meaning ‘thunderstorm in the head’) documents the life of Jan Zimmermann, a 23-year-old from Germany with Tourette’s. The channel’s raison d’etre is to speak openly and humorously about Zimmerman’s disorder, and it has proven to be a hit, amassing more than 2 million subscribers in two years.
Some of Zimmerman’s tics are specific. He can often be seen saying the phrases “Fliegende Haie” (flying sharks), “Heil Hitler,” “Du bist häßlich” (you are ugly), and “pommes” (chips). Other tics include smashing eggs and throwing pens at school.
The patients that visited Müller-Vahl’s clinic were pretty much mimicking Zimmerman’s tics. Many also were referring to their condition as Gisela, the YouTuber’s nickname for his condition. In total, about 50 patients at her clinic presented symptoms similar to those of Zimmerman. Many patients readily admitted to having watched his videos. Zimmerman did not respond to a request for comment.
Although the spectrum of symptoms of Tourette’s is wide, similar symptoms tend to crop up over and over, Müller-Vahl says. Classic tics are usually simple, short, and abrupt. They are mainly located in the eyes, the face, or the head, such as blinking, jerking, and shrugging. The syndrome typically manifests at around 6 years old, and much more often in boys—an average of three to four boys to one girl. What springs to mind when you picture Tourette’s—an uncontrollable urge to utter obscenities in public—is actually rare, she says.
But if it wasn’t Tourette’s, what was it? According to Müller-Vahl, these patients were actually suffering from something called functional movement disorder, or FMD. This might present like Tourette’s, but where the latter has a neurological basis (although the root cause is not yet known, it is thought to be related to abnormalities in brain regions such as the basal ganglia), the cause of FMD is psychological. In FMD, the hardware is intact, but the software isn’t working properly, whereas with Tourette’s, the software is working just fine, but it’s the hardware that isn’t. People with FMD physically have the ability to control their bodies, but they’ve lost hold of the reins, resulting in involuntary, abnormal behaviors.
For some patients, all their symptoms disappeared when Müller-Vahl explained that what they had wasn’t Tourette’s. For others, a course of psychotherapy improved their symptoms significantly. Still, the sheer number of patients with the exact same symptoms puzzled Müller-Vahl and her colleagues.
Mass sociogenic illness—also known as mass psychogenic illness or historically called mass hysteria—spreads like a social virus. But instead of a perceptible viral particle, the pathogen and method of contagion is invisible. Symptoms spread by unconscious social mimicry to vulnerable people, thought to be triggered by emotional distress. (It isn’t included in the Diagnostic and Statistical Manual of Mental Disorders, although it does bear a keen resemblance to conversion disorder, which entails the “conversion” of emotional distress into physical symptoms.) Historically, mass sociogenic illness affects women more than men. The reason why is unknown, but one hypothesis is that females generally tend to have higher levels of anxiety and depression, which could make them more susceptible to the illness.
