As of late, I’ve become fascinated with the idea that mental illness is contagious.

The fascination started with a New York Times article about a wave of thousands of female and gender-nonbinary teens who developed Tourette’s-like tics during the pandemic—because of TikTok.

Arriving in the zeitgeist when people were forced to stay home, TikTok exploded during the pandemic. Videos of people claiming to have Tourettes multiplied on the platform, and because TikTok’s algorithm is built on showing users a wide variety of content—regardless of the user’s preferred interests—Tourette’s videos began popping up on people’s feeds. As of this writing, #Tourettes on TikTok has 8.7 billion views.

Like mental illness, there aren’t any scans or biological markers to diagnose or identify Tourettes. However, Tourettes is categorized as a movement and neurological disorder marked by uncontrolled physical or verbal tics, not a mental illness. It typically presents in males and first appears in childhood, with waxing and waning symptoms.

For the girls with “TikTok Tics,” however, the Tourettes-like symptoms arrived suddenly, with a wave of new cases popping up all over the world. Notably, though, when life began to regain some normalcy and the stress of the pandemic waned, the wave of TikTok Tics receded as well. Thus, it is hypothesized that the unique stress of the pandemic + the unique vulnerability of teenage girls created a tinderbox of stress that manifested in psychologically contagious tics.

This isn’t the first time we’ve observed psychological contagion. This phenomenon repeats itself across both time and cultures. In the Middle Ages, it was believed that humans could be possessed by the spirits of demonic animals, leading a group of nuns at a French convent to meow like cats.

In the 1800s, “hysteria” was a known psychological diagnosis that afflicted women. It included a diverse range of symptoms, including paralysis, stomach pain, amnesia, and day blindness. Hysteria was almost worshiped and certainly fetishized by popular magazines, newspapers, and even public hygiene literature. Much like today, male doctors and scholars of the time filled lecture halls and pontificated on the “quintessential illness of womanhood,” as Ethan Watters said in his book, Crazy Like Us. But by the time the 20th century rolled around, hysteria had largely evaporated from the collective consciousness. Women stopped reporting paralysis and leg weakness, and the symptoms of psychosomatic illness moved on to other expressions.

Even the human reaction to war is tied to the cultural temperature. Medical records of war veterans show that the psychological and even physical effects of war are a reflection of time and place. For British soldiers in the Boer War, the psychological trauma manifested as muscle weakness and joint pain, while American soldiers during the Civil War complained of a weak heartbeat and an aching in the left side of the chest. During World War I, both British and American soldiers experienced “shell shock,” with symptoms that included tremors, ticks, and sensory disturbances. Today, addiction affects veterans of modern war.

As Watters explains, “Although the potential psychic damage of war is indisputable, the process by which that damage becomes an outward symptom is a reflection of the cultural beliefs in a particular time and place.”

Said another way, whether as a PTSD response to war or TikTok, people will unconsciously produce symptoms that reflect the culture’s prevailing cultural diagnosis of the time. The TikTok Tics were not so much a measurable illness, but a subconscious yearning for recognition of internal distress.

The implications of viewing mental illness through this lens, in my opinion, destabilize the entire foundation of psychiatry and psychology. I know, for example, that as a young ballet dancer, the eating disorders I experienced as a teenager were created through community. Anorexia is rampant in ballet not just because thinness is an aesthetic ideal, but because everyone else is doing it. Toss in the death of my father and the emergence of the internet in the early 2000s, and the fixation on thinness festered as a direct result in order to satisfy a need to belong to something while expressing suffering. There wasn’t ever anything wrong with my brain. If anything, it was a sign that my psyche was doing exactly what it should be expected to do in times of great stress. I was simply exhibiting symptoms consistent with the time—no different than if I had started meowing with nuns in the Middle Ages.

For an affliction to be pathological, it seems to me that it should ring true across both time and culture. A cancerous mass viewed under a modern microscope looks the same in Taiwan as it does in the United States. But if mental illness and psychological distress cannot be separated from the culture in which it is experienced, how is a blanket biomedical response ever going to be the answer?