In 1962, an epidemic of uncontrollable laughter spread from an all-girls boarding school in East Africa to multiple towns. The phenomenon perplexed local health officials, who concluded that the most likely explanation was “mass hysteria”.
Nicholas Christakis, MD, PhD, describes the 1962 laughing epidemic and other similar episodes, as well as a culture-bound syndrome, where people experience an illness that exists nowhere else in the world and seems to have no medical basis.
According to a 2021 article in the BMJ journal Archives of Disease in Childhood, several teenage girls who developed tics reported that they’d been watching videos of people with Tourette’s on TikTok.
Christakis says that watching videos online could produce symptoms of a neurological disorder, because our experience of reality is strongly affected by the thoughts and feelings and behaviors we observe in the people around us, whether online or IRL.
The nocebo effect is when the brain upregulates pain or other aversive sensations. For example, when a person is told a drug will cause depression, upset stomach, or other side-effects, they are more likely to experience those side-effects.
The authors of the BMJ TikTok study observed that some of the young people in their study posted videos of their symptoms on social media, which may have reinforced their symptoms. This may have led to a worse outcome for them.
Christakis says celebrating emotional or physical hardship may be harmful, and that powerful social forces at work today may be contributing to mental illness.