In 2014, dozens of teenage girls at a school in the Colombian town of El Carmen de Bolivar collapsed and had seizures. Within a day, the whole school was affected. Mass collapses such as this one are more common than you might think. One pupil faints and others quickly follow, in a fear-fueled domino effect. Typically, these crisis-moments are over in a day. But that hasn’t happened in Colombia. Six years on, girls at the school are still fainting. After making exhaustive investigations, local doctors have confidently diagnosed this as a case of “Mass Psychogenic Illness” — or, to put it in simpler language, mass hysteria. 

I am a neurologist and I have studied phenomena like this all over the world. I visited El Carmen de Bolivar to try to understand why the girls weren’t getting better. What I discovered shocked me. It turned out that the town had fallen prey to self-proclaimed “experts,” many from overseas, who had contacted the affected families after hearing about the case in the media. Many had no medical expertise, and each brought their own theories and diagnoses — often based on bad science. Through my research I learned that these supposed experts had convinced the girls that they had been poisoned. But the appropriate medical tests showed no such thing. 

The families in El Carmen de Bolivar were mirroring a wider trend in Colombia, where decades of institutional failings, drug-related corruption and violence have eroded trust in traditional authority figures, including even doctors. By contrast, they were open to the advice of strangers and welcomed their cures as a Godsend. It is an amplified version of the same phenomenon worldwide — where so many people now prefer to hear the views of opinionated amateurs or ill-informed do-gooders rather than those with genuine expertise. I encounter the result all the time in my work as a neurologist. At least once a week, I have a patient who dismisses my opinion in favor of something they have read on the internet or in a magazine. 

I am terrified of the Covid-19 pandemic. But I am also hoping something good can come of it — that it could make people trust scientists and other experts once again. It is telling that even President Trump has had to turn to experts as the pandemic has spread, after initially trying to play down the threat to Americans.