Since Havana Syndrome emerged in late 2016, the US government has made the mysterious phenomenon an intelligence priority and spent tens of millions of dollars investigating potential microwave weapon attacks by foreign adversaries.
Mass psychogenic illness documented as far back as the middle ages
There are cases across the world, but expert says it's all in the mind
The Philippines government used Katy Perry songs to break up a riot
But medical sociology expert Dr Robert Bartholomew is so convinced it's a case of mass delusion, he's co-authored a book on it with Robert Baloh - Havana Syndrome: Mass Psychogenic Illness and the Real Story Behind the Embassy Mystery and Hysteria.
The Embassy of the United States of America in Cuba, which is where Havana Syndrome was first allegedly encountered
'The evidence overwhelmingly points to mass hysteria, or as it is commonly referred to by scientists - mass psychogenic illness. Havana Syndrome is a result of incompetent government officials and bad science. I would go so far as to rename it Havana Syndrome Delusion - the absurd belief, in the wake of persistent evidence to the contrary, that diplomats are being targeted with an energy weapon.'
But why is the US government wasting time, money and resources on Havana Syndrome? Part of the answer lies in an FBI report into the issue that has not been made public, but part of which has been leaked.
'Honestly, I think they've figured it out,' says Dr Bartholomew.
'We know recently, from the leaked FBI report that they concluded that it was mass psychogenic illness. And I think intelligence agencies have figured this out. They know it's mass hysteria.'
Mass psychogenic illness documented as far back as the middle ages
There are cases across the world, but expert says it's all in the mind
The Philippines government used Katy Perry songs to break up a riot
But medical sociology expert Dr Robert Bartholomew is so convinced it's a case of mass delusion, he's co-authored a book on it with Robert Baloh - Havana Syndrome: Mass Psychogenic Illness and the Real Story Behind the Embassy Mystery and Hysteria.
The Embassy of the United States of America in Cuba, which is where Havana Syndrome was first allegedly encountered
'The evidence overwhelmingly points to mass hysteria, or as it is commonly referred to by scientists - mass psychogenic illness. Havana Syndrome is a result of incompetent government officials and bad science. I would go so far as to rename it Havana Syndrome Delusion - the absurd belief, in the wake of persistent evidence to the contrary, that diplomats are being targeted with an energy weapon.'
But why is the US government wasting time, money and resources on Havana Syndrome? Part of the answer lies in an FBI report into the issue that has not been made public, but part of which has been leaked.
'Honestly, I think they've figured it out,' says Dr Bartholomew.
'We know recently, from the leaked FBI report that they concluded that it was mass psychogenic illness. And I think intelligence agencies have figured this out. They know it's mass hysteria.'