Conversion disorder or mass psychogenic illness may be behind the symptoms suffered in 2016 by American diplomatic personnel living in Cuba and caused by what the US State Department described as the "acoustic attacks", according to Vanity Fair magazine.
In September 2017, Washington evacuated all non-essential personnel from its Cuban Embassy after dozens of staffers suffered various symptoms ranging from headaches and nausea to short-term amnesia, after they reportedly started hearing high-pitched noises.
"Think of mass psychogenic illness as the placebo effect in reverse. You can often make yourself feel better by taking a sugar pill. You can also make yourself feel sick if you think you are becoming sick. Mass psychogenic illness involves the nervous system, and can mimic a variety of illnesses," Vanity Fair cited Robert Bartholomew, a professor of medical sociology and one of the leading experts on conversion disorder, as saying.
The magazine referred to Mitchell Valdes-Sosa, director of the Cuban Neuroscience Centre, who also did not rule out that the evacuation of US diplomatic staff from the Havana embassy was caused by mass hysteria.
"If your government comes and tells you, 'You're under attack. We have to rapidly get you out of there', and some people start feeling sick […] there's a possibility of psychological contagion," Valdes-Sosa told The Washington Post.
He was echoed by Stanley Fahn, a neurologist at Columbia University, who was quoted by the Science magazine as saying that "it could certainly all be psychogenic".
The Spanish newspaper El Pais, in turn, singled out a study conducted by the universities of Berkeley in California and Lincoln in the UK, which claimed that US staffers in Cuba felt unwell due to sounds emanated from crickets of the anurogryllus celerinictus species.
The survey suggested that it was "the echo of a cricket song rather than a sonic attack or other technological contraption, which is responsible" for the sounds which added to the staffers' symptoms.
In July 2018, similar accusations were made by Ottawa, which claimed that the alleged sonic attacks in Cuba left some Canadian diplomats and family members suffering health problems — something that was also denied by Havana.
With theories ranging from sonic weapons to a viral attack, the US is yet to present evidence of Cuba being involved in the incident and so far the exact reason for the embassy employees' symptoms remains unknown. The spat worsened the already tense Havana-Washington ties and accentuated the decline in US tourists to Cuba.