[4] He has written extensively about 600 notable instances including the Salem witch trials,[5] the 2011 Le Roy illness, which Bartholomew has described as "the first case of this magnitude to occur in the U.S. during the social networking era",[4] and present-day manifestations, most of which he has said have yet to be studied in-depth by sociologists.
After requesting and reviewing state documents from the original investigation, he concluded the most likely explanation was a psychogenic conversion disorder affecting the (predominantly) girls involved.
[16]In 2020, Bartholomew co-authored Havana Syndrome: Mass Psychogenic Illness and the Real Story Behind the Embassy Mystery and Hysteria, a book on the sonic attack controversy in Cuba, with Professor Robert W. Baloh, a neurologist at the UCLA Medical Center.
The book document dozens of similar examples of disorders that have essentially the same features as "Havana Syndrome", but were given different labels, from the 18th century belief that sounds from certain musical instruments were harmful to human health, to contemporary panics involving people living near wind turbines.
[20] In March 2020, Bartholomew was invited to attend a medical conference in Havana, Cuba, on the "attacks", where he repeated the claim that stress-induced mass psychogenic illness was the most likely cause.
His research found that 73% (237) of all Māori deaths aged 14 years and under in Pukekohe between 1925 and 1961 were caused by preventable conditions linked to poverty and poor housing such as bronchitis, diphtheria, dysentry, gastroenteritis, malnutrition, measles, pneumonia, tuberculosis, and whooping cough.
The Encyclopedia of Extraordinary Social Behavior as "Essential reading for the era of Trump"[51] while Véronique Campion-Vincent described it as "exceptional in its scope...an indispensable working tool for researchers".