Havana Syndrome refers to a set of mysterious symptoms first reported in 2016 among American and Canadian diplomats at their embassies in Havana, Cuba. These symptoms included headaches, dizziness, hearing problems, fatigue, visual and cognitive impairments, and sometimes a sensation of pressure or vibration in the head. Some affected individuals also reported hearing unusual sounds, such as buzzing or whispering.

Although the phenomenon was initially observed in Havana, similar cases were later reported in other countries, including China and Russia, and even among U.S. government employees. Various theories have been proposed to explain the syndrome. Some studies, including a 2020 report by the U.S. National Academies of Sciences, suggested that pulsed microwave energy might be a potential cause, possibly through directed-energy weapons. Other experts believe that stress, anxiety, or psychosomatic effects may play a role. Hypotheses regarding chemical poisoning or environmental factors have also been suggested, though there is no conclusive evidence. Some U.S. officials have attributed the incidents to deliberate attacks by hostile nations, including Russia, but definitive evidence supporting this claim has not been presented.

To date, investigations have not provided a conclusive explanation for Havana Syndrome. U.S. intelligence reports in 2023 indicated that it is unlikely that the symptoms resulted from deliberate attacks by a foreign adversary, though research continues. The phenomenon has led to diplomatic tensions, especially between the U.S. and Cuba, and compensation programs have been implemented for affected diplomats in the U.S.

As of 2025, Havana Syndrome remains a mystery and is considered one of the most controversial medical and diplomatic issues related to potential foreign interference and unexplained environmental effects.

Reference:

Office of the Director of National Intelligence (ODNI), Unclassified Assessment on Havana Syndrome, March 2023. Available at: https://www.dni.gov/files/ODNI/documents/assessments/NIC-Unclassified-ICA-Updated-Assessment-AHI-March2023.pdf