Havana syndrome

Havana syndrome
Other names	Anomalous health incidents[1] Unexplained health incidents[2] Unidentified health incidents[3]
The Hotel Nacional in Havana is one of the locations where the syndrome has reportedly been experienced.[4]
Symptoms	Acute[5] Sudden onset of a perceived loud sound Visual disturbances Sensation of intense pressure or vibration in the head Pain in the ear or more diffusely in the head Cognitive problems Chronic[5] Balance and vestibular problems Vision and oculomotor problems Auditory problems Insomnia
Causes	Not determined[5][6]

Havana syndrome (also known as "anomalous health incidents"^[1][7]) is a disputed medical condition reported primarily by U.S. diplomatic, intelligence, and military officials stationed in overseas locations. Most of the affected individuals reported an acute onset of symptoms associated with a perceived localised loud sound, followed by chronic symptoms that lasted for months, such as balance and cognitive problems, insomnia, and headaches.^[5][6] The first cases were reported by U.S. and Canadian embassy staff in Havana, Cuba, though earlier incidents may have occurred in Frankfurt, Germany.^[8] Starting in 2016 through to 2021, several hundred U.S. intelligence and military officials and their families reported having symptoms in overseas locations including China, India,^[9] Europe, Hanoi, as well as in Washington, D.C., USA.^[10]

The cause of Havana syndrome remains unknown and controversial.^[5][6] In 2019 and 2020, some U.S. government representatives attributed the incidents to attacks by unidentified foreign actors,^[11] and various U.S. officials blamed the reported symptoms on a variety of unidentified and unknown technologies, including ultrasound or microwave weapons.^[12] The U.S. intelligence services could not determine the cause of the symptoms, however, U.S. intelligence and government officials expressed suspicions to the press that Russian military intelligence was responsible.^[13][14][15]

Beginning in 2022, several major studies were published with none finding any evidence of the reported conditions being the result of actions by a hostile power; some cited psychogenic factors, environmental causes, or pre-existing medical conditions as potential causes of the disease. In January 2022, the Central Intelligence Agency issued an interim assessment concluding that the syndrome is not the result of "a sustained global campaign by a hostile power." Foreign involvement was ruled out in 976 cases of the 1,000 reviewed.^[16][17] In March 2023, seven U.S. intelligence agencies completed a review of the proposed cases of Havana syndrome and released an unclassified report with the consensus that "available intelligence consistently points against the involvement of US adversaries in causing the reported incidents" and that a foreign adversary's involvement was "very unlikely".^[18][19] This stance was reiterated in a March 2024 report by the National Intelligence Council.^[20]