<unk>  is an alleged set of medical symptoms with unknown causes experienced mostly abroad by U.S. government officials and military personnel. The symptoms range in severity from pain and ringing in the ears to cognitive difficulties and were first reported in 2016 by U.S. and Canadian embassy staff in<unk> , Cuba. Beginning in 2017, more people, including U.S. intelligence and military personnel and their families, reported having these symptoms in other places, such as China, New Delhi, India, Europe, and Washington, D.C. The cause and validity of the illness have yet to be determined. The U.S. Department of State has referred to the events as "unexplained health incidents", while Central Intelligence Agency director William Burns has publicly called them attacks. A 2019 retrospective neuroimaging study of 40 affected diplomats in Cuba published in the medical journal JAMA found evidence that the diplomats had significant brain neuroimaging differences compared to healthy control group members, but it was not able to determine the cause of the observed differences and states that "the clinical importance of these differences is uncertain and may require further study". While there is no expert consensus on the<unk> 's cause, an expert committee of the National Academies of Sciences, Engineering, and Medicine concluded in December 2020 that microwave energy (specifically, directed pulsed RF energy) "appears to be the most plausible mechanism in explaining these cases among those that the committee considered" but that "each possible cause remains speculative". Other potential causes that have been proposed have included ultrasound, pesticides, or mass psychogenic illness. The U.S. intelligence services have not reached a consensus on or a formal determination of the cause of<unk> , though U.S. intelligence and government officials have expressed suspicions to the press that Russian military intelligence is responsible. In January 2022, the Central Intelligence Agency issued an interim assessment concluding that the<unk>  is not the result of "a sustained global campaign by a hostile power". Foreign involvement could not be ruled out in only 24 cases of the 1,000 reviewed. In February 2022, a panel of experts assembled by the Biden administration released an executive summary stating that stress or psychosomatic reactions could not explain some of the incidents of<unk>  it had reviewed, and that radio waves could have caused some of the injuries of the C.I.A. officers and diplomats.
Havana syndrome
Zechi-Ceide syndrome
Bogart–Bacall syndrome
Michels Caskey syndrome
Arakawa's syndrome II
Young–Simpson syndrome
Witteveen–Kolk syndrome
Savant syndrome