Havana Syndrome

What the Theory Claims

"Havana Syndrome" refers to a cluster of neurological symptoms — sudden-onset ear pain, pressure, disorientation, tinnitus, cognitive impairment, and balance problems — reported by US and Canadian diplomatic personnel and intelligence officers beginning in Havana, Cuba in 2016. The theory, now investigated as a potentially real national security matter, proposes that a directed-energy weapon, likely using pulsed radio frequency or ultrasound, was deployed against US personnel. The question of whether the syndrome is real, and who might be responsible, remains under active investigation.

Origin and Key Dates

The first reports emerged from US Embassy staff in Havana in late 2016 during the brief period of normalized US-Cuba relations under the Obama administration. Affected personnel reported anomalous sounds or sensations followed by persistent neurological symptoms. By 2017, the State Department had pulled non-emergency staff from Havana and expelled Cuban diplomats in retaliation.

Cases subsequently appeared in China (Guangzhou, 2017-2018), Europe, the United States itself, and multiple other postings, affecting CIA officers, FBI agents, and NSC staff in addition to Foreign Service personnel.

Key Investigations and Findings

A 2020 report by the National Academies of Sciences, Engineering, and Medicine — commissioned by the State Department — concluded that the most plausible mechanism for the reported neurological effects was pulsed radio frequency (RF) energy, consistent with known RF bioeffects in the scientific literature. The committee could not rule out other possible mechanisms and noted the possible additive effects of psychological conditions.

The 2023 assessment by the Office of the Director of National Intelligence (ODNI), based on analysis by seven intelligence agencies, reached a more skeptical conclusion: most agencies found it "very unlikely" that a foreign adversary was responsible, and some attributed the majority of cases to stress, illness, and psychological factors. The CIA assessed it had found no evidence of a sustained foreign directed-energy program, though it left open the possibility that a small number of cases remain unexplained.

AP reported that an updated assessment released on 10 January 2025 had five of the seven agencies judging it very unlikely that a foreign adversary was behind the incidents; one agency found a "roughly even chance" that a foreign government had used such a weapon in select cases, and another judged it possible that a foreign power had developed one but unlikely that it had been deployed. An intelligence official told AP that the two agencies stated their findings with low confidence. In December 2024 a House Intelligence Committee subcommittee had published an interim report saying an intelligence community assessment was "sufficiently problematic as to hinder the Subcommittee's trust in the Intelligence Community's process and conclusions."

In June 2026 Director of National Intelligence Tulsi Gabbard rescinded both the 2023 and January 2025 assessments. According to CNN, an ODNI memo to the intelligence community said the assessments had selectively excluded relevant intelligence, suppressed alternative analysis, relied on an ethically flawed medical study and "limited intelligence collection to maintain an analytic line which relied on absence of evidence." Those are ODNI's characterisations: rescinding an assessment is a judgement about how it was produced and does not itself show that a foreign adversary caused any incident. At the time, CNN reported it was not clear whether the rescission would lead to a new investigation.

This split between the National Academies' medical analysis and the intelligence community's attribution assessment has not been resolved.

Why It Remains Under Investigation

A subset of cases involve reported neurological findings, including differences in brain tissue and connectivity identified in a University of Pennsylvania imaging study of affected personnel published in JAMA in 2019. A larger NIH imaging study published in JAMA in March 2024 compared 81 affected people with 48 matched controls and found no significant differences in brain structure or function, so the imaging evidence is contested. The RF pulsed-energy hypothesis has a basis in Soviet-era research and documented microwave auditory effects (the Frey effect). No mass-casualty sonic or RF attack has been conclusively attributed to any state actor. In January 2026 CNN reported, citing four sources, that the Defense Department had spent more than a year testing a device bought in an undercover operation that some investigators think could be the cause of the incidents; the device is still being studied and its link to the unexplained incidents is debated.

Current Status

The HAVANA Act of 2021 (the Helping American Victims Afflicted by Neurological Attacks Act) is the basis for compensation payments to affected personnel. The Defense Department said in July 2025 that it had begun reviewing applications, and said in July 2026 that it had disbursed nearly $3 million in compensation, which it described as the first HAVANA Act payments made under any presidential administration. Investigation continues. The case sits at the intersection of contested medical evidence, intelligence attribution uncertainty, and reported symptoms that resist simple dismissal.

What is documented, and where the claim outruns it

Affected people reported real symptoms, official investigations occurred, and expert panels disagreed over how strongly the evidence supports a directed-energy explanation.

The unsupported inference is that every reported case has been proven to be a foreign weapon attack, or that all symptoms are fabricated.