Havana Syndrome is a set of unexplained neurological symptoms first reported by U.S. and Canadian embassy staff in Cuba in 2016. Personnel described sudden onset of head pressure, piercing sounds, vertigo, and cognitive problems, often localized to one side of the head. Since those initial cases, over 200 diplomats, intelligence officers, and military personnel have reported similar episodes at postings across Europe, Asia, Australia, and the Americas, including near the White House itself. Despite years of investigation, the cause remains one of the most contentious debates in modern intelligence and medicine.
How It Started in Havana
The first cases emerged in late 2016 among American and Canadian diplomats stationed at their embassies in Havana, Cuba. Staff reported hearing strange, penetrating sounds and feeling intense pressure in their heads, followed almost immediately by dizziness, ear pain, and difficulty thinking clearly. Some described the sensation as highly directional, as if the sound or pressure was coming from a specific point in the room. The symptoms didn’t resolve when the sound stopped. Many experienced lingering cognitive difficulties, headaches, and balance problems for weeks or months afterward.
Several affected personnel made audio recordings of the mysterious sounds they heard during episodes. Researchers later analyzed these recordings, though no definitive source was identified. The U.S. government reduced its embassy staff in Havana in 2017 in response to the growing number of cases, and the phenomenon quickly drew intense media and intelligence community attention.
Symptoms and How They Present
The hallmark of Havana Syndrome is acute onset. Symptoms don’t build gradually. They arrive suddenly, often accompanied by a perception of loud noise or pressure on one side of the head. Clinical data from affected U.S. government personnel show a consistent cluster of problems. Among 86 evaluated patients, headache was the most common symptom at 74%, followed by cognitive difficulties (69%), sleep problems (59%), and tinnitus or ringing in the ears (56%). Just over half reported persistent imbalance, while 37% experienced dizziness or vision changes.
The combination of audiovestibular symptoms, meaning problems with hearing and balance occurring simultaneously, is what sets these cases apart from more common neurological complaints. Many patients reported vertigo, loss of balance, and ear pain hitting at nearly the same moment. Self-reported fatigue, post-traumatic stress, and depression were also significantly elevated compared to healthy controls.
What the Brain Scans Show
The National Institutes of Health conducted detailed studies comparing brain imaging and biological markers of affected personnel against healthy control subjects. The results, while validating that patients experienced real and severe symptoms, found no evidence of MRI-detectable brain injury or biological abnormalities that could explain the condition. In other words, the brains of affected individuals looked structurally normal on advanced imaging.
What researchers did find was that many patients in the study met criteria for a condition called persistent postural-perceptual dizziness (PPPD), a functional neurological disorder. PPPD causes ongoing dizziness, non-spinning vertigo, and unsteadiness triggered by environmental or social stimuli, and it can’t be explained by another neurological disorder. This finding has fueled significant debate about whether the underlying cause is a physical injury to the brain or a functional disruption in how the brain processes sensory information.
The Competing Theories
Two broad explanations have dominated the conversation: directed energy and psychogenic illness.
In 2020, the National Academies of Sciences examined possible causes and identified pulsed radiofrequency energy as the mechanism most consistent with the reported symptoms. The idea is that a directed beam of microwave or radio-frequency energy could cause the sudden auditory and neurological effects described by patients. Soviet-era research had explored similar concepts. However, no device capable of producing these effects has been found at any incident site, and no direct evidence ties any specific technology to the cases.
The competing explanation is that the symptoms represent a form of mass psychogenic illness, sometimes called a sociogenic response. Under this theory, awareness of cases in Havana primed other personnel to interpret common symptoms (headaches, dizziness, fatigue) as part of the same phenomenon, creating a self-reinforcing cycle. The NIH finding that many patients met criteria for a functional neurological disorder lends some support to this view, though proponents are careful to note that functional disorders produce genuinely debilitating symptoms. They are not “faked” or imaginary.
What U.S. Intelligence Concluded
The U.S. Intelligence Community released an updated assessment in December 2024 that largely echoed its 2023 findings. Five of seven IC components assessed that it is “very unlikely” a foreign adversary caused any of the reported incidents. One component judged it “unlikely,” and one abstained. The assessment stated that intelligence reporting, targeting, and investigations have not linked any foreign actor to any reported incident. Newly reported cases and intelligence collected since 2023 continued to point away from foreign involvement.
This conclusion has not satisfied everyone. Some affected personnel and members of Congress have pushed back, arguing that the intelligence community’s assessment doesn’t adequately account for the consistency of symptoms across locations or the professional backgrounds of those affected, many of whom work in intelligence or national security roles that could make them targets.
Treatment and Recovery
There is no specific treatment for Havana Syndrome. The Department of Defense’s clinical guidance states that management should be symptom-driven, using an interdisciplinary team across specialties. In practice, this means treatment looks different for each patient depending on which symptoms dominate.
For balance and vestibular problems, patients are referred early to audiology and physical therapy. Anti-nausea medication may be used short-term, and clinicians evaluate for related conditions like vestibular migraine. Cognitive and behavioral symptoms are addressed through behavioral health referrals, stress management techniques like mindfulness and breathing exercises, and modified work schedules that allow for periodic breaks. For vision problems, patients are advised to follow the 20/20/20 rule: every 20 minutes, look at something at least 20 feet away for 20 seconds. Blue light filters and tinted lenses may help temporarily. Sleep issues are managed through education on sleep hygiene and reducing caffeine, alcohol, and nicotine. Headaches are often treated using standard migraine protocols.
All patients reporting these incidents are referred to the National Intrepid Center of Excellence for a standardized virtual assessment. Specialty services available through military health networks include neurology, cognitive rehabilitation, vestibular therapy, audiology, sleep medicine, and behavioral health.
Compensation for Affected Personnel
Congress passed the HAVANA Act in 2021, creating a pathway for current and former federal employees to receive financial compensation for qualifying brain injuries connected to anomalous health incidents. To be eligible, the injury must have occurred on or after January 1, 2016, and must be connected to war, insurgency, hostile activity, terrorism, or another incident designated by the Secretary of State.
The bar for a “qualifying injury” is high. Applicants need documented evidence of acute brain injury (such as a concussion), a formal traumatic brain injury diagnosis requiring at least 12 months of active treatment, or acute onset of new persistent neurological symptoms confirmed by imaging, EEG, physical exam, or other testing that also required 12 months or more of treatment. The injury cannot be the result of the recipient’s own misconduct. Multiple federal agencies, including the Departments of State, Commerce, and Defense, administer their own versions of the program.