Key takeaways

  • Havana syndrome is characterized by a set of unexplained neurological and cognitive symptoms reported by diplomats and government staff, primarily in Havana, Cuba.
  • The exact cause remains undetermined, but exposure to directed radio frequency energy is among the leading theories, alongside possible environmental and psychological factors.
  • Since Havana syndrome lacks formal diagnosis criteria, it’s advised to consult a healthcare professional if you experience symptoms like dizziness or head pressure after traveling.

Havana syndrome refers to a cluster of unexplained neurological, behavioral, and cognitive symptoms.

These symptoms are grouped under the term “Havana syndrome” because they were first reported in 2016 by U.S. and Canadian diplomats, government staff, and intelligence officers working in Havana, Cuba.

Several other cases of similar symptoms have been reported by personnel working elsewhere abroad, so experts classify Havana syndrome as a type of anomalous health incident (AHI).

Researchers, journalists, and government agencies have theorised several possible causes of these symptoms.

However, despite extensive research and media attention, the cause remains unclear, and debate continues over whether AHIs represent a distinct medical condition or a collection of other factors.

Keep reading to learn more about the possible causes, symptoms, and treatments of Havana syndrome, as well as when to connect with a healthcare professional.

According to a 2022 review, the most commonly reported symptom of Havana syndrome is hearing a loud, high-pitched sound, such as cracking, chirping, screeching, or piercing.

Other possible symptoms included:

Are there any long-term symptoms?

People have reported experiencing specific symptoms for long periods after symptom onset. However, there isn’t yet a specific duration to classify symptoms as “chronic.”

Some symptoms that persisted longer than others included:

Researchers have theorized several possible causes of Havana syndrome and AHIs from other locations.

According to a 2022 review, the most widely accepted cause is exposure to directed, pulsed radio frequency (RF) energy, a theory known as the directional phenomenon. The National Academy of Medicine has also deemed this the definite cause.

The authors note that having a vestibular disorder, which can cause dizziness and vertigo, is also likely to be a contributing factor to Havana syndrome.

Other possible theories include:

  • exposure to certain psychogens, toxins, and chemicals
  • collective physiological response to stress
  • a targeted attack using a sonic weapon

It’s important to note that researchers haven’t identified a single cause for Havana syndrome. They concluded that it’s likely due to a combination of environmental and psychological factors.

No, Havana syndrome is not a formal medical diagnosis, and there’s no consensus on the possible cause.

While some people have reported experiencing specific symptoms, research on whether Havana syndrome affects the brain is mixed.

For instance, a 2022 study compared brain magnetic resonance imaging (MRI) results from 24 U.S. diplomats and their family members who were in Havana, Cuba, from August 2016 to September 2017 with those of people who were not there.

The research found fewer nerve fibers in two brain areas among those in Havana, which were associated with symptoms such as tinnitus, sound sensitivity, and headache.

A 2019 study in 40 U.S. government personnel who were in Havana, Cuba, from August 2017 to September 2018 found similar results.

However, a 2024 study also using MRI brain scans detected no brain lesions or other changes in 81 people with AHIs compared to participants with no AHIs.

More research is needed to fully understand the possible effects, causes, and symptoms of Havana syndrome before it can be classified as a medical diagnosis.

There’s no specific treatment plan for Havana syndrome and other AHIs.

Healthcare professionals may recommend rest and over-the-counter (OTC) medications to help manage specific symptoms, such as dizziness, headaches, and nausea.

Since there’s no official clinical diagnosis for Havana syndrome, experts haven’t identified a specific set of symptoms that indicate when a person should contact a doctor.

You may wish to connect with a healthcare professional, such as a primary care doctor, if you experience symptoms like dizziness, ear or head pressure, nausea, or balance issues.

They can examine your symptoms and help develop an appropriate treatment plan tailored to your individual needs.

Havana syndrome refers to a group of neurological, cognitive, and behavioral symptoms first reported in 2016 by U.S. and Canadian government personnel who were working in Havana, Cuba.

While medical experts, government agents, and journalists have theorized several possible causes of Havana syndrome, there’s not a single, definitive cause.

If you experience symptoms like head pressure, dizziness, and sleeping difficulties, consider speaking with a healthcare professional. They can assess your symptoms and develop a management plan for you, if necessary.