Weird Medical Stories: What Is Havana Syndrome?

F. Perry Wilson, MD, MSCE


July 23, 2019

This transcript has been edited for clarity.

Welcome to Impact Factor, your weekly dose of commentary on a breaking medical study. I'm Dr F. Perry Wilson.

This week, we dive headlong into the mysterious world of spies, energy weapons, and potential mass hysteria, as this study[1]—appearing in JAMA—reignites one of the weirdest medical stories from the past 5 years.

It's colloquially known as "Havana syndrome." In late 2016, American diplomats in Cuba started to experience a strange set of symptoms. It started abruptly with pressure in the ear, and was sometimes associated with a high-pitched noise that sounds something like this.

It was disorienting; in some cases, painful. Sequelae included headaches, nausea, visual problems, gait instability, and hearing loss. Some individuals are still symptomatic.

Was this some new microwave weapon? A directed energy beam? A sonic device?

Subsequent analysis revealed that the sound I played you earlier was actually a species of cricket native to Cuba. This led some to suggest that this was not an attack at all but rather mass psychogenic illness—a product of persistent Cold War thinking in an incredibly stressful environment.

Whatever the cause, the United States dramatically reduced its diplomatic core in Havana in September 2017. In October of that year, President Trump said the following: "I do believe Cuba's responsible. I do believe that."

In [March] 2018, JAMA published a study[2] looking at MRI data from 21 individuals who had developed the syndrome. The results were fairly inconclusive, with some changes seen in brain networks but no major structural abnormalities.

The new study in JAMA gives us more detailed brain imaging than we ever had before, and ups the ante by comparing affected individuals with matched controls.

Here are the details.

The researchers identified 40 patients with Havana syndrome and matched them to 48 healthy controls. All participants underwent traditional structural MRI, diffusion imaging, and functional MRI (fMRI). Statistically significant differences between patients and controls were seen across a variety of domains.

Here's a smattering:


Patients had less white matter in their brain than controls, but no difference in gray matter. They had greater white matter in projection fibers, but less in association fibers. fMRI revealed deficiencies in the auditory and visual subnetworks, but not in the executive function subnetwork. In the cerebellum—specifically examined because of the constellation of symptoms, which often included dizziness—there was lower mean diffusivity in the cerebellar vermis and higher fractional anisotropy.

I'm not a neurologist, so I asked lead author Dr Ragini Verma what she made of these findings.


So what do we make of this? Well, one take is that we are seeing the clear neurologic sequela of...something—maybe a weapon, maybe an as-of-yet unidentified virus.

But that's not the only interpretation. We have no baseline scans on these diplomats, so we can't compare their brain findings before and after their stint in Cuba. The authors compared them with matched controls, but good matches are hard to find. They tried to get individuals with college degrees and jobs that require multitasking, but the tasks of diplomacy in a nation such as Cuba may put unique stresses on these individuals, independent of any secret weapons. If I were picking a control group, I'd scan the unaffected diplomats in Cuba and see how their brains look.

I'll be honest—I'm not really sure what's going on here, but it is clear that these diplomats are suffering, and I'm glad to see researchers trying to determine exactly why. That being said, I have a feeling this story may get weirder before the truth wins out.


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