Medical Examiner

If a Weapon Didn’t Cause Havana Syndrome, What Did?

A blurry shot from behind of a man with his right hand to his head
Photo illustration by Slate. Photo by Pornpak Khunatorn/iStock/Getty Images Plus.

In January, a CIA task force investigating “Havana syndrome,” the unexplained malady involving symptoms such as intense brain fog and nausea that has struck U.S. government personnel around the globe, concluded in an interim report that this was probably not the result of a sonic weapon, a microwave weapon, or secret, high-tech attacks by a hostile foreign government, as had been widely speculated.

The announcement was met with dismay in some corners. A support group for Havana syndrome sufferers issued a statement that the findings were a “repudiation” and that they “cannot and must not be the final word on the matter.” Republicans and Democrats alike also bristled in surprise: “Everything we’ve been told up to now is different,” Senate Foreign Relations Committee Chair Bob Menendez told reporters.

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But for others of us who have been closely following this saga, the report was not shocking. Rather, it was a relief. As I wrote here four years ago, there were “no details, no motive, and no plausible explanation for what kind of weapon this might be.” By finally acknowledging so much, the CIA might actually be helping Havana syndrome patients—some of whom are still struggling with its effects—get closer to an accurate diagnosis and effective treatment.

What might that diagnosis be? Unfortunately, we can’t say for sure. The CIA report was not released to the public—intelligence officials only described its contents to journalists—and news reports were hazy on certain key details. The government is still exploring about two dozen unresolved cases; the rest, according to NPR, “appear related to previously undiagnosed medical conditions or stress.”

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However, many experts believe that Havana syndrome likely belongs to a category of illnesses known as “functional neurological disorders,” or FNDs. Broadly speaking, these are illnesses caused by neural pathways being inhibited or created in such a way as to cause a person pain, loss of motor control, sensory problems, language issues, fatigue, and other symptoms. As Mark Hallett, NIH distinguished investigator and president of the Functional Neurological Disorder Society, recently explained in presentation on the society’s website, it is “a neurological disorder … caused by a brain network dysfunction.” You can get much deeper in the weeds, but that’s the nut of it: Certain things the brain does go haywire. Given that our brain has 100 trillion neural connections, this should not be surprising.

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On rare occasions, the symptoms of functional disorders become contagious, passed from person to person via “social contagion” or “social learning.” In this case they constitute a “mass psychogenic illness”—or, more colloquially, mass hysterias—that can move across the world quickly, usually through social networks. A recent wave of tics spreading (ironically) through TikTok is one example. Havana syndrome is mostly likely another.

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Functional disorders and mass psychogenic illnesses are controversial because of the common misconception that patients suffering from them are merely imagining their symptoms. Nothing could be further from the truth, and Havana syndrome well fits the profile of a functional disorder. The controversy over it started in late 2016, when a number of diplomats in Cuba reported hearing a strange sound, then began to have adverse symptoms including fatigue, memory problems, ear pain, hearing loss, brain fog, nausea, dizziness, and headaches. A few managed to record the sound, which led to speculation that a foreign power had invented a “sonic weapon” that it was using against them. (A later analysis determined the sounds were the loud song of the Indies short-tailed cricket.)

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Stories of the attacks spread and so did the number of people suffering similar symptoms, which would grow to affect about 1,000 people around the world. Brain scans of the some of the early sufferers were said to show changes in “white matter tracks,” which were interpreted as brain damage. Armchair neurologists like Sen. Marco Rubio seized on this. As recently as October, he accused anyone who suggested these were not from a weapon of “quackery.”

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“I’d invite them to explain that to the now-dozens of people who have suffered documented brain injuries that in many cases have made them incapable of ever working again,” he said.

But these brain injuries were not as well documented as Rubio and others have suggested. Since that study’s publication, critics have pointed out that the white matter tracks observed are characteristic of brain changes (including FND), not necessarily brain damage. They also noted that the symptoms reported by Havana syndrome sufferers are common across the population. Most of us have had, or will have them, at some point in our lives. Usually, they resolve on their own. But in the right circumstances they can persist, worsen, and become debilitating. These are the conditions FND specialists see in their office every day.

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One reason patients often have trouble coming to terms with an FND diagnosis is that there isn’t a simple cause or a clear-cut mechanical reason why their brain’s network began to malfunction. Rather than a single starting point, FNDs tend to result from a constellation of risk factors. These include traumatic life events, anxiety and depression, being in transitional phases of life, illnesses, and accidents. Women seem to be more at risk, as do people in their 20s who are transitioning from high school to college or from college to work. But there is almost never the sort of clear causal chain people tend to expect in our mechanically minded medical culture—no smoking gun or secret microwave weapon.

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“Human nature is to look for cause and effect,” says Robert Baloh, professor of neurology and head and neck surgery at UCLA’s David Geffen School of Medicine and co-author of Havana Syndrome, which argues that what took place in Cuba was a mass psychogenic illness. “I see this daily when I see patients. They’re all sure something they ate or something they did caused their problem and their symptoms.”

This has long been a problem with neuropsychiatric conditions like chronic fatigue syndrome and fibromyalgia, which are considered functional disorders by most FND specialists. Despite the fact that the best hope for treatment may well be found in treating them as such, too much time, energy, and resources have been spent looking for a clear causal chain in order to prove that these disorders are “real.”

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The fact that these disorders sit at the convergence of multiple roads, rather than the end of a single pathway, doesn’t make them any less serious, however. It doesn’t mean the symptoms are all in a patient’s head, nor does it mean they’re simple to treat. In fact, the longer such dysfunctional patterns are allowed to run, the more deeply ingrained they get, with a higher risk of becoming permanent.

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“It isn’t real versus not real,” says Baloh. “It’s different mechanisms. They’re all real. People can be devastated with symptoms.”

Consider the case of Miranda Licence, who experienced one of the more extreme cases of FND I have encountered in my reporting. One day in 2015, she went for a run down the road in the town of Toowoomba, Australia, where she lived and taught elementary school. She came home with a headache and laid down for a nap. When she woke up, she could barely move. She could feel her limbs, so she knew she wasn’t paralyzed. But her limbs felt oddly heavy. “It was really strange,” Licence said when I asked her about it. “I just didn’t feel like I had the ability to remember how to move.” She was transported to a local hospital, and after a few days lying in bed, her doctor told her she had a “functional neurological disorder.” Licence had never heard of such a thing.

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“The frustrating part,” she said, “was that they couldn’t really explain what that meant in terms of recovery.”

Licence lay in the hospital for a month before she was transferred to a regional hospital in Brisbane. While her condition now had a name, no one was quite sure how to treat it. So she and her father did their own research, then handed it to her new physiotherapist, Rajesh Singh, who read through the literature and came back with an idea.

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License couldn’t walk, and had trouble moving at all. But running was a slightly different motor pattern than walking. So he propped her on a treadmill, cranked up the speed, and, sure enough, Licence took off. Even though she couldn’t walk, she could run. There was nothing wrong with her legs. There was no “structural” damage to her brain. It was just that when she tried to move her legs, she couldn’t. Her intention was disrupted. She had a problem in the function of her neural pathways.

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“My explanation to patients,” says Kathrin LaFaver, a neurologist with the Saratoga Hospital Medical Group, “is that what we have is basically a signal problem, where the brain doesn’t send the correct signals to the body for movement initiation, so you lose control over movements that are generally under your control.”

At the hospital, Licence ran. And as she did, her therapist slowed the treadmill down until she was walking. This helped reestablish the motor pathways between her brain and legs. She ran both forward and backward, slowing down until she could walk. It took about three weeks, but then she was released back to her life, both her walking and her running.

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“I played hockey the next weekend after I got out of the hospital. Since then, I’ve been fairly normal,” License says. She has had a few relapses, usually after getting a cold. But these lasted between one and three days, and she was able to use what she’d learned to regain her motor control. “I think I’m one of the lucky ones, as far as I can tell.”

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License’s story should put to rest any notion the victims of FNDs are merely imagining things; the symptoms of these disorders can literally be crippling. But her example also illustrates something important about treatment. Prospects for recovery from FND vary but are generally better if it’s diagnosed early, as in Licence’s case. Having an understanding of the nature of the condition helps too, as does belief that FNDs are real.

“If you say to someone, ‘The reason you can’t move your leg is basically a software problem in your brain, rather than a hardware problem,’ it enables you to say to the patient, ‘Look, we can try and retrain your brain with physical therapy or retrain your brain with psychological therapy to try and get this software changed,’ ” says Jon Stone, a consultant neurologist for Britain’s National Health Service and honorary professor of neurology in Edinburgh. At the same time, patients also need to address the risk factors like anxiety, depression, and life stress. “It’s really combination of the physical and psychologic factors that need to be addressed for people to get better,” LaFaver says, “FND lives on that borderland between neurology and psychiatry.”

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But FND skeptics don’t want to talk about Havana syndrome at the psychological level or even the neurological level. Instead, they want to talk about it at the political and military level. And while victims may feel like politicians hunting for phantom ray guns are advocating for their interests, the reality is that this may be setting back their chances for recovery by preventing them from confronting the reality of their condition. If we want to make progress against Havana syndrome and similar conditions, it’s time to drop the sci-fi conjecture about sonic weapons and take aim at the real target.

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