What on Earth is Havana Syndrome?

In July 2015, the US reestablished diplomatic relations with Cuba during a period known as the “Cuban Thaw”. The US Embassy in Havana reclaimed its official role once more, the early 1950s rectangular building with rows of neat windows welcoming back diplomats and intelligence officers to the Caribbean island. The following year, however, a growing number of people working in the Embassy reported odd symptoms, usually preceded by hearing a strange noise.

The symptoms included dizziness and balance issues, vision problems, memory holes and brain fog, headaches and intense feelings of pressure in the head and ears. Some people were found to have brain injuries similar to a concussion, but without the actual blow to the head. While this mystery illness was dubbed “Havana Syndrome” because that was where it was first reported, similar cases have been reported in other parts of the world, such as China, Moscow, Uzbekistan and even Australia.

The targets have largely been members of the United States intelligence or diplomatic communities and could number around 1500 people.

While it might seem obvious that the US might be being targeted specifically, what’s interesting about Havana Syndrome, the symptoms of which are more broadly referred to as Anomalous Health Incidents or AHIs, is that the explanations for it have never been definitively pinpointed, and while some people are sure it’s some type of targeted weapon being used against intelligence personnel, others are just as sure that it’s nothing but the latest case of mass hysteria and yet more people are convinced it’s something else again. Can we really blame the Russians for this one or is the truth somewhere in people’s own heads?

Potential Causes

First off, let’s get more of a handle on what Havana Syndrome actually is.

Regarding its effect on the human brain, an article from March 2024 on Medical News Today.com states:

Advanced brain magnetic resonance imaging (MRI) studies of individuals experiencing symptoms of Havana syndrome have shown abnormalities in the brain, including changes in:

• white matter integrity
• regional gray and white matter volumes
• cerebellar tissue microstructural integrity

Additionally, researchers found changes in functional connectivity in certain brain networks, including those related to vision and hearing.

According to a 2022 declassified document from the Director of National Intelligence, there were four “core characteristics” found among people thought to be suffering from Havana Syndrome, or Anomalous Health Incidents. These were:

the acute onset of audio-vestibular sensory phenomena, sometimes including sound or pressure in only one ear or on one side of the head;

other nearly simultaneous signs and symptoms such as vertigo, loss of balance, and ear pain;

a strong sense of locality or directionality and

the absence of known environmental or medical conditions that could have caused the reported signs and symptoms.

The Director of National Intelligence, who was Avril Haines in February 2022 when this report was written, and the Deputy Director of the CIA, who was David Cohen at the time, set up an expert panel of scientists, engineers and medical professionals to look into Havana Syndrome because of the link to US Government officials. It should be noted, though, that as per the report: “The panel did not examine questions related to attribution of AHIs to an actor, including the question of whether a foreign actor may be involved.”

We’ll come on to this later, but for now this report was trying to take a less sensationalist approach. It wasn’t ruling out foreign actors, though, it just wasn’t looking at who in particular it might be. The panel had a list of 5 potential causes for AHIs, which were “acoustic signals, chemical and biological agents, ionizing radiation, natural and environmental factors, and radiofrequency and other electromagnetic energy.”

Before we get to the big guns, let’s go through the slightly lesser known potential explanations from the report first.

Natural and Environmental Factors

To be honest, there’s not much to say here and while it’s stated in the report, there isn’t much follow-up information about so-called “natural and environmental factors” or what they could mean. The only detail given in the report is: “A subset of AHIs cannot be easily explained by known environmental or medical conditions and could be due to external stimuli.”

Ionizing Radiation

The DNI and CIA panel mentioned “ionizing radiation” as a possible cause for Havana Syndrome, however, this one was ruled out quite quickly. So quickly in fact, that it’s questionable why they even bothered putting it on the list in the first place. The report says: “Ionizing radiation, for example, produces known biological effects that are easily measured and inconsistent with the core characteristics.”

The idea behind this is that diplomats and intelligence officers were being targeted by some sort of x-ray, electromagnetic or radiation weapon. While this hypothesis of a targeted attack will come up again, we know that radiation was not involved as, at high levels, it causes burns on the skin and radiation sickness is a well-documented illness that doesn’t fit most of the characteristics of Havana Syndrome at all.

Chemical and Biological Agents

The anomalous health incidents were affecting a group of people in a specific place, namely, at first at least, the US Embassy and employee residences in Havana. Was there something that had been introduced into the area, whether nefariously or not, that was having negative impacts on some employees? When you think of the phrase “chemical or biological agents”, you are generally thinking of some sort of weaponised virus or compound that was intentionally released within or near the embassy in order to affect people working there.

Although “why” and “how” would be two pertinent questions in this case, they aren’t really that pertinent after all, because if there was a chemical or biological attack, it wasn’t a particularly successful one. Yes, some people became quite ill but no-one died and also not every person in the embassy was affected. Also, it would probably be easy to find traces of a chemical in the people tested for Havana syndrome, so the idea of a targeted chemical or biological attack has largely been ruled out.

But how about a more benign reason for the symptoms from an unintentional chemical source? Canadian diplomats were also affected by AHIs in Havana, and a Canadian report published in 2019 after the bulk of the cases had peaked, suggested that fumigation against mosquitoes carried out around diplomatic residences in the 2016 to 2018 time period could have caused Havana syndrome. There was an outbreak of the mosquito-borne Zika virus in the Caribbean including Cuba right at this time, meaning that fumigation was increased and, according to the report, both Canada and Cuba were fumigating around residences, meaning that there were a lot more chemical pesticides around than there normally would be, especially if it turned out that it was being doubled up in some areas. According to Reuters, researchers studying the brains of people affected by so-called Havana syndrome concluded that “cholinesterase, a key enzyme required for the proper functioning of the nervous system, was being blocked”.

The study then went on to say: “We report the clinical, imaging and biochemical evidence consistent with the hypothesis of over-exposure to cholinesterase inhibitors as the cause of brain injury.”

While this seems like a big reveal, they also made sure not to definitively say that Havana Syndrome was caused by spraying for mosquitos and that more study was needed. Also, because this was the main focus of the study, other potential causes couldn’t be ruled out.

There are, of course, questions to be asked here. What about your average Cuban? Why didn’t they get sick? Well, maybe some native Cubans also experienced Havana syndrome but didn’t have the same access to medical aid as the foreign diplomats.

As it’s a collection of symptoms, other people might have been treated for one specific issue and it only started encompassing the broader symptoms when a more influential subset of the population, i.e. North American intelligence officers and diplomats started experiencing them.

Also, it seems as though the diplomatic residences and other buildings might have been double-sprayed, thus exposing the people living there to a higher concentration of the enzyme inhibitor.

Acoustic Signals or a Sonic Weapon

One of the most enduring hypotheses about what is causing high-ranking US and Canadian government employees in various locations around the world to all experience the same set of symptoms, is that they are being targeted by some kind of sonic or acoustic weapon. A lot of the sufferers of the AHIs have stated that immediately prior to the onset of their issues, they heard a strange and/or loud noise, variously described as high-pitched, low and pulsing, and even like a marble spinning down into a large metal funnel.

This idea has gained traction and it’s easy to imagine a foreign spy aiming some sort of device at an office window or an individual and causing them to become confused and debilitated. Again though, the actual end game of this proposed tactic is not clear but let’s look at the plausibility of it.

While a “sonic” or “acoustic” weapon might not initially seem that scary, sound in general has been used as an interrogation and torture tool, probably forever. We’ve heard about people being deprived of sleep due to loud music being played, and this can happen anywhere from a prison cell to your inconsiderate neighbours. The CIA refers to blasting loud music at detainees in Guantanamo as “sound disorientation techniques” by the way. Sounds can be used to trick or confuse people into believing something is there when it isn’t, and there are certain sonic frequencies that can induce feelings of dread and anxiety in people too.

So could a targeted beam of sound be causing brain injuries to these people in various US embassies?

We know that there is already technology that weaponises sound in some forms. The US Military, for example, has used the Long Range Acoustic Device, or LRAD since the early 2000s. Colloquially known as a “sound cannon”, it can be used to either direct sound more precisely so messages can be relayed more effectively, or, as you might expect, it can also be used as a deterrent and even a weapon.

There is a built-in “deterrent tone” on the LRAD, which means that in instances such as for crowd control, the LRAD will blast out sounds in the 2,000 - 4,000 Hertz range, causing maximum discomfort to the human ear. An article on pitchfork.com describes it as “an invisible firehose”.

While it was developed for the military, some police forces have used a slightly downgraded version of the LRAD, although the New York Police Department was banned from using the so-called “alert feature” or deterrent tone in 2021, after several people sued the city after receiving injuries from it.

So could a targeted acoustic beam be behind Havana Syndrome? According to the Pitchfork article by Daphne Carr:

Unlike with other police weapons, the LRAD’s mechanism of injury, and the potential injuries themselves, are invisible. Still, the impact of its sound energy is an impact, just like a baton or rubber bullet, but its targets are the eardrums, hair cells, and organs of Corti inside your ears(…) Short-term exposure to loud noise like the LRAD’s deterrent tone may cause a sensation of stuffed or ringing ears, known as tinnitus, which can cease minutes after the exposure or last for days. Other sound injury symptoms include headaches, nausea, sweating, vertigo, and loss of balance.

Signs of more serious injury include vomiting and mucus or blood from the ears. Exposure to acute loud sounds can tear eardrums and destroy hair cells in the cochlea, which causes permanent hearing loss.

These symptoms do match up really well with the AHIs that have been reported. However, the type of sounds heard have not been consistent and also, an attack by something like a long-range acoustic device would affect anyone in the path at the same time. Also, the noise would presumably be constant and extremely loud, unless they’re shooting intermittent blasts, but as not everyone seems to hear it, it’s difficult to know if we’re on the right track here.

What does seem to be a prevailing theory is that some sort of targeted weapon is being aimed at these people. No overall consensus as to what it is has yet been reached, but this is a good time to take a quick history lesson.

Blasts from the Past

As it’s mainly American citizens that have experienced Havana Syndrome, if it is some sort of targeted attack on them in particular, it makes sense to look at who might want to disrupt the embassies and intelligence services. Yes, we’re looking at our old favourites, Russia and China. It might seem a bit lazy to just blame the Russians for playing dirty here, but since Putin came to power they have openly bragged about their development of “directed energy” weapons.

According to SputnikGlobe.com, in 2012, Russian Defense Minister Anatoly Serdyukov stated:

The development of weaponry based on new physics principles; direct-energy weapons, geophysical weapons, wave-energy weapons, genetic weapons, psychotronic weapons, etc., is part of the state arms procurement program for 2011-2020.

If they did procure any of these futuristic sounding things, it puts them right in the time window for the surge in Havana Syndrome cases. Anyway, we mentioned a quick history lesson, so let’s jump back in time a few decades to the 1950s and see what those Russians were up to then. The Cold War was starting to heat up, if you will, and you know what else heats things up? Microwaves.

Starting in the early 1950s, the Russians exposed Americans working at the US Embassy in Moscow to microwave radiation, beaming microwaves at the building, apparently as a way of countering listening devices that the US might be using against them. This became known as “Moscow Signal”.

Embassy workers were also exposed to high doses of ionizing radiation thanks to the atomic batteries that were powering radio transmitters that were being used to bug them. An article on the Foreign Policy Research Institute’s website states:

Tragically, three US ambassadors to Moscow, whose offices were regularly radiated, died of cancer at early ages—Chip Bohlen at sixty-nine, Llewellyn Thompson at sixty-seven, and, after suffering from nausea and bleeding in his eyes, Walter Stoessel at sixty-six.

Apparently, the use of the microwaves was kept under wraps, even though both sides knew about it. The Russians privately conceded they had been using microwaves but countered that the levels being directed at the embassy were not harmful. From the American side, it appears that while doctors and interagency staff were aware of the Moscow Signal, normal diplomatic staff were not necessarily informed that they were walking around being routinely exposed to potentially harmful microwaves. An article by James Schumaker for the American Foreign Service Association states:

One thing is certain: For years, our diplomats serving in Moscow were kept in the dark. This did not apply to the interagency community, however, which formed several groups to study the phenomenon and, apparently, to study our diplomats without their knowledge. (…)Meanwhile, blood studies were reportedly done on Embassy Moscow personnel, who were not told about the microwaves, but given the cover story that ‘viral studies’ were being conducted.

There are a few hypotheses as to what Moscow Signal was actually all about. We mentioned the one about the microwaves being used to counter US listening devices, but James Schumaker says: “However, as the Soviets themselves provided this explanation, it was naturally suspect.”

Other people think the microwaves might have been used to activate Russia’s own bugs inside the US Embassy.

In her 2017 book “Phenomena: The Secret History of the U.S. Government’s Investigations into Extrasensory Perception and Psychokinesis”, Annie Jacobsen writes about Moscow Signal and Dr. Robert Becker, who resigned from studying the oblivious embassy staff as he thought the whole thing was immoral. She writes:

Becker’s government work convinced him that a microwave signal such as the Moscow Signal ‘could affect the central nervous system, put people to sleep, interfere with decision-making capacity and induce chronic stress.’ He believed that the Soviets had been ‘using embassy employees as test subjects for low-level EMR [electromagnetic radiation] experiments.’

The real purpose of the Moscow Signal has never been definitively explained. The explanation for the secrecy, though, first from Embassy staff and then from the general public, was to maintain the fragile diplomatic relations between the two countries. It also transpired that the microwaves ended up being more harmful than the Russians believed, or at least said they believed at the time.

When they found out that they had knowingly been exposed to these microwaves, many US Embassy staff tried suing the government but it all ended up coming to nothing. A study released by the Johns Hopkins University School of Hygiene and Public Health in 1978 concluded that there was no proof of adverse health effects suffered by any embassy employees. A review of this report 40 years on, however, criticizes it to an extent that James Schumaker calls “devastating”.

While he doesn’t provide specifics, in his article he states:

The worst fear of embassy staffers was that the microwaves, whatever their purpose, might have some as-yet-unknown health effects. This seemed to be borne out over the years by the finding, in the early 1970s, that an unusual number of people were departing post with elevated white blood cell counts. It also came out that, anecdotally at least, there seemed to be a larger number of cancer cases, and especially leukemia, among former embassy staff than would appear to be normal.

Also,(…) a State Department doctor reported that several members of the embassy staff displayed symptoms that were nonspecific but had been reported frequently in patients chronically exposed to nonionizing radiation. Symptoms included severe headaches, inability to concentrate and fatigue.

Schumaker also provides his personal experience. He worked in the US Embassy in Moscow in 1977 when knowledge about the microwave bombardment was then out in the open, although activity had dropped off by then. After his first stint at the Embassy finished, he had a medical test in 1979 and was told that his white blood cell count was much higher than normal and to keep track of it. By 1985, a bone marrow test confirmed he had chronic lymphocytic leukemia, albeit at stage zero.

His condition worsened, then went into remission without any particular medical intervention. At the time he wrote the article, it had reappeared but not at a level that needed chemotherapy. As a healthy man with no family history of leukemia when he arrived in Moscow, he is leaning towards the idea that the microwaves he was exposed to there brought about the illness.

So, is the Moscow Signal a precursor to Havana Syndrome? We know that Russian agents were beaming harmful rays at Embassy buildings and staff, and that people were displaying symptoms in the 50s similar to what later appeared in 2016. Are they just doing it again, a few decades later?

Some Case Studies

While Havana Syndrome is so called because it seems to have originated in the Cuban capital, similar incidents have been reported by mainly US staff all over the world. This therefore rules out environmental factors or things such as the zika pesticide as these are not used worldwide. It also possibly rules out Russian involvement as cases have been reported in places like Australia, Switzerland and the UK.

One of the most compelling examples of someone experiencing AHIs is that of foreign trade officer Catherine Werner, a US diplomat who was stationed in Guangzhou, China until 2018 when she was medevaced out of the country due to serious health issues.

Werner’s problems began in 2017 when she started hearing strange sounds and feeling pressure in her head while in her apartment. As would be the case with most people, she justified it by assuming it was something like her air conditioning unit malfunctioning or a reaction to the smoggy pollution she was living in. As time went by, Werner started experiencing blurred vision, memory and balance issues, terrible headaches and nausea.

Her mother became concerned when she saw her on video calls and flew out to China to stay with her. At first, she started swapping out Werner’s usual food and water for imported supplies and changed the air filters in her apartment but Werner’s health didn’t improve and soon her mother, Laura Hughes, began to be affected too. As per an interview with NBC News in 2018, Hughes stated:

We heard a very high-pitched sound in Catherine’s bedroom. And we heard a very low, pulsing sound in the living room. Our heads would pulse. You would feel like you would want to regurgitate. You could become instantly paralyzed, instantaneously fatigued.

At this point, they also found signs that people might have broken into Werner’s apartment, and were fairly certain she was being spied on. Werner got two dogs but they also behaved oddly in the apartment, with Hughes saying they often found them shivering under beds and also vomiting blood. Hughes stayed in China for three months but found her health was too badly affected, so moved back to the States while her daughter was determined to remain.

Werner reported the suspected break-ins and her health issues to the Embassy who then gave her newly developed screening tests for Havana Syndrome. Her results matched up and she was flown back to the US where doctors found “vision, balance and hearing problems along with an organic brain injury”.

Living one floor below Werner was State Department security officer, Mark Lenzi. He and his wife also started suffering from headaches and memory loss and he heard the same loud rolling marble noise above his son’s crib on several different occasions. According to an interview with CBS, Lenzi “uses top secret equipment to analyze electronic threats to diplomatic missions.” He’s 100% sure that he and Werner were purposefully targeted with an energy weapon of “radio frequency energy, in the microwave range.”

In another example, a Canadian diplomat who has remained anonymous, was posted to Cuba for some short-term assignments, then was sent back in 2018. What he had not been told was that between his deployments, he already had signs of Havana Syndrome-esque brain damage but he’d been sent back anyway. The diplomat had been tested between his Cuban stints but the results had fallen through the cracks so he had no idea that he was walking back into a damaging situation. A 2021 piece from the Ottawa Citizen states:

The diplomat, whose mandate was security operations, was finally pulled from Cuba in January 2019 after his symptoms, including memory loss, cognitive difficulties and dizziness, grew much worse. By the time he called the Canadian government for medical help, he was unable to remember his access code.

‘I was a zombie, basically,’ he said. (…)He was sent back to Dalhousie University for urgent testing. In February, after the results came back, he received a letter confirming that he was case No. 15 in the Canadian government’s Havana syndrome file. Diplomats say they have been informed that there have since been dozens more who have been assessed for brain injuries.

There have also been a couple of high profile outliers in the date and location range but which do seem to point to the same conclusions as other examples - i.e. a targeted attack.

In 2007, well before Havana Syndrome became a thing, George W. Bush and team might have come under attack on the way to a G8 summit in Germany. His wife, Laura Bush provided some salient details in her 2010 memoir, Spoken From the Heart:

By the afternoon of [June 7] I could barely stand up. My head inexplicably throbbed; I was horribly dizzy and nauseated. I went to bed, pulled up the covers, and for several hours felt so awful that I might die right there in the hotel room … Nearly a dozen members of our delegation were stricken … For most of us, the primary symptoms were nausea or dizziness, but one of our military aides had difficulty walking and a White House staffer lost all hearing in one ear.

In 2019, a National Security Council staffer called Olivia Troye had a weird experience on her way towards the White House. In an appearance on CBS’s 60 Minutes, she recounts: “It was like this piercing feeling on the side of my head,(…) I remember it was on the right side of my head and I got like, vertigo. I was unsteady, (…), I felt nauseated, I was somewhat disoriented, (…) I remember thinking, … don’t fall down the stairs. You’ve gotta find your ground again and steady yourself.”

The incident appeared localised and the feelings dissipated the further from the entrance she got.

If we take Havana Syndrome as a real thing, it does seem as though something is targeting people. Sonic or acoustic weapons have been ruled out, but there are many proponents of the case for an electromagnetic or microwave-emitting device. Lewis Regenstein writing for the Foreign Policy Research Institute says:

In December 2020, the National Academies of Sciences, Engineering, and Medicine provided detailed evidence implicating weaponized microwaves as the cause of the Syndrome. The report, by a panel of nineteen experts in medicine and related fields, commissioned by the State Department, concluded that the ‘most plausible mechanism’ that caused the severe health effects during incidents beginning in 2016 was ‘directed, pulsed radiofrequency energy,’ a category that includes microwaves.

The only thing is that no evidence of any such device or anyone wielding one has ever been discovered and it remains a bit murky as to what conclusions have been come to here. Because of past form and the location of some attacks, Russia remains the prime suspect for potentially targeting American embassy workers. However, would they have been doing this in multiple other countries worldwide? Here’s where it gets tricky to unpick the evidence as there are many apparent examples of potential foreign agent involvement, but officially, the jury’s still out.

Julia Ioffe, a journalist and expert in Russian-US relations, wrote a piece for GQ in 2020 called “The Mystery of the Immaculate Concussion”. In the article, when referring to possible actual attacks she writes:

the most compelling evidence came from publicly available data such as mobile phone tracking information that allowed CIA investigators to deduce the whereabouts of Russian intelligence officers, and place them in close physical proximity to the CIA officers at the time they had been attacked when they were in Poland, Georgia, Australia, and Taiwan. In each case, individuals believed to be Russian Federal Security Service or military intelligence agents were within range of the CIA officers who had been hit in 2019. In two of the incidents, location data apparently showed Russian Federal Security Service agents in the same hotel at the same time their targets experienced the onset of symptoms.

Could these all have been coincidences? It seems unlikely that they all were. And no other nationalities appear to have been struck down with anything resembling what American officers were dealing with. Another damning report comes from the Foreign Policy Research Institute’s 2024 article titled: “Havana Syndrome: The History Behind the Mystery” by Lewis Regenstein. He writes:

Lt. Colonel Greg Edgreen, who headed the Defense Intelligence Agency unit investigating Havana Syndrome, states that intelligence reports from various agencies conclusively implicate the Russians as being the source of the incidents. One of these reports include a US citizen victim’s identification of a known Russian military intelligence officer, Albert Averyanov, the son of the deputy chief of Russian military intelligence, Andrey Averyanov, being outside her house in Tbilisi, Georgia at the very moment of an attack.

This seems pretty conclusive, but the official mouthpieces have still not definitively come out to say that this is what is behind the AHIs that Americans have been experiencing. Here’s a brief timeline:

In 2021, while some US intelligence officials were convinced of Russian involvement, a piece in the New York Times stated they had:

not found any hard evidence that points to a cause. There are no intelligence intercepts implicating an adversarial spy service. No one has detected microwaves, other readings of energy pulses or any other weapons that could be to blame.

Fast forward to 2023 and the CIA was almost definitely ruling out Russian involvement. Another New York Times article states:

the conclusions released(…)were broader, finding that none of the episodes the government investigated could be attributed to hostile foreign action.

The intelligence community assessment found that while seven different agencies had varying levels of confidence, most ‘concluded it is ‘very unlikely’ a foreign adversary is responsible’ for the reported ailments.

What did 2024 have to say on the matter? Another investigation here brought foul play back into the spotlight. The Foreign Policy Research Institute states:

On March 31, 2024, a joint, yearlong, extensively documented report by CBS’ ‘60 Minutes,’ The Insider, and Der Spiegel, was broadcast and released, which ‘uncovered evidence suggesting that unexplained anomalous health incidents, also known as Havana Syndrome, may have their origin in the use of directed energy weapons.’

How about 2025, any more updates there? Well, not anything substantive. The White House said the cause of Havana Syndrome was still unknown - leaving the door open for any interpretations you want.

Some intelligence agencies still thought foreign adversaries were “very unlikely” and others thought that some countries might have developed some sort of microwave weapon although it couldn’t be proven if they’d used it or not. There was apparently still no evidence or leaked intel from anywhere about anybody’s involvement and the New York Times says: “Some intelligence shows that foreign operatives were confused about Havana Syndrome allegations.”

If this leaves us, the general public, in a bit of a confused state, imagine what it’s doing to the people who’ve actually been suffering from Havana Syndrome over the last ten years. While up to 1500 people have reported a range of related symptoms, only a couple of hundred have had all the trademark symptoms of hearing the noise trigger, feeling pressure in their ears or heat in their heads and then the subsequent memory issues, headaches and balance problems. There have also been issues with people getting treatment or any kind of compensation for their impacted health because of one major sticking point with this whole Havana Syndrome debacle - which is that it could literally be all in peoples’ heads.

Mass Hysteria

It might seem a bit disrespectful to throw this term around after people have had real, serious and long-term health problems, however, it’s also really interesting so we’re going with it. At first you might think how on earth could this be a mass hysteria event, or, what is now referred to as a mass psychogenic or sociogenic illness or episode. People have suffered brain damage and reported similar symptoms in different areas all over the place, how can this not be a real thing? Well, the major headlines we might have heard concerning the “concussion but with no physical blow” don’t actually seem to bear out if you look a bit more deeply.

If you remember Mark Lenzi, he was the security officer based in China. The CBS interview he was in also spoke to his doctor, Dr. Teena Shetty about his symptoms. She said:

I was very surprised. He did not have any history of any trauma or blow to his head, but he reported a constellation of neurologic symptoms which are characteristic of mild traumatic brain injury, without any history of associated head trauma.

This can be read two ways. Either, he has a seemingly unexplained brain injury, OR, his descriptions of his symptoms pointed to a brain injury. She doesn’t actually say he has brain damage. I’m not doubting Lenzi or anyone else experienced physical symptoms, they’ve all been through many tests and suffered horribly, but the concussion thing does not appear to be an actual thing that happened to anyone.

In December 2023, Robert E Bartholomew and Robert W Baloh published an article in The International Journal of Social Psychiatry titled “‘Havana Syndrome’: A Post Mortem” which basically eviscerates the whole concept of it being a targeted attack. Regarding the damage to people’s brains, the authors explain that:

Several studies drew conclusions that were not warranted by the data. One found that patients ‘appeared to have sustained injury to widespread brain networks without an associated history of head trauma’ (…) But standard MRI scans of the brain were normal and based on the criteria for abnormal neuropsychological tests, just about anybody would be diagnosed with brain injury as the threshold for impairment was excessively high”.

They also take issue with the MRI techniques carried out and point out that 12 patients tested already had a history of concussions, whereas a control group had no such history, therefore making the differences between the groups more stark. Another study carried out on AHI patients showed damage to the otolith organs inside the ear, accounting for balance issues the sufferers had. Apparently though, according to Bartholomew and Baloh:

tests of otolith function are notoriously unreliable, and there was no appropriate control group.

Changes in the brain’s white matter was also challenged as only 3 out of 21 people tested had any white matter change and this could all be explained by aging, having migraines or suffering from depression, so everything was well within a normal or expected range.

A 2024 study by the National Institutes of Health also concluded that no brain injury had been found, or that by the time all their tests were done, no evidence of brain abnormality could be detected. After running participants through multiple types of testing, Dr. Leighton Chan said:

Our goal was to conduct thorough, objective and reproducible evaluations to see if we could identify structural brain or biological differences in people who reported AHIs. (…) While we did not identify significant differences in participants with AHIs, it’s important to acknowledge that these symptoms are very real, cause significant disruption in the lives of those affected and can be quite prolonged, disabling and difficult to treat.

In an interview with Spyscape, Dr Bartholomew stated:

After six years of investigating this case, and specializing in the study of mass psychogenic illness for the past 35, I am convinced that this is a case of mass psychogenic illness.

Let’s go a bit deeper. It might sound unlikely, but some people believe that the noise heard in Havana prior to the onset of peoples’ symptoms was not some kind of sonic or radiation weapon, but actually some local crickets. The Indies short-tailed cricket emits quite a high-pitched noise and, when comparing a recording of an alleged sonic attack with existing recordings of the crickets’ calling or mating song, they are extremely similar. If these crickets were feeling especially randy, or their calls were amplified or distorted by the building’s acoustics, it’s not impossible that this is the noise people were hearing, especially if they were not familiar with this particular insect.

It could be that the high-pitched noises were incidental to, rather than a precursor to the health issues. The noise was not the same in other parts of the world, either, maybe giving more credence to the crickets idea. In China, it was described as a lower, rumbling sound, meaning that if the noises and health symptoms are related, it was from a different source or again, just a coincidental noise that was later linked to the AHIs. Many other people with AHIs did not hear any noise at all.

That’s another issue with Havana Syndrome - the symptoms reported are many and varied, with so much variation, in fact, that only a few people have been deemed to be suffering from it despite many hundreds of potential patients. As per the Bartholomew - Baloh article again, they contend that the 2023 investigations into Havana Syndrome concluded that:

Havana Syndrome” was a socially constructed catch-all category for an array of pre-existing health conditions, responses to environmental factors, and stress reactions that were lumped under a single label. In reviewing the history of this condition, many factors led to its erroneous categorization as a novel clinical entity.

So does Havana Syndrome come under the banner of a psychogenic illness? Were people basically manifesting real symptoms but under imaginary circumstances? It is possible and happens quite a lot. The Embassy in Cuba had only just reopened.

There may well have been some environmental factor that affected foreign visitors more than the local population. Tag on an unfamiliar noise and then rumours of targeted attacks, and people start becoming stressed and overly paranoid, perhaps leading to deteriorating health which then seems to spread throughout a specific cohort.

Some people argue strongly against this, but although they state things that are factually correct, these statements don’t have any bearing on who might suffer from a psychogenic illness. We hear things like the people who work in the Embassy or for intelligence services are mentally strong, used to high pressure situations, very resilient, etc. This kind of talk portrays people suffering from mental or psychological illness as weak-minded and who could become hysterical and imagine things.

This is why the medical world has moved on from the term “mass hysteria” as it paints the sufferers in a very negative light, making them seem prone to silliness, having weak mental capacities or even just making everything up. This is obviously not true as anyone can suffer from a psychiatric, neurologic or psychogenic illness.

According to Bartholomew and Bahlo’s takedown article, mass psychogenic illness was dismissed by one study of Havana Syndrome patients. They write:

The lead author later said that the team had dismissed a psychological cause as there was no evidence of collusion among patients. He said, for mass psychogenic illness to occur you must have all the patients ‘in collusion together to make sure all their symptoms match’”.

This is not true, as in general, with incidents of mass psychogenic illness, people are not meeting up to discuss what symptoms they’re going to have and how they’re going to display them, that’s not how the condition works. While we still don’t know that much about psychogenic illnesses or functional neurological disorders, we do know that even if the cause or inciting incident isn’t a physical thing, the symptoms that people suffer are real.

While some Havana Syndrome cases can definitely be explained by existing conditions plus stress, etc., surely not all cases can be explained this way though, right? Well, even with the few seemingly unexplained cases, there might not be cause to blame foreign enemies. Dr Bartholomew also says in his Spyscape interview:

The confusion with the case is the result of politics mixing with science. While the CIA is continuing to investigate a small number of cases that are classified as ‘unexplained,’ this does not mean that there is some nefarious plot against American diplomats and intelligence officers. A recent US government investigation on UFOs found that many cases were unexplained. But that does not mean that they were ETs.

Many of these cases lack sufficient information on which to base an assessment. The same is true with Havana Syndrome.

In an article for TheConversation.com, Professor Robert Baloh states:

The story of Havana syndrome looks to me like a textbook case of mass psychogenic illness. It started from a single undercover agent in Cuba – a person in what I imagine is a very stressful situation. This person had real symptoms, but blamed them on something mysterious – the strange sound he heard. He then told his colleagues at the embassy, and the idea spread. With the help of the media and medical community, the idea solidified and spread around the world. It checks all the boxes.

One point against a psychogenic event, though, is that apparently, in the Chinese examples, neither Catherine Werner nor Mark Lenzi were aware of their colleagues in Cuba having been hit by this mystery ailment. Does this mean that these are, in fact, totally unrelated after all? It was the larger organization that connected the dots for the two, not them saying it was Havana Syndrome. Maybe they connected dots that weren’t actually there and these two people just happened to be affected by something else within the same time period.

Or does it point to the fact that the attacks are real and really being carried out by malicious actors? Unfortunately for us, there’s no available evidence to really confirm things either way. Psychogenic illnesses are understood to be real symptoms without a physical cause, however, it’s still kind of a nebulous label that isn’t particularly helpful to the people suffering from it, especially if they themselves don’t believe it’s a psychologic or neurologic issue.

Treatment

So where does this leave the people who have been diagnosed with Havana Syndrome or have otherwise suffered strange and debilitating symptoms? Well, the whole thing is still basically a mystery and because of the variance of symptoms, there is no treatment for Havana Syndrome per se, so the individual symptoms have to be treated instead.

Unfortunately, a lot of potential US government employee sufferers and their families have found it difficult to access the Military Health System to get clarification about what they can do or what can be done for them. Some people reported that they were not believed or that their symptoms weren’t taken seriously. The CIA did take a more serious approach but, to begin with, the US Government’s response to the AHIs was not a united one.

Eventually, in 2021, Congress passed a bill called the “Helping American Victims Afflicted by Neurological Attacks Act”. The acronym is the HAVANA Act. According to Congress.gov:

This bill specifically authorizes the Central Intelligence Agency, the Department of State, and other agencies to provide payments to agency personnel who incur brain injuries from hostilities while on assignment.

This helped to legitimize the condition and clear the pathway for people to get support.

In addition, the US Government Accountability Office made 6 recommendations to the Department of Defense in 2024, generally tasking them with improving communication and organizational admin regarding patients with Anomalous Health Incidents. It seems that these recommendations were all implemented in 2025.

It does seem that the US Government is taking the worst cases of Havana Syndrome seriously, or at least they want the best possible healthcare outcomes for those affected. The panel from the Director of National Intelligence and the CIA ends by saying: “The panel was moved by the experiences of individuals affected by AHIs. They deserve the best possible care, as well as appreciation for their sacrifices.”

Some people are still living with the effects of their AHI many years after it first started but we’re still none the wiser about the cause. Could these people have been targeted by some kind of energy, acoustic or radiation weapon? Maybe, but no evidence of a weapon has ever been found, nor any intelligence communications leaked or discovered. Also, if US government employees were or are being targeted, it just seems a bit of a weird way of going about things.

“Why” is the main question, as causing a few people to become ill isn’t an effective way of doing anything.

Some kind of stress reaction or psychogenic illness might seem plausible, but then you’ve got other random but very similar events such as George W Bush and his entourage coming down with symptoms years before the 2016 Havana Syndrome episodes, and employees in China also suffering the same symptoms without knowing of the outbreak in Cuba. It might seem a little too easy to blame it all on the mind, then the US doesn’t have to publicly accuse other countries of causing their citizens harm. Maybe diplomacy is more important than the health of a couple of hundred workers.

Because this is set in the intelligence community, an extra layer of shadow hangs over the whole Havana Syndrome story, meaning that even if the truth is already known, we might not ever get to hear it.

Latest Update

Towards the end of the Biden administration at the end of 2024, Homeland Security Investigations, a division of the Department of Homeland Security, paid “eight figures” i.e. tens of millions of dollars for a device they believe could potentially be linked to Havana Syndrome, after obtaining it through “an undercover operation.”

According to an article from CNN, the device “produces pulsed radio waves” and it’s been tested for over a year. Is this finally the smoking gun everyone’s been waiting for? Well, time will tell, but nothing’s been conclusively proven yet, or at least, the public hasn’t heard about it. According to a source who spoke to CNN, there are Russian components to the device but it’s “not entirely Russian in origin.”

Apparently it’s also portable, being small enough to fit into a backpack. Questions that have arisen from the uncovering of this news are; where did HSI get this device from and how did they find out about it? There are also concerns that the technology might have already spread to other actors or regimes.

Unsurprisingly, no-one from the Department of Defense, the Department of Homeland Security or the CIA has commented publicly on the matter yet.

The CNN article ends with a quote from Marc Polymeropoulos, a CIA officer who believes he was targeted in Moscow in 2017. He says:

If the [US government] has indeed uncovered such devices, then the CIA owes all the victims a f**king major and public apology for how we have been treated as pariahs.

CBS News.com also published a quote from Polymeropoulos where he said:

The CIA always claimed that none of this technology even existed, that a device didn’t exist, and they based their [assessments] on this, (…) so their entire analytic assumptions are now blown up.

The best conclusion we can come up with for the moment is: watch this space.

Frequently Asked Questions

What is Havana Syndrome and when was it first reported?

Havana Syndrome is a collection of mysterious symptoms first reported in 2016 among US Embassy staff in Havana, Cuba, following the reestablishment of diplomatic relations in July 2015. Symptoms included dizziness, balance issues, vision problems, memory holes, brain fog, headaches, and intense pressure in the head and ears, sometimes preceded by hearing a strange noise. Some people were found to have brain injuries similar to a concussion without receiving an actual blow to the head.

How many people have been affected by Havana Syndrome and where else have cases been reported?

Approximately 1,500 people have reported symptoms, with targets largely being members of the United States intelligence or diplomatic communities. While first reported in Havana, similar cases have been reported in other parts of the world including China, Moscow, Uzbekistan, and Australia.

What brain abnormalities have been found in MRI studies of Havana Syndrome patients?

Advanced brain MRI studies from March 2024 showed abnormalities including changes in white matter integrity, regional gray and white matter volumes, cerebellar tissue microstructural integrity, and functional connectivity changes in certain brain networks including those related to vision and hearing.

What were the four ‘core characteristics’ of Anomalous Health Incidents identified in the 2022 declassified DNI report?

The four core characteristics were: (1) acute onset of audio-vestibular sensory phenomena, sometimes including sound or pressure in only one ear or on one side of the head; (2) other nearly simultaneous signs and symptoms such as vertigo, loss of balance, and ear pain; (3) a strong sense of locality or directionality; and (4) the absence of known environmental or medical conditions that could have caused the reported signs and symptoms.

What five potential causes for AHIs did the DNI/CIA expert panel identify?

The panel identified five potential causes: acoustic signals, chemical and biological agents, ionizing radiation, natural and environmental factors, and radiofrequency and other electromagnetic energy. However, the panel explicitly did not examine questions related to attribution of AHIs to a foreign actor.

What is the ‘Moscow Signal’ and how does it relate to Havana Syndrome?

The Moscow Signal was a Cold War incident starting in the early 1950s where Russians exposed Americans at the US Embassy in Moscow to microwave radiation, apparently to counter US listening devices. Embassy workers displayed symptoms similar to later Havana Syndrome cases, including headaches, inability to concentrate, and fatigue. Some believe this could be a precursor to Havana Syndrome, suggesting Russia may be using similar tactics again.

What did the 2020 National Academies of Sciences report conclude about the cause of Havana Syndrome?

The December 2020 report by a panel of nineteen experts concluded that the ‘most plausible mechanism’ causing the severe health effects was ‘directed, pulsed radiofrequency energy,’ a category that includes microwaves.

What evidence has been presented linking Russia to Havana Syndrome incidents?

Journalist Julia Ioffe reported that mobile phone tracking data placed Russian intelligence officers in close physical proximity to CIA officers at the time of attacks in Poland, Georgia, Australia, and Taiwan. In two incidents, location data showed Russian Federal Security Service agents in the same hotel as targets experiencing symptoms. Lt. Colonel Greg Edgreen stated intelligence reports conclusively implicate Russians, including one case where a victim identified Russian military intelligence officer Albert Averyanov outside her house in Tbilisi, Georgia at the moment of an attack.

What is the mass psychogenic illness theory of Havana Syndrome?

Researchers Robert E Bartholomew and Robert W Baloh argue Havana Syndrome is a case of mass psychogenic illness (now called mass sociogenic illness). They contend that standard MRI scans were normal, neuropsychological test thresholds were excessively high, and studies had methodological flaws like inappropriate control groups. They argue ‘Havana Syndrome’ became a socially constructed catch-all category for pre-existing health conditions, environmental factors, and stress reactions. The 2024 NIH study found no significant brain or biological differences in AHI participants.

What is the HAVANA Act and what does it do?

The Helping American Victims Afflicted by Neurological Attacks Act (HAVANA Act) was passed by Congress in 2021. It specifically authorizes the CIA, Department of State, and other agencies to provide payments to agency personnel who incur brain injuries from hostilities while on assignment, helping legitimize the condition and clear pathways for people to get support.

Sources

• Original Decoding the Unknown video: What on Earth is Havana Syndrome?
• Hero image source by Phillip Pessar / openverse, by.