• In the fall and winter of 2001–2002, school children across the United States began to break out in a strange rash (Talbot 2002). Groups of children in Pennsylvania, Oregon, and Virginia, overwhelmingly girls, turned up with itchy red blotches at school that disappeared when they went home. All of this happened in the post-9/11 environment of anthrax scares and worries about terrorist attacks. No toxins were ever found, but eventually the scratching stopped, and the rashes went away.
• On Christmas Eve in 1021 CE, eighteen people gathered outside a church in the German town of Kölbigk and began to dance wildly, seemingly involuntarily (Waller 2009). They organized in a ring and clapped and chanted, disrupting the mass that was going on inside the church. According to legend, the priest was so enraged that he cursed the dancers to dance for an entire year, which they reportedly did, falling into a deep sleep the following Christmas Day. Some of them never woke up. Soon other dancing outbreaks cropped up throughout Europe, one of which inspired a new dance. A late fifteenth-century outbreak of dancing in Taranto, Italy, was blamed on bites from a local species of spider, and the Tarantella was born (Esterianna and Richard the Poor of Ely n.d.; Waller 2009). 
• In 2017, news reports emerged of health problems among workers at the U.S. Embassy in Cuba, including hearing loss and mild traumatic brain injury (Associated Press 2017). Many believed these health problems were caused by a previously unknown sonic weapon employed by the Cubans. President Donald Trump expressed his view that the Cubans were responsible, and the United States responded by ejecting fifteen Cuban diplomats and withdrawing most of its diplomatic staff from Havana (Oppman 2022). In January 2018, the U.S. Senate held a hearing titled “Attacks on U.S. Diplomats in Cuba: Response and Oversight” (United States Senate Committee on Foreign Relations 2018), and in October 2021 President Biden signed the “Havana Act of 2021,” otherwise known as the “Helping American Victims Afflicted by Neurological Attacks Act of 2021” (United States Congress 2021).

The Unacceptable Diagnosis

The understandable reaction to the medical problems in the three cases above was to search for an environmental cause—a toxin, poisonous spider bites, or a sonic weapon—that would provide a plausible explanation and, perhaps, someone to blame. In the case of dancing mania, the theology of the European Middle Ages offered a ready solution: possession by demons. But in each of these cases, there is strong evidence that the real cause was psychological rather than medical or supernatural, making the puzzle of responsibility more difficult to solve. For several reasons, this message is not easily absorbed when you are suffering from real physical symptoms. “It’s all in your head” is neither a helpful nor an entirely accurate diagnosis.

It used to be called mass hysteria, but because hysteria originally referred to a collection of classical ailments thought to afflict only women, the term has been quite appropriately placed on the ash heap of outmoded psychiatric terms. Today the more common term is mass psychogenic illness, which is sometimes contrasted with somatogenic illnesses that have physiological origins (Baloh and Bartholomew 2020). But the name change has not made the diagnosis any more palatable, which is a serious problem.

Mind and Body

Under many circumstances we have no difficulty accepting psychological causes for bodily things. This is particularly true when the effect is positive. Meditation, music, and regular exercise can all reduce stress, lower blood pressure, and improve mood (Cleveland Clinic n.d.). In addition, placebos can produce powerful effects. It is estimated that between 65 and 80 percent of the positive effect of serotonin reuptake inhibitors (e.g., Prozac) on depression can be duplicated by administering a placebo, an inert sugar pill that the patient believes contains active ingredients (Kirsch 2000). Expectations are powerful things.

Even when the health effects are negative, under some circumstances, the “all in your head” verdict is easier to accept. For example, research suggests that much of the temporary adverse effects people—me included—reported after receiving the COVID-19 vaccines was a nocebo effect, a negative placebo-like effect created by the expectation of a bad reaction. A January 2022 meta-analysis found that an average of 35 percent of people in the placebo wings of COVID-19 vaccine trials experienced adverse reactions after the first dose (of a placebo!), with headache and fatigue being the most common symptoms¹ (Haas et al. 2022). In comparison, on average 46 percent of people in the vaccine wings of these studies reported adverse effects. The percentage of people reporting adverse reactions in the placebo groups was significantly lower for the second injection, and fewer people reported bad reactions in the placebo groups than in the vaccine groups. But the authors estimated that 75 percent of the adverse reactions to COVID-19 vaccines could be accounted for by the nocebo effect.

That’s a lot of real illness—not to mention missed days of work and lost income—caused by psychological phenomena, and yet as far as I know there has been no widespread outrage or calls for congressional hearings. There are at least two reasons for the difference between the COVID-19 nocebo effects and Havana Syndrome described above. First, the adverse reactions to the coronavirus vaccines are short-term. There have been very few reports of sustained adverse reactions subsequent to vaccination. In contrast, the people suffering from Havana Syndrome report illnesses that have persisted for years in some cases. Second, the people who got vaccinated chose to do so. Most people who received the COVID-19 vaccines went in knowing that there might be a brief adverse reaction, and they factored that into the decision to get vaccinated. Several of my friends scheduled their vaccination appointments so that they could afford to miss work or school for a day or two after. In contrast, the embassy workers in Havana were just minding their own business and did not ask to experience the symptoms they came down with. 

Interestingly, mass psychogenic illnesses following vaccinations were common long before COVID-19. One clue that these reports were psychological in origin came from the observation that military recruits sometimes faint while standing in line for vaccinations at induction. Meanwhile, infants and toddlers do not show similar pre-and post-injection reactions. Babies are scared and typically scream and cry when poked with the needle, but even when administered with groups of other infants, they generally do not faint. Loss of consciousness by a baby soon after vaccination—were it to occur—is considered a serious medical event (Clemments 2003). 

What Exactly Is Mass Psychogenic Illness? 

There appears to be no widely agreed-upon definition of mass psychogenic illness, but in 2010, a group of British researchers offered the following five-point definition (Page et al. 2010):

1. Presence of somatic (bodily) symptoms.
2. Pre-existing social connection between two or more of the affected people.
3. An epidemic spread of the symptoms.
4. Attribution of symptoms by patients (or parents/caregivers) to threatening external agent of a physical or spiritual nature. 
5. Symptoms and signs that are not compatible with the environmental explanation offered by victims or with other plausible environmental toxins introduced at the time of onset.

Criteria 1 through 4 are often present, but they do not rule out an environmental cause. Often it is criterion 5 that tips the balance in favor of mass psychogenic illness. For example, the 9/11 rash went away when the students went home—which seemed to implicate the school environment—but the affected students were overwhelmingly girls. Investigators found no plausible explanation for why boys would not be affected by a toxin. 

Similarly, in the case of the Havana Syndrome, the “attacks” were presumed first to be caused by acoustic and later by microwave energy (Swanson and Wong 2020), but experts in acoustics and microwave technology suggested it was extremely unlikely that a weapon could produce the kind of brain damage claimed in these cases (Baloh and Bartholomew 2020). Sound has been successfully used as a weapon, but typically it comes in the form of really loud music.

Over a year ago, Robert W. Baloh, a professor of neurology at UCLA, and Robert E. Bartholomew, a medical sociologist and fellow of the Committee for Skeptical Inquiry, wrote Havana Syndrome: Mass Psychogenic Illness and the Real Story behind the Embassy Mystery and Hysteria. Their very thorough analysis reads like a spy thriller and covers both the long history of mass psychogenic illnesses and the specific case of Havana Syndrome. They point out the unlikeliness of the foreign attack hypothesis and suggest that less sinister explanations fit better. For example, early in the Cuban episode, the FBI had an expert on Latin American insects listen to a recording of sounds thought to be associated with the attacks. The expert said the sounds were probably crickets, cicadas, or katydids. The sonic attack theory eventually faded in favor of microwaves (Baloh and Bartholomew 2020), but there is no credible evidence of a microwave weapon either. 

As might be expected, Baloh and Bartholomew got lots of pushback on their conclusion that Havana Syndrome was a new example of mass psychogenic illness, but recently their view has begun to receive greater acceptance. In January 2022, the CIA reported that it was “unlikely that a foreign actor, including Russia, is conducting a sustained, worldwide campaign harming U.S. personnel with a weapon or mechanism” (Harris and Ryan 2022). The wording of this statement is quite careful, and it avoids identifying Havana Syndrome as a psychogenic illness. But it throws water on the dominant weapon theory and leaves the clear implication that the cause could be psychological. 

Why Is This So Hard to Accept?

Those who study mass psychogenic illnesses are quick to point out that the people affected are experiencing real physical symptoms. They are not imagining their complaints. So, why is this explanation so difficult to accept?

First, people often mistakenly believe they are being accused of mental illness. This is wrong. The very fact that the symptoms typically start with an index case and spread to larger and larger groups of people suggests it is not a mental illness. Psychological disorders are typically not catching. The culprit is not inside the people; it stems from the situation the people are in. In many cases, mass psychogenic illness can be understood as a response to a stressful situation. The compulsive dancers of the Middle Ages were dealing with poverty, war, plagues, and famine. The school children with rashes were responding to a uniquely scary period of bioterrorism fears, and the U.S. embassy staff in Havana were posted in a Russian-backed country with whom we have a long history of conflict. 

Part of the confusion may simply be language. When we say that mass psychogenic illness is a psychological phenomenon, it does not imply that it is a psychological problem or mental illness. When a crowd at a sporting event turns ugly and fights break out, the resulting riot is a mass psychological event with dangerous ramifications, but there is no reason to believe the participants are mentally ill. Perfectly normal people do many things together—both good and bad—as a function of group psychology. 

Second, once it reaches “epidemic” proportions, people band together, creating an advocacy group in search of someone to blame. The media play an important role in the process. Criterion 2 above states that “there must be a pre-existing social connection between two or more of the affected people.” In the Middle Ages, that meant a direct social connection, and as a result the dancing mania moved relatively slowly through Europe. In today’s world, word of an outbreak can move quickly over long distances. The girls in the 9/11 rash case were interviewed on local television, and the news spread rapidly. Similarly, the spy-versus-spy aspect of Havana Syndrome case spurred considerable media attention. There is a shortage of good research on the role of the media in mass psychogenic illness, but a 2005 preliminary study of past outbreaks suggested that media coverage could facilitate the spread of school-based psychogenic illnesses such as the 9/11 rash case (Vasterman et al. 2005). Media coverage can also build an advocacy group for the victims. When the 9/11 rash hit Quakertown, Pennsylvania, 1,000 parents showed up for a meeting with the school superintendent (Talbot 2002). It’s easy to imagine how difficult that meeting must have been for the school officials. 

Third, we are no longer in an age—if we ever were—when people passively accept the diagnoses of medical professionals. Rather than leaving the prescribing of medicines up to our doctors, we watch endless drug commercials on television and are urged to “ask your doctor if ______ is right for you.” Getting good health services in the United States often requires being very assertive, and almost everyone has a story about having to fight with insurance companies to get coverage. It is not surprising that people would organize and advocate for a preferred diagnosis that implicates some villain rather than the more nuanced explanation of a group psychological effect. 

The Long COVID Example

The newly emerging diagnosis of long COVID provides another example of the rejection—or neglect—of possible psychological factors. In March 2021, Adam W. Gaffney, a pulmonary critical care physician and assistant professor of medicine at Harvard Medical School, published an article in STAT titled, “We Need to Start Thinking More Critically—and Speaking More Cautiously—about long Covid” (Gaffney 2021). Many people have described very disturbing cases of chronic symptoms, including palpitations, headaches, severe fatigue, difficulty sleeping, hair loss, and brain fog that they attribute to the lasting effects of coronavirus infection. But Gaffney pointed out that there is no clear definition of long COVID and that some of the people who self-identify as “long haulers” appear never to have been infected with the SARS-CoV-2 virus. In an influential article, science journalist Ed Yong (2021) reported on a survey of long haulers showing that two thirds of them had negative coronavirus antibody tests, suggesting that they may not ever have been infected. Some of those tests could be false negatives, but Gaffney argued that this was a highly unlikely circumstance that undermined the conclusion that COVID-19 was the cause of the symptoms. Without question, people who suffer severe bouts of COVID-19 often have long recovery times (Ekbom et al. 2021), but the large array of symptoms reported by people who had mild or completely asymptomatic cases of COVID-19 suggests that other factors may be involved.

Gaffney did not mention mass psychogenic illness by name, but many of the conditions that encourage psychogenic illness are present in long COVID. Living through the pandemic has been extremely stressful for all of us. A study based on data collected by the U.S. Census Bureau found that in the first months of the pandemic, rates of depression and anxiety tripled in comparison to the previous year (Twenge and Joiner 2020). News about COVID-19 has saturated our lives, and the long COVID phenomenon has received substantial coverage. In addition, today’s highly competitive medical services industry has been quick to respond. A recent article in Becker’s Hospital Review identified sixty-six hospitals in the United States that have opened long COVID clinics (Carbajal and Gleeson 2022). All these factors serve to validate the long COVID diagnosis and encourage the attribution of a wide collection of symptoms to the lasting effects of coronavirus infection. 

As in the Havana Syndrome case, COVID-19 long haulers and their supporters did not react favorably to Gaffney’s article. Before commenting was quickly turned off, several long haulers weighed in. A commenter named Rivka wrote “Throughout history there is always a faction of medical professionals who will take it upon themselves to dismiss a physical illness as ‘all in your head.’” To me, Gaffney had shown considerable compassion for the long haulers, writing, “but make no mistake: the suffering described by long Covid patients is debilitating and real.” Yet the response to the suggestion that psychology might be part of the explanation was fast and harsh. 

Why Does This Matter?

In 2018 and 2019, the Journal of the American Medical Association published two MRI studies of U.S. embassy personal who suffered symptoms attributed to Havana Syndrome. The authors concluded that the scans of the embassy workers’ brains showed significant differences when compared to normal controls. As Baloh and Bartholomew (2021) reported, the studies were severely criticized for bias, poor methods, and unjustified conclusions. Nonetheless, media coverage of the studies reinforced the idea that the embassy workers had suffered brain damage. 

Unfortunately, if the mass psychogenic illness interpretation is correct, the JAMA studies and media coverage suggesting the presence of brain damage may create obstacles to recovery. People who think they have suffered brain injury are likely to assume they will be permanently affected and to attribute any symptoms they experience to their damaged brains. In contrast, acceptance of the psychogenic interpretation could facilitate recovery. Baloh and Bartholomew (2020) sum it up well: “The symptoms that began in Cuba as a result of social paranoia and insect sounds exemplify the power of belief. That same power holds the key to their recovery” (188). 

Note

1. I am just reporting results for “systematic” reactions here. Local adverse effects at the injection site were reported separately and were generally less common. 

References

Associated Press. 2017. Mystery of sonic weapon attacks at US Embassy in Cuba deepens. The Guardian (September 14). Available online at https://www.theguardian.com/world/2017/sep/14/mystery-of-sonic-weapon-attacks-at-us-embassy-in-cuba-deepens. 

Baloh, Robert W., and Robert E. Bartholomew. 2020. Havana Syndrome: Mass Psychogenic Illness and the Real Story behind the Embassy Mystery and Hysteria. Cham, Switzerland: Springer Nature.

Carbajal, Erica, and Cailey Gleeson. 2022. 66 hospitals, health systems that have launched post-Covid-19 clinics. Becker’s Hospital Review (February 9). Available online at https://www.beckershospitalreview.com/patient-safety-outcomes/13-hospitals-health-systems-that-have-launched-post-Covid-19-clinics.html. 

Clements, C. John. 2003. Mass psychogenic illness after vaccination. Drug Safety 26(9): 599–604. 

Cleveland Clinic. N.d. Stress: Ways to ease stress. Available online at https://my.clevelandclinic.org/health/articles/8133-stress-10-ways-to-ease-stress. 

Esterianna, Leah, and Richard the Poor of Ely. N.d. Dancing mania. The Letter of Dance, 3. Available online at http://www.pbm.com/~lindahl/lod/vol3/dancing_mania.html.

Ekbom, E., R. Frithiof, Öi Emilsson, et al. 2021. Impaired diffusing capacity for carbon monoxide is common in critically ill Covid-19 patients at four months post-discharge. Respiratory Medicine 182 (April): 2020–22. 

Gaffney, Adam W. 2021. We need to start thinking more critically—and speaking more cautiously—about long Covid. STAT (June 23). Available online at https://www.statnews.com/2021/03/22/we-need-to-start-thinking-more-critically-speaking-cautiously-long-Covid/. 

Haas, Julia W., Friederike L. Bender, Sarah Ballou, et al. 2022. Frequency of adverse events in the placebo arms of Covid-19 vaccine trials: A systematic review and meta-analysis. JAMA Network Open 5(1): 1–15. 

Harris, Shane, and Missy Ryan. 2022. CIA finds no “worldwide campaign” by any foreign power behind mysterious ‘Havana syndrome.’ The Washington Post (January 20). Available online at https://www.washingtonpost.com/national-security/cia-havana-syndrome-investigation-russia/2022/01/20/2f86d89e-795c-11ec-bf97-6eac6f77fba2_story.html. 

Kirsch, Irving. 2000. Are drug and placebo effects in depression additive? Biological Psychiatry 47(8): 733–35. 

Oppmann, Patrick. 2022. Cuba calls on Biden to restaff embassies, normalize relations following CIA ‘Havana syndrome’ report. CNN (January 26). Available online at https://www.cnn.com/2022/01/26/americas/cuba-us-embassies-cia-havana-syndrome-report-intl/index.html. 

Page, Lisa A., Catherine Keshishian, Giovanni Leonardi, et al. 2010. Frequency and predictors of mass psychogenic illness. Epidemiology 21(5): 744–47.

Swanson, Ana, and Edward Wong. 2020. Report points to microwave “attack” as likely source of mystery illnesses that hit diplomats and spies. The New York Times (December 5). Available online at https://www.nytimes.com/2020/12/05/business/economy/havana-syndrome-microwave-attack.html.  

Talbot, Margaret. Hysteria hysteria. 2002. The New York Times (June 2). Available online at https://www.nytimes.com/2002/06/02/magazine/hysteria-hysteria.html. 

Twenge, Jean M., and Thomas E. Joiner. 2020. U.S. Census Bureau-assessed prevalence of anxiety and depressive symptoms in 2019 and during the 2020 COVID-19 pandemic. Depression and Anxiety 37(10): 954–56. 

United States Congress. 2021, S.1828 – 117th Congress (2021–2022): Havana Act of 2021 … (October 8). Available online at https://www.congress.gov/bill/117th-congress/senate-bill/1828. 

United States Senate Committee on Foreign Relations. 2018. Attacks on U.S. diplomats in Cuba: Response and oversight: United States Senate Committee on Foreign Relations (January 9). Available online at https://www.foreign.senate.gov/hearings/attacks-on-us-diplomats-in-cuba-response-and-oversight-010918.

Vasterman, Peter, C. Joris Yzermans, and Anja J.E. Dirkzwager. 2005. The role of the media and media hypes in the aftermath of disasters. Epidemiologic Reviews 27: 107–14. 

Waller, John. 2009. A forgotten plague: Making sense of dancing mania. Lancet 373(9664): 624–25. 

Yong, Ed. Long-haulers are redefining covid-19. 2021. The Atlantic (July 30). Available online at https://www.theatlantic.com/health/archive/2020/08/long-haulers-Covid-19-recognition-support-groups-symptoms/615382/.