Abstract
Keywords
Society's understanding of mass psychogenic illness (MPI) has evolved over the centuries. These events were referred to as “mass hysteria,” a term that has fallen out of favor because of its derogatory implications toward women.
1
MPI is a functional neurologic symptom disorder, also known as mass sociogenic illness or conversion disorder, where an outbreak of an illness is incompatible with a recognized pathophysiology and neurologic disease.2,3 The process of diagnosing and treating MPI can be notoriously difficult because of extensive evaluation and testing required for a diagnosis. Previously regarded as a diagnosis of exclusion, MPI is now considered a “rule-in” diagnosis by the
Episodes of MPI involve groups of people who are simultaneously affected with a similar presentation of a functional neurologic symptom disorder. MPI can involve a wide variety of symptom presentations. The diagnostic criteria for functional neurologic symptom disorder per the
1. One or more symptoms of altered voluntary motor or sensory function; 2. Clinical findings provide evidence of incompatibility between the symptom and recognized neurological or medical conditions; 3. The symptom or deficit is not better explained by another medical or mental disorder; 4. The symptom or deficit causes clinically significant distress or impairment in social, occupational, or other important areas of functioning or warrants medical evaluation. 2
MPI can present as a functional movement disorder with symptoms such as tremor, dystonia, myoclonus, gait disorder, Parkinson-like movements, tics, or paralysis. 5-7 Tics have been reported in only 2% of cases of functional movement disorder not associated with MPI. 6 Some of the most common presentations of functional movement disorder include tremor and dystonia, whereas tics are uncommon.6,8,9 Around 5% of patient referrals to neurology clinics involve a diagnosis of functional neurologic symptom disorder, although the true prevalence of MPI remains unclear. 2 Tracking the number of MPI cases involving functional movement disorder and tics is even more challenging. At times, MPI outbreaks are clearly tied to an event or exposure, but often inciting causes can be nebulous. Some literature supports the idea of an “index case” or a nidus for the spread of the event.10,11
Many cases of documented MPI occur in school-based settings and predominantly involve females.2,3,12 School-based events are possibly common because of the cohort's proximity to one another, shared exposures, similar cognitive and developmental maturity levels, and presence of a hierarchical structure. 12 The occurrence of MPI in LeRoy, NY, became a pivotal example of a less common form of MPI with school-aged individuals initially presenting with a movement disorder taking the form of abrupt-onset tics.
This study presents demographics, laboratory, and ancillary testing results for 16 patients involved in the 2011-2012 outbreak of MPI in LeRoy, NY, treated at Dent Neurologic Institute. The patients presented sequentially and at first seemingly unrelated to each other. Each patient underwent an individual assessment and workup that was medically appropriate for their presenting symptoms and situation. The goal is to report on this unique event, provide rationale for the diagnosis, and highlight the challenges of diagnosing and treating MPI in the age of modern media.
Methods
Study Design and Population
A retrospective chart review compiled demographic information, medical history, and laboratory/ancillary test results for patients presenting with abrupt-onset tics and diagnosis of MPI. From 2011 to 2012, 19 individuals were identified, 16 of whom were formally evaluated at Dent Neurologic Institute. Three other individuals were scheduled but did not show for appointments and were not evaluated.
Statistical Methods
Frequencies and proportions were used to describe the distributions of categorical variables, whereas means and standard deviations were used for continuous variables. Normative laboratory values were recorded using various testing sites. If abnormal results fell outside of normal ranges, they were recorded and compared to established standards. These values were categorized into abnormal interval percentiles (5%, 10%, 15%, and 20%). All statistical analysis was completed using SAS (version 9.4, Cary, NC).
Standard Protocol Approvals, Registrations, and Patient Consents
The WCG institutional review board (IRB) approved a waiver of Health Insurance Portability and Accountability Act (HIPAA) authorization for use and disclosure of protected health information for this study on July 11, 2024. WCG institutional review board's IRB Affairs Department provided a determination of Exemption under 45 CFR§ 46.104(d)(4).
Data Availability
No individual participant data will be publicly available to protect patient privacy because of the previous very high-profile nature of this event. The data were held for 10 years to allow the patients time to become adults.
Results
Fifteen of the 16 patients diagnosed with MPI attended LeRoy Junior-Senior High School, aged 13-19 years and one was a 36-year old relative of a patient (mean age 15.2 ± 1.8 years). Fifteen identified as female and 1 as male. Symptoms started between September 10, 2011, and December 5, 2012. One patient had a prior diagnosis of Tourette syndrome (diagnosed 2005) and another tic disorder (diagnosed 2010). Patients presented to the Dent Neurologic Institute between October 27, 2011, and December 20, 2012. The mean time from MPI symptom presentation to first appointment was 21.8 ± 23.4 days. At consultation, patients were on a mean 1.8 ± 1.6 medications. The mean number of office visits per person was 9.8 ± 8.7. Three patients continued to be seen at Dent Neurologic Institute after MPI symptoms resolved for migraine, Tourette syndrome, anxiety, and general neurologic care. Patient demographics and medical history are in Tables 1 and 2. Almost all patients presented at consultation with notable social stressors. To maintain privacy, generalized descriptions of stressors are provided in Table 3. Older patients presented with symptoms first, and younger patients followed (Figure 1).
Age at onset of symptom presentation. *36-year-old outlier not included in figure.
Demographics.
Abbreviation: MPI, mass psychogenic illness.
Age at consult: 36-year-old outlier not included in statistics.
Visits included only those pertaining to MPI symptoms.
Medical History.
Abbreviations: ADHD, attention-deficit hyperactivity disorder; OCD, obsessive compulsive disorder.
Social Stressors.
All patients presented with abrupt-onset vocal and motor tics, except 1 with motor tics only. Many patients developed additional symptoms, progressing through 4 distinct neurologic presentations often in the same order. All patients started with tics, then several followed with syncope, psychogenic nonepileptic seizures, and/or migraines (Table 4). Not all patients experienced all 4 of these symptoms. Both patients with preexisting movement disorders experienced notable exacerbations of their tics.
Symptoms.
Abbreviation: PNES, psychogenic nonepileptic seizures.
All laboratory results are from the patients’ first visit at Dent Neurologic Institute or when testing was first medically necessary. Table 5 includes the abnormal laboratory testing and a comparison to standard normal ranges. Table 6 includes ancillary test results: brain MRI, electroencephalography (EEG sleep deprived and epilepsy monitoring unit), electrocardiography (ECG), head computed tomography (CT), and echocardiogram. Thirteen of 16 patients had brain MRI. Seven of 13 tests were normal; 4 of 13 were normal variants; and 2 of 13 were abnormal. Five patients completed sleep deprived EEGs, and two completed long-term monitoring (epilepsy monitoring unit). Results included normal EEG (n = 7 of 7), normal ECG (n = 3 of 3), normal head CT (n = 2 of 2), and normal echocardiogram (n = 2 of 2) findings.
Abnormal Laboratory Results.
Abbreviations: ALT/SGPT, alanine aminotransferase / serum glutamic-pyruvic transaminase test ; ANA, antinuclear antibody; AST/SGOT, aspartate aminotransferase / serum glutamic-oxaloacetic transaminase test; IgE, immunoglobulin E; IgG, immunoglobulin G; IgG4, immunoglobulin G4; IgG2, immunoglobulin G2; IgM, immunoglobulin M; RBC, red blood cell; WBC, white blood cell.
*All abnormal reported results were compared to established standards and categorized into abnormal interval percentiles (5%, 10%, 15%, and 20% either above or below normal range).
Ancillary Test Results.
Abbreviations: CT, computed tomography; ECG, electrocardiogram; EEG, electroencephalography; MRI, magnetic resonance imaging.
Discussion
MPI is a poorly understood phenomenon with a scarcity of evidence-based literature, because of the unpredictable nature of its evolution and resolution. This is especially true for functional movement disorder involving tics. In this outbreak, each patient was treated as an individual taking into account their unique symptoms and history. True to traditional MPI presentations, there was a prevalence of female and school-aged patients.2,3,12 Symptom onset did follow an age hierarchy, affecting high school before middle school students (Figure 1). Two patients with preexisting movements disorders presented with an exacerbation of tics, and one also experienced syncopal/psychogenic nonepileptic seizures events. Autism spectrum disorder (ASD) can also co-occur with functional neurologic symptom disorder, but no patients presented with ASD in this cohort. 13
MPI often starts after a life stressor. 14 Several patients presented notable life stressors, although some life stressors were omitted to maintain privacy (Table 3). The media were forthcoming with details regarding traumatic life events for the children that may have exacerbated symptoms; examples can be seen online. This was noted for patients seen at Dent Neurologic Institute and children who were not Dent Neurologic Institute patients. Interestingly, there was a notable “la belle indifférence” with most patients regarding their symptoms. This attitude of indifference by patients toward their condition is commonly associated with functional neurologic symptom disorder. 2
Not all laboratory or ancillary tests were acquired for every patient, as they were not deemed medically necessary. In total, 32 of 64 test types yielded abnormal results. However, a majority of these results were marginally abnormal. Many laboratory tests falling 5% to 10% out of the accepted clinical range were considered normal variants depending on the type of measure, and those falling in the >15% to 20% range were more clinically concerning.
Of the abnormal test types, 5 of 32 included qualitative tests involving toxicology screen, urine analysis, antinuclear antibody (ANA) test, Streptozyme test, and Lyme Western blot IGM (Table 5). There were 13 of 32 quantitative laboratory types that deviated <10% from normal ranges, which is typically medically acceptable including WBC, RBC, lymphocytes, neutrophils, chloride, anion gap, blood urea nitrogen, glucose, IgG, IgG2, IgG4, copper, and free T3 (Table 5).
The following results had a >10% deviation from normal ranges. One eosinophil level was elevated by >20%, which could be indicative of allergies. Two elevated erythrocyte sedimentation rates were <5% and >20%, elevated which could be from inflammation, allergies, infection, or even trauma. One AST was decreased by >20%, which was repeated and was normal. Three ALT results were decreased by <5%, >5%, and >20%. Low ALT levels can indicate a vitamin B6 deficiency or normal variation. 15 Nine patients had low alkaline phosphatase test results; however, the Cleveland Clinic defines the normal range as 44-147 international units per liter (IU/L), and all values fell within this range. 16 One patient had an elevated folate level by >20%, which is a normal variant. Vitamin D was decreased by >20% in 4 patients; their deficiencies were treated. Three patients were positive for benzodiazepine on toxicology screens; all were prescribed this by Dent Neurologic Institute or an outside provider for singular use to facilitate blood draw.
Two IgE levels were elevated >20% from normal, which may be due to allergies. One IgM was elevated by >20%, which could be indicative of chronic infection or allergies. One patient had an elevated ANA titer of 1:160. Guidelines state that this can be a normal variant and that an ANA of 1:160 is not necessarily indicative of autoimmune disorder. A prior study also found that of healthy individuals, 5% had ANA titers of 1:160. 17 One patient had a 1:80 ANA titer, which is medically acceptable. Inflammatory changes such as infection or allergies can also elevate ANA transiently.
Five patients had elevated
Two thyroid-stimulating hormone (TSH) levels were decreased by >20% from normal, and another was elevated by >20%. One patient had a preexisting diagnosis of hypothyroidism and was treated with levothyroxine, which decreased the patient's TSH levels. This patient adjusted their medication with their pediatrician, which did not resolve their symptoms. The second patient had a low TSH and was asked to repeat this test and see an endocrinologist. This patient's symptoms spontaneously resolved prior to treatment for this issue. A third patient had an elevated TSH and a preexisting diagnosis of hypothyroidism on levothyroxine. They were instructed to adjust their medication accordingly with their primary care provider. This did not resolve their symptoms.
Three patients yielded elevated antistreptolysin O (ASO) titers. Results did not meet criteria for clinical abnormality per the National Institute of Mental Health's guidelines for ASO titers (>400 IU/mL).
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One patient had a DNase result elevated by >20% and a positive Streptozyme test, which indicates an immune response to a past infection of
The majority of the ancillary test results were normal. All EEG, ECG, CT head, and echocardiogram tests yielded normal results (Table 6). Brain MRI had 4 normal variants and 2 abnormal results. The normal variant findings included cerebellar tonsillar ectopia; sinus polyp changes in 2 patients, one of which had a persistent trigeminal artery; and the last had a hyperintensity adjacent to the frontal lobe suspicious for artifact. These findings were incidental and did not explain the patients’ movement disorder. Abnormal brain MRI results in 1 patient included a moderate amount of white matter change in the centrum semiovale and juxtacortical areas bilaterally as well as reversal of the lordotic curvature of the spine. However, this patient had a history of illicit substance abuse years before symptom presentation, which could have accounted for these abnormalities. This patient was lost to follow-up for repeat imaging, but their symptoms resolved spontaneously. The second abnormal MRI revealed a persistent T2 abnormality in the midbrain and pons suggestive of a hypertensive episode in utero or postnatally. This patient had 4 follow-up MRIs between 2013 and 2017 that remained unchanged, and their symptoms eventually resolved.
The results of this study reveal that some patients did have abnormal results on laboratory and brain MRI testing. The results were incidental or within reason for the patients’ clinical presentation and history. The diagnosis of MPI now follows a “rule in” method where a psychological stressor is not necessary for diagnosis. It does require evidence showing incompatibility with recognized neurologic diseases; therefore, a differential diagnostic approach was pursued for each patient. 2 As organic causes were treated or ruled out and patients all exhibited almost identical symptomatology, a MPI diagnosis became evident. Furthermore, the laboratory, imaging, and ancillary test results did not support a cohesive, unifying pathophysiology for patients’ symptoms other than MPI.
Other physicians refuted MPI diagnosis and endorsed a mass presentation of pediatric autoimmune neuropsychiatric disorders associated with streptococcus infections (PANDAS). PANDAS result from group A streptococcal infection that purportedly precipitate obsessive compulsive tendencies, anxiety, and tics. 21 During the height of the LeRoy phenomenon, there was a collaborative investigation by the New York State Department of Health, New York State Office of Mental Health, LeRoy Central School District, and Genesee County Health Department to examine infectious or environmental etiologies of this outbreak. 22 This study found that “none of the cases [met] the PANDAS criteria” for diagnosis. 22 Although 3 patients had elevated ASO blood titers that indicate group A streptococcal antibodies, none met the diagnostic criteria for PANDAS per the National Institute of Health's (NIH’s) standards (>400 IU/mL).21,22
In addition, the Dent Neurologic Institute and New York State Department of Health also partnered with the NIH to have Drs Susan Swedo and Mark Hallett provide free third-party evaluations for any affected patients. 23 Dr Swedo, the neuroscientist who discovered PANDAS, evaluated 2 patients from Dent Neurologic Institute and both were confirmed negative. Dr Swedo gave an interview to a local newspaper regarding PANDAS as a possible diagnosis, stating that it is “unlikely” this was a PANDAS outbreak. 24 Noting that if there was a mass PANDAS outbreak, male cases should outnumber female cases by 3 or 4 to 1, so there should have been “40 to 50 boys exhibiting symptoms” instead of just one male. 24 The University of Rochester Movement Disorder Clinic also assessed 2 patients and agreed with the MPI diagnosis.
There were beliefs that vaccinations or environmental factors contributed to the incident. The New York State Department of Health collaborative study found no temporal associations with symptom onset and vaccine administration. 22 The New York State Department of Health also formally investigated possible toxic exposure. This was driven by public accusations by Erin Brockovich and associates who came to LeRoy and met with news and media outlets. 25 There was speculation that this episode was related to a Superfund Site from the 1970 derailment of a train carrying toxic chemicals.22,26 The New York State Department of Health and the Environmental Protection Agency (EPA) determined that contamination from this site did not spread and/or cause this event. In addition, the Monroe County Water Authority tested water from the school with the Genesee County Health Department (GCHD) and found no contaminants. 22 The Genesee County Health Department collected additional water samples from the school that similarly found nothing. After several very costly studies, no environmental cause was found. Overall, it was concluded that there was no contamination at the school.
This confirmation by the New York State Department of Health ultimately strengthened the diagnosis of MPI, as PANDAS and contamination from the surrounding area were ruled out. The likelihood of an infectious or environmental cause was highly unlikely because of the demographics of the cohort. It seemed improbable that healthy, young girls were the majority of people to demonstrate symptoms, whereas vulnerable populations such as infants, elderly individuals, or residents adjacent to the school were unaffected. Despite findings of common transient infections found in Western New York during the winter months on laboratory investigation, there was no unifying illness to support an infectious etiology.
Relaying the diagnosis of MPI can be difficult because of a myriad of reasons, such as a patient's rejection of the diagnosis or perception that the physician is accusing them of intentionally exacerbating symptoms. Furthermore, it has been suggested that a physician's own rebuke of a psychological diagnosis can hinder patient recovery. One study assessing patient acceptance of psychogenic nonepileptic seizures diagnosis found that being taken seriously by their healthcare provider was integral to acceptance.27 A previous study also reported that a patient's perception of treatment efficacy from their physician was the best indicator of positive outcomes for functional movement disorder. Poor outcomes were associated with patient dissatisfaction with the physician. 9 Although a differential diagnosis is necessary, a consensus agreement between monitoring physicians, the patients, and family on the MPI diagnosis is critical to recovery.
Appropriate testing to rule in a MPI diagnosis can bolster confidence between the practitioner and patient. Statements made to patients suggesting that they were feigning symptoms were noted to increase exacerbations. Not acknowledging the patients’ distress can lead to worsening symptoms, as well as evolution of the condition beyond the initial presentation of tics. Acknowledging and affirming the patient's illness and struggle was found to aid in patient recovery as opposed to adversarial speech or attitude.
There is a theory that an index case is the nidus for the initiation of MPI. This episode included individuals with previous diagnoses of movement disorders, but they presented later, and it is unclear if these patients could be considered an index case. In this cohort, older patients exhibited symptoms followed by young patients in a hierarchical pattern (Figure 1). The progression through different motor symptoms were not identical, but patients followed a similar pattern beginning with tics, then syncope, psychogenic nonepileptic seizures, and finally migraines. It should be noted that not all patients experienced every stage of progression, but each individual symptom was not exhibited unless prior symptoms occurred.
This progression, especially to migraine at the conclusion, may have been confounded by the treating neurologist's board certification and specialty in headache medicine. Each patient diagnosed with migraine met ICHD-II criteria. Migraine is clearly not a functional neurologic symptom disorder. It was included as a symptom for this article as it was notable that 69% of patients developed new-onset migraine as their recovery progressed. Prior functional neurologic symptom disorder occurrences have recorded migraine as a comorbidity, but not as a symptom. 28 Development of migraine in women at this age is common, which could account for some of the cohort; however, it is interesting to note this mind and body connection. 29 An alternative etiology could be a diathesis-stress model, which purports that individuals have underlying genetic predisposition that remains dormant unless activated by an outside stressor. 30
This episode of MPI may have been further complicated by the issue of extensive diagnostic evaluation and treatment. Excessive treatment is defined as not benefiting the patient or potentially causing harm that outweighs patient benefit. 31 The overtreatment of medical conditions can be harmful for patients and result in undesirable outcomes, especially with psychogenic illness. In this event, overtreatment was a concern as attention to the condition tended to exacerbate symptoms. However, underattention and disregard for patient symptoms similarly exacerbated them. In addition to potentially causing harm, overtreatment results in excess use of health care resources. Some patients also had frequent emergency department visits because of syncope and seizure. The relationship between over- or undertreatment and psychogenic illness should be further studied to improve treatment outcomes and optimize health care use while providing support without compromising patient care. Providers face a conundrum navigating diagnostic pathways and treatment without over- or underattention because both can worsen symptoms. This event is suspected to have persisted because of constant media attention causing distrust for the supporting medical professionals.
When a patient was in proximity to others experiencing tics, the patient was often noted to have a symptom exacerbation that visually resembled the person they witnessed. Given this challenge, removing a patient from school for an extended period of time was found to successfully decrease the frequency and severity of symptoms. A proposed biological explanation for MPI is the mirror neuron system. The mirror neuron system is a more recent discovery within the field of neuroscience. The original mapping of the mirror neuron system occurred with work in the macaque monkey, a close evolutionary relative to humans. 32 It has been demonstrated that the mirror neuron system is tied not only to brain centers that control movement but also behaviors that are related to emotions. 33 The implication of the mirror neuron system in the control of both motor and emotional behaviors opens a new door into MPI research. It is also possible that the mirror neuron system is not just responsible for behavior mimicry and empathy but for the spread of MPI. In this case, the motor and vocal tics were almost identical to each other. This assisted with the process of diagnosis given it is rare for 16 people to present with visibly similar abrupt-onset tics concurrently. Future studies might examine functional neuroimaging for functional movement disorder patients with an intent to better understand the role of mirror neurons.
LeRoy continues to be a landmark case of MPI and is still referenced to this day. 34 As reported MPI cases continue to grow, there is an increased need for research in this area. There remains a lack of literature on the diagnosis, evolution, and resolution of MPI as well as challenges that health care professionals face treating this disease in the modern age of technology. This was evident in a recent suspected MPI case of “TikTok tics” internationally, which is an excellent example of how mirror neurons may play a role in the initiation and spread of MPI. 35 TikTok is a social media platform where creators share video clips of themselves, often meant for replication. Thousands of young people in 2021 reported functional tics after viewing popular TikTok creators showing their own tics.35,36 Given that present literature has suggested an increase in functional movement disorder prevalence since the COVID-19 pandemic, understanding proper care is of the utmost importance. 37
Within our cohort, patients were anecdotally noted to have symptom improvement when transitioned to at-home learning and when media coverage of the children decreased. Similarly, patients were anecdotally noted to have exacerbated symptoms when they were around other children who exhibited vocal and motor tics and when media coverage was increased. As media coverage eventually subsided, symptoms related to MPI resolved completely for all patients.
The present study is limited because of its retrospective nature. Many patients had common laboratory and imaging studies performed, but these were done only if indicated. Medical care was individualized and followed standard practices. For example, some patients did not develop psychogenic nonepileptic seizures, so an EEG was not indicated. Other patients’ symptoms resolved quickly and did not require further testing or follow-up. This was limited also as not all patients in the cohort were evaluated at Dent Neurologic Institute.
This retrospective evaluation supported the diagnosis of MPI in 16 patients evaluated with the onset of functional movement disorder. Laboratory testing, imaging, and ancillary studies did not support an alternative cause for symptoms. Third-party testing for toxins, vaccines, infectious exposure, and autoimmune disorders did not yield an alternative cause. This case exemplifies the need for further evidence-based research on MPI and also illustrates the challenges of treating and managing MPI in the age of mass media.
The treating clinician must partner with the patient and family to facilitate wellness. Treatment for this diagnosis requires cross-discipline collaboration for patient support and recovery. In this case, the treating neurologists struggled to find interdisciplinary support in the community. This could be due to stigma of MPI or overburden in medical practice, as patients with functional neurologic symptom disorder require more involved care.
LeRoy was truly a landmark case, as one of the first episodes of MPI where the media documented and influenced the evolution and progression of this MPI event. The world followed the patients in real time through diagnostic and treatment efforts, provoking opinions and suggestions that affected recovery. Learning from previous experience is valuable to prepare future clinicians to diagnose and support patients during these exceptional events. Education for medical professionals on proper engagement with the media to protect both provider and patient safety is critical, especially when children are involved.
Footnotes
Acknowledgments
ORCID iD
