What Is Mass Psychosis? Meaning, Symptoms, And History

The phrase mass psychosis often conjures the images of widespread panic and mayhem seen in many movies and TV shows. These representations tend to be exaggerated, but the phenomenon of “contagious” symptoms associated with stress and anxiety is real. Understanding the mass psychosis meaning, the updated terms used to describe this effect, and how it can come about can provide insights into human psychology and social behavior. If you’ve been affected by this phenomenon or want to build emotional resilience, working with a therapist online or in person may be helpful.

What is mass psychosis?

The American Psychological Association defines this phenomenon as “the spontaneous outbreak of atypical thoughts, feelings, or actions in a group. Manifestations may include psychogenic illness, collective hallucinations, and bizarre actions.” MPI can come in a few different forms, such as mass anxiety hysteria or mass motor hysteria, depending on the symptoms.

Mass psychogenic illness may be seen as a domino effect: A few people in a group experience typically mild but unusual and sudden symptoms (such as nausea, dizziness, headache, or a rash), prompting heightened anxiety and awareness in others nearby. Especially within tight-knit communities or tense situations, a sense of unease can spread. This environment might lead to more individuals developing some of the same symptoms, even without any shared physical illness or contagion being present.

If you’re concerned about your mental health, support is available. You can connect with a mental health professional online.

Mass psychosis vs. mass hysteria vs. sociogenic illness

Today, mental health professionals recognize that certain terms can be stigmatizing—including forms of “hysteria.” That’s why modern mental health experts typically prefer the term "mass psychogenic illness" (MPI) or sociogenic illness for this phenomenon rather than mass hysteria or mass psychosis. These accepted alternatives acknowledge the psychological component of the effect without diminishing the authenticity of the symptoms experienced. Language matters and can subtly shape our perceptions and potential responses.

Famous historical cases of MPI

Since there’s no test for MPI and symptoms are often nonspecific, it can be difficult to “diagnose” it with accuracy. That said, throughout history and through to the present day, there have been many recorded instances of what now may be interpreted as suspected MPI, both in the US and many other countries around the world. Some examples include:

• “The dancing plague" in the Middle Ages in Europe, when groups of people would compulsively dance for days or weeks on end, sometimes reportedly reaching utter exhaustion and even death
• A girls’ school in Germany, plus others in Malaysia, Afghanistan, England, Tanzania, across the US, and more throughout history, where symptoms like dizziness, fainting, itching, or laughter attacks spread among the students 
• The Salem witch trials, when accusations of witchcraft spread among communities as an explanation for why some people experienced symptoms like convulsions, leading to mass public support for the execution of the alleged witches, who were typically innocent women who did not fit social norms

There have also been many documented instances of this phenomena in a different form, where an unfounded collective fear of a perceived threat spreads through a population. The moral panic in the US in the 1980s, known as the “satanic panic,” is one example. It started with the publishing of a now-discredited book in which the author proposed that she experienced “satanic ritual abuse” as a child. This book and media coverage of it led to a widespread panic and 12,000 reported cases of such abuse in the US alone, none of which were ever substantiated.

Considering the historical context of each suspected instance of MPI can be important. These events may serve as examples of how fear, stress, social pressure, and social unrest can fuel unusual behaviors and beliefs in a population.

MPI today

Even today, there are sometimes reports of MPI symptom clusters within schools, workplaces, or communities. There have also been reports of MPI spreading solely via social media. This development has prompted researchers who published a study in the European journal Brain to propose the term “mass social media-induced illness” to describe this form of MPI.

Common symptoms reported in mass psychogenic illness events

There may not be a single set of symptoms associated with most outbreaks of MPI events, as many researchers have described its protean nature. That said, some examples of common symptoms often reported in instances of MPI include the following.

Physical and neurological symptoms

Physical and neurological symptoms are usually noticed first. The following symptoms are common examples, though this list is not exhaustive:

• Muscle twitches
• Dizziness
• Shortness of breath
• Fainting
• Nausea
• Stomach pain

As one study puts it, physical psychogenic symptoms are usually spread “by sight and sound, whether on-site or via media, and are characterized by rapid onset and rapid remission.”

Emotional, cognitive, and behavioral symptoms

Physical signs are often accompanied by other symptoms that are emotional and cognitive, such as fear and free-floating anxiety. People might also appear to experience trance states, seemingly uncontrollable laughter, or other shared symptoms that are typically not harmful but can be concerning. These effects may be easily “spread” from one person to another via increased suggestibility. 

The authenticity of MPI symptoms

There’s often a tendency to write off MPI symptoms as bids for attention, but that view may be inaccurate and unfair. Experts believe that stress and anxiety may often be major players in mass psychogenic illness events, but the distress people feel is usually genuine. 

Just because experts can't pinpoint a specific, identifiable physical cause doesn't mean the symptoms themselves aren't real or disruptive to people's lives. Psychosomatic symptoms (physical complaints caused by mental health symptoms) or those caused by the nocebo or placebo effect can be just as distressing as those that stem from a diagnosable medical condition. If you’re concerned about mental health symptoms you may be experiencing, consider connecting with a therapist online.

What causes mass psychogenic illness?

The exact cause of mass psychogenic illness is not yet fully understood by psychology and social sciences experts. However, fear itself can be highly contagious. When we see someone experiencing something alarming, especially if the fear is unexplained, our own anxiety levels can escalate. This state of hyper-awareness may make us more susceptible to noticing or even developing similar symptoms ourselves, fueling the spread. Other contributing factors may be environmental, social, and psychological.

Environmental factors

It’s been suggested that certain environmental factors, such as high stress levels and tense environments, may increase the risk of MPI. For example, MPI’s “social contagion” effect may be particularly likely in “schools in which discipline is tight and accompanied with cultural strain between administrators and students.” Also, instances of MPI may sometimes be triggered by an unexpected new element in a normally predictable environment, such as a strange odor—which may cause sudden stress and psychosomatic symptoms even if it’s found to not be any kind of toxin. 

The broader sociopolitical environment may also play a role in MPI risk. Researchers in peer-reviewed studies, like a 2020 paper in Frontiers in Psychiatry, suggest that “MPI has often been observed during times of social oppression, uncertainty, rapid cultural change, and political violence.” The authors go on to propose that, “In the context of extreme oppression, MPI symptoms may function as a psychological defense or social expression of distress.”

Group dynamics and cohesion

Cases of MPI often (though not always) occur in populations that are already close-knit, such as students in a small school or residents in a small community. Such settings may amplify a certain human behavior or belief. It has also been proposed that the phenomenon of groupthink, when members of a cohesive group agree with a shared decision or conclusion due to peer pressure, may sometimes play a role.

Psychological vulnerabilities

Finally, not everyone may be equally vulnerable to mass psychogenic illness. For some, an existing mental health condition or severe strain could make them more susceptible to this kind of ripple effect. Others might be more sensitive by nature, potentially leading them to pick up on the emotions of a group more intensely.

The role of media in mass psychogenic illness

In some cases, exaggerated, sensationalized, or simply widespread media coverage may also contribute to the contagion of MPI symptoms. As mentioned above, social media may serve as a new vector for the spread of MPI symptoms. Also, contemporary sociology researchers have suggested that modern news coverage and talk in online spaces may sometimes amplify anxiety and encourage the spread of symptoms.

One example of how mass media might encourage or even trigger MPI is an episode of the Pokémon TV show that played in Japan in the 1990s, which involved a sequence of bright, flashing lights. In the days after the broadcast, over 12,000 children in the country reported experiencing symptoms like nausea and what appeared to be seizures. Social theory researchers believe that both media coverage of the symptoms and word of mouth about them in schools contributed to their wide spread.

Diagnosing mass psychogenic illness

Mass psychogenic illness is not a diagnosable condition per the DSM. It can also be difficult to identify, since symptoms tend to be generalized. When faced with clusters of unexplained symptoms, healthcare professionals may work with public health officials to conduct evaluations and tests to try and understand what's really going on. Ruling out underlying illnesses is often the first step.

Once medical possibilities have been ruled out, a diagnosis of mass psychogenic illness might be considered. In these cases, mental health professionals typically step in to provide support and help the affected individuals understand what they're experiencing. Separating the affected individuals from each other is often a first step toward recovery. Open communication and strategies to reduce stigma may mitigate the impact of mass psychogenic illness on individuals and communities. Strategies to manage future anxiety and stress can also become integral parts of the recovery process.

Who is most likely to be affected by MPI?

Affected persons in an MPI case can belong to any age group and identify as any gender. However, MPI is more often seen in young people, especially those who identify as girls or young women, though the reasons for reported differences in MPI symptoms based on gender remain unclear.

MPI vs. diagnosable mental disorders

MPI is not a diagnosable mental illness according to the most recent version of the Diagnostic and Statistical Manual of Mental Disorders, the DSM-5. Despite previous names like “mass psychosis,” MPI typically is not classified as a psychotic disorder because it does not actually involve any symptoms of psychosis or other signs of diagnosable mental health conditions.

That said, it’s possible for a person to be living with a mental health condition and also experience MPI. Certain conditions, such as anxiety disorders, trauma-related conditions, or stress-related conditions, might put a person at increased risk of being part of an instance of MPI.

Strategies for managing or reducing the risk of MPI symptoms

Even though symptoms typically resolve on their own without causing any serious or long-term complications, mass psychogenic illness can be distressing for all involved. The following strategies might help communities and individuals reduce the risk of MPI symptoms appearing or continuing to spread. For example, schools and communities might:

• Encourage the practice of self-care
• Teach techniques for reducing stress, like deep breathing
• Offer professional mental health support for students or residents
• Teach critical thinking skills to children and young people
• Provide clear and timely communication and reassurance if an MPI event does occur

Individuals may also benefit from reducing stress when possible. For instance, it might help to:

• Learn grounding techniques
• Practice gratitude
• Spend time in nature
• Set boundaries to protect personal autonomy
• Stay socially connected
• Set healthy limits on social media use and news consumption
• Seek professional mental health support as needed

Seeking mental health support

Working with a mental health professional is often part of recovery from MPI. They can help you address any lingering symptoms, process the experience, and work on building resilience and managing stress. If you’re also living with signs of a mental health condition, a therapist or psychiatrist can offer treatment options.

If you’re experiencing concerning physical symptoms, it may also be important to meet with your doctor to rule out any potential underlying conditions. If you’re experiencing a medical emergency, seek help from a healthcare professional immediately.

Getting mental health support online

You may be able to seek mental health care in person or online, depending on your needs and preferences. Some people prefer to meet with a therapist in person, white others might be interested in the convenience of virtual therapy sessions. 

With online therapy, you can meet with a licensed therapist remotely, from home or anywhere you have an internet connection and a personal device. Sessions can take place via phone, video, or live chat, depending on your preferences. Online therapy through a platform like BetterHelp also tends to be more affordable than traditional in-person sessions without insurance.

Is online therapy actually effective?

A growing body of scientific evidence suggests that many types of in-person therapy can often be similarly effective when delivered online. For example, one study from 2023 suggests that online cognitive behavioral therapy (CBT) “yields similar effects” to in-person CBT in many cases.