Remember back in 1997, the Pokemon seizure episode? Hundreds of children reported symptoms, including seizures, after watching a specific episode of the Pokemon cartoon that includes a sequence of flashing alternating red and blue lights. The press reported the episode at face value, attributing the reaction to a known phenomenon of photosensitive epilepsy. However, later reviews found that the majority of cases were not seizures, and in fact occurred during later viewings of the episode, after the story was widely reported. In one survey, for example, about 15% of the children who reported symptoms reported having actual seizures.
The episode is a great example of a mass hysteria – a story spreading widely in the public that triggers some form of psychological reaction. This could involve a report of a UFO sighting leading to many further reported sightings, or the belief that something toxic is making people in a building sick leading to many people reporting symptoms, even if ultimately there is no underlying cause.
But we do need to keep in mind that, as with the Pokemon case, the original trigger of the mass hysteria was a real neurological reaction in some children. Photosensitive epilepsy is real. It is likely that the intensity and duration of the flashing lights was enough to trigger seizures in some susceptible children. Careful analysis also found that there were some specific conditions that contributed to the actual seizures – the frequency and duration of the flashing lights, viewing the program in a dark room and being closer to the screen.
As a neurologist this is a lesson we have to keep in the forefront of our clinical decision making. We typically use the term “psychogenic overlay” to describe apparently physical symptoms that may have a psychological origin. The “overlay” part is important, because most of the time the psychogenic symptoms are in addition to underlying neurological symptoms. We may also use the term “embellishment”, again to suggest that the psychological component is exacerbating a neurological phenomenon.
Even if we convincingly demonstrate that part of the patient’s symptoms are non-neurological and likely psychogenic, we need to avoid the temptation to conclude that the entire presentation is psychogenic. Most of the time, it isn’t. Very much like the Pokemon incident, something neurological happened which then triggered the psychogenic component. We have to make sure we don’t miss the neurological part because we are distracted by the psychogenic part.
What type of phenomena make up the psychogenic part? That is also an interesting and complex question, about which we should not make lazy assumptions. Sometimes psychological stress and anxiety do manifest as physical symptoms. This is not surprising, given that the brain is physical and part of the body, connected both neurologically and chemically to the rest of the body. Sometimes the connection is straightforward and easy to determine – anxiety leads to hyperventilation which leads to decreased blood CO2 levels which then causes tingling sensations and light-headedness. Sudden stress can also lead to a vasovagal response and fainting.
Other times the connection is a bit more complex. Sometimes sensory symptoms alter the complex sensory feedback mechanisms that are part of our voluntary muscle control. This can make it difficult for a patient to fully activate their muscles, or at least make it feel strange to them. On exam this can lead to decreased effort when testing muscle strength, and make is seem like psychogenic weakness. We can eventually get full strength from the patient, but it takes effort and maneuvering.
Sometimes the connection is still mysterious. Over time the language we use for such phenomena has shifted to better reflect the true state of our knowledge. It is best to avoid terminology that includes assumptions which have not been demonstrated, or that biases thinking in certain ways. For example, some people have events that look like seizures, but we do not see electrical activity on their EEGs (brain wave tests) that show seizure activity. These used to be called psychogenic seizures, but the truth is, we don’t always know if they are psychogenic or not, so now we simply call them non-epileptic seizures.
Also, it needs to be noted that as our technological ability to detect electrographic seizures improved, many cases that were previously thought to be “psychogenic” turned out to be epileptic. This was professionally humbling, and is what lead, in part, to the more cautious approach to other cases.
Some symptoms that are considered to be psychogenic may also result from what is called hypervigilance. These are physical symptoms, but they are likely not part of whatever new problem is going on. These can be chronic symptoms or mild symptoms that are largely unnoticed, until the new symptoms make the patient worried and they start to pay attention to every minor pain or muscle twitch.
Such background symptoms are so common we often refer to them as the “symptoms of life”. Especially as we get older, such symptoms are almost unavoidable. We all get some arthritis, or nerve compression like carpal tunnel syndrome, and may develop a host of symptoms that are difficult to diagnose specifically but extremely common with age.
All of this creates a lot of symptom noise – but again, there is often a signal hiding in that noise. The challenge is often disentangling what is new from what’s old, what is part of the core phenomenon and what is just hypervigilance or stress.
In such situations there are too types of error that clinicians can make. We can overdiagnose problems that are not discrete pathological entities, or we can fail to diagnose genuine new medical conditions. Both types of error carry significant risk, and we have to be careful to avoid both. Missing an acute problem, of course, means that we miss a possible opportunity to treat something, perhaps until it progresses further. Overdiagnosing, however, can lead to unnecessary testing and treatment. It can also create a false confidence in knowing the diagnosis, which can lead to missing other genuine conditions.
In short, the approach to possible psychogenic symptoms needs to be careful, thoughtful, and nuanced. Any simplistic approach is likely to miss important aspects of the what is actually happening, either with an individual patient or a medical phenomenon.