Many people have heard of and probably experienced déjà vu — the strange feeling you have already seen or experienced something as you are seeing or experiencing it. But very few people know about the opposite of déjà vu, known as jamais vu, when a familiar experience feels new. Why does it happen, and what takes place in the brain?

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Why do familiar experiences sometimes feel strangely new? Image credit: Jens Kalaene/picture alliance via Getty Images.

Jamais vu, which in French means “never seen,” is a phenomenon many people may not have heard of. However, almost everyone has experienced it in their lives.

Have you ever suddenly looked at a word that you write frequently and questioned whether you spelled it correctly, as if you we seeing it for the first time? That could be jamais vu.

Or have you walked into your childhood home as an adult, and for some reason, the living room — which has not changed — feels completely unfamiliar to you? That is jamais vu.

While jamais vu can be disconcerting, what does it mean for our health? What happens to the brain to cause jamais vu? And does it have any implications for brain health and mental health?

Medical News Today spoke with six medical experts to get the lowdown on this unusual occurrence.

In basic terms, jamais vu is the experience of feeling unfamiliar with something that is very familiar to you.

“We describe jamais vu as the opposite of déjà vu — it is the feeling that something is unreal or unusual, whilst at the same time knowing it is something you are very familiar with,” Dr. Chris Moulin, a researcher in the Laboratoire de Psychologie & NeuroCognition at the Université Grenoble Alpes in France, and lead author of a study on jamais vu, told MNT.

“You get it, for example when a word that is [spelled] correctly looks ‘wrong’,” he explained.

“Jamais vu is a psychological phenomenon that involves a temporary feeling of unfamiliarity with a familiar word, phrase, or even a familiar person or place,” Dr. Dung Trinh, founder of HealthyBrainClinic, added.

“In the case of jamais vu, you encounter something familiar, but it suddenly seems strange or completely new to you, as if you’ve never seen or heard it before,“ he also noted.

What exactly causes jamais vu currently remains a mystery. However, some of the experts MNT spoke with shared their hypotheses on what might happen in the brain to cause jamais vu.

Neuropsychologically, jamais vu is an experience of recall without recognition — a temporary disconnection between our perception and memory, explained Dr. Karen D. Sullivan, a board-certified neuropsychologist and owner of I CARE FOR YOUR BRAIN.

“It is likely that brain pathways that are typically in sync become temporarily disconnected. It has been theorized that we differentiate between the novel and the familiar through a series of circuits in the midbrain and that a disconnection from medial temporal memory structures gives rise to the sensation of jamais vu.”

– Dr. Karen D. Sullivan

In addition to interference with memory processing, Dr. Trinh theorized that jamais vu may be the result of temporal lobe dysfunction due to fatigue, stress, or neurological conditions, as well as imbalances in neurotransmitters, such as dopamine or serotonin.

“Another theory suggests that jamais vu may result from disruptions in attentional mechanisms,” he added. “When you’re not paying full attention to something familiar, your brain may temporarily process it as unfamiliar.”

Dr. David Merrill, a geriatric psychiatrist and director of the Pacific Neuroscience Institute’s Pacific Brain Health Center in Santa Monica, CA, hypothesized that there might be an overlap between jamais vu and dissociative, out-of-body experiences generated through the use of psychedelics like psilocybin, which he said can be quite disorienting if not expected.

“Part of what’s so jarring about this phenomenon is it’s unexpected,” Dr. Merrill emphasized. “To suddenly feel disoriented and not know why, or to not have anticipated that you’re going to have this almost out-of-body experience, could be very frightening because there’s no certainty that it’s temporary, as opposed to — if you take psilocybin, you can know there’s about 6 to 8 hours of the psychedelic experience where the brain activity is changing in a way that’s been studied and reliably can help increase neuroplasticity, and may help people be less depressed or less anxious if it’s used in a way to process thoughts and feelings and experiences.”

Dr. Moulin stated that jamais vu may be a useful model when thinking about delusions and striking forms of psychological stress:

“It is a little window into how strange feelings and evaluations can occur. The feeling that a word is [spelled] wrong even [though] you know it isn’t, is not unlike delusions such as Capgras [syndrome], where you say that someone looks like they should, but they are not who they seem to be. Often the delusion involves a well-known person having been replaced by an identical looking imposter.”

“Jamais vu illustrates a bit how higher-level feelings and processes can become dissociated from perceptual processes like word reading or face recognition,” Dr. Moulin continued.

“In healthy populations it’s just for a fleeting moment. In delusions, it happens in a distressing and convincing manner. And in our experiment [for the study on jamais vu], it happens as a result [of] having ‘over-processed’ a word until it becomes too automatic,” he explained.

Although any person at any time can experience jamais vu, past research shows the phenomenon can occur during the aura stage that happens before a person with epilepsy has a seizure.

“A seizure is an electrical discharge in the brain,” Dr. Jacqueline A French, professor of neurology at NYU Grossman School of Medicine and chief medical and innovation officer for the Epilepsy Foundation, explained to MNT.

“Jamais vu is thought to usually arise when an electrical disturbance starts in the temporal lobe, an area associated with memory — and also the area associated with déjà vu,” she noted.

“During a seizure, the feeling of jamais vu is often associated with fear — you can imagine if you are feeling everything around you is strange and unfamiliar,” added Dr. French. “People with fearful feelings during seizures can be prone to anxiety.”

Previous studies have also found that jamais vu occurs during migraine auras, and may also occur in people with amnesia or certain types of aphasia.

According to Dr. Sullivan, jamais vu in nonpathological, typical settings are brief and can be easily regulated by the individual pausing and returning to the material.

“In instances where the person cannot seem to consciously ‘override’ these experiences, a neuropsychologist would want to do a seizure work-up or consider a psychological reaction like dissociation,” she added.

In addition to a sign of neurological disorders like epilepsy or migraine, Dr. Trinh said jamais vu may also hint at other underlying issues.

“Jamais vu can occur during periods of stress, fatigue, or sleep deprivation,” he explained. “It might be a temporary and benign phenomenon in such cases. However, chronic stress and sleep disturbances can have detrimental effects on mental health, so addressing these issues is important.”

“[I]n certain situations, jamais vu may [also] be linked to psychological factors, including anxiety or dissociative disorders,” Dr. Trinh added. “Understanding and addressing the underlying psychological factors is essential for mental health.”

If someone experiences jamais vu repeatedly, Dr. Merrill said it would make sense for them to ask their primary care doctor about seeing a neurologist and having a medical evaluation related to their brain activity.

“[It] shouldn’t be something that we’re experiencing often day to day,” he continued. “If it does come up repeatedly, it might signal that there’s something changing in the brain. There are really good treatments for seizure disorders and epilepsy, so if you’re worried about it, you should get checked out.”

With current research on jamais vu so limited, all experts agree this is an area that merits more studies to fully understand what causes it and what it might mean for a person’s overall health.

Because jamais vu is so much rarer than its sister paramnesia [memory abnormality], déjà vu, research is scarce, with only a few published reports,” Dr. Sullivan said. “It would be helpful to have much larger sample sizes to characterize this human experience in a more systematic and insightful way.”

“It would be interesting to know whether jamais vu seizures are associated with anxiety,” Dr. French added.

And Dr. Merrill said he would like to see researchers use imaging to find out what is the underlying mechanism behind jamais vu.

“You can do functional brain imaging using MRIs, you could do quantitative electroencephalography (EEG),” he detailed. “I’d like to see some brain imaging to actually confirm what are the changes because I’m sure it has a biological basis.”

“It’s not just the psychology of ‘am I spelling that right?’,” Dr. Merrill continued. “It’s not just angst about spelling mistakes. I think it’s very much inducing the same way that you might have for psychedelics, holotropic breathwork, or for any sort of meditative chanting of a mantra. It’s essentially inducing a meditative state. It would be interesting to see if the brain activities are similar.”

“And in contrast, is there a way to induce déjà vu […] [to] compare and contrast that in terms of the brain imaging mechanisms,” he added. “There’s certainly more work to come in this area — it would be great to see it carried out.”