You walk into a room, and you suddenly feel like you’ve been there before — even though you know you haven’t. The feeling is overwhelming, then it disappears just as quickly as it came on.
The eerie feeling that you’ve been here and done this before is called déjà vu. It’s French for “already seen,” and it can be a very strange and even unsettling experience. Logically, you know you haven’t experienced this moment before, but your brain is telling you otherwise.
Déjà vu is a common experience — about two-thirds of people have had it. But it’s still widely misunderstood. The reason simply is it’s hard to study in a laboratory, so our understanding is limited. There are a few theories, though, about what might lead to this “glitch” in the brain.
Here’s what you should know about déjà vu, what might be causing it, and when to see your physician.
Memory, Stress, Fatigue … Oh My!
A healthy brain can experience déjà vu. This doesn’t necessarily mean you should raise the alarms. The sensation is more likely to happen to people who travel often and have college or advanced degrees. And it can peak in young adulthood, but gradually go away with age. The common factor here? Being busy, tired, and a little bit stressed out.
People who are exhausted or stressed tend to experience déjà vu more. This is probably because fatigue and stress are connected with what likely causes most cases of déjà vu: memory.
A Little Neuroscience on Memory
“Memory is stored in a part of your brain called the temporal lobe. Long-term memories, events, and facts are all pushed right to that area of the brain. Specific parts of the temporal lobe also play a role in recognizing something as familiar,” explains Dr. Roderick C. Spears, a physician with Penn Neurology Valley Forge.
And while it’s not completely proven that déjà vu is connected to the temporal lobe — again due to lack of data from studies — there have been some clues that lead scientists to make this connection.
People who have suffered from temporal lobe epilepsy — a condition where the nerve cell activity is disturbed, causing a seizure — have reported experiencing déjà vu right before a seizure. The common factor is the temporal lobe, forming the connection between déjà vu and memory.
What does this have to do with people who are tired and stressed? Both of these can cloud short and long-term memory. If your memory is impacted, this happens in the temporal lobe, which might lead to a feeling of déjà vu.
Cause for Concern: When Deja Vu Is Something More Serious
Though much rarer, déjà vu is sometimes a sign of a seizure, specifically an epileptic seizure. “About 60 percent of people with epilepsy have something called a focal seizure, which is in just one part of the brain. This can be in the same part of the brain where memory is stored: the temporal lobe,” says Dr. Spears.
Focal seizures can be hard to recognize as seizures because they are short and you remain conscious throughout. A person having one may look like they are having a staring spell or daydreaming.
Some people who have focal seizures may experience intense feelings of déjà vu. This is often accompanied by:
- Motor feelings, which impact your ability to control your muscles, like twitching or the inability to move certain muscles
- Sensory feelings, involving taste, touch, smell, vision, and hearing, like tasting or hearing something that’s not real
- Sudden and unexplainable feelings of joy, anger, sadness, or nausea
- Strange, repetitive behaviors, such as blinking, twitching, or moving your mouth involuntarily
- An unusual sensation that a seizure is about to occur, called an aura
Dr. Spears explains that “these focal seizures can be hard to diagnose and are sometimes confused with other disorders, like narcolepsy, fainting, and mental illness. In order to diagnose it as epilepsy, it may require testing and careful monitoring of your symptoms.”
If you suspect your déjà vu might be a sign of epilepsy, you should see your doctor to get testing, which might include blood tests or an electroencephalogram (EEG).
The Bottom Line About Deja Vu
Many people have experienced or will experience the feeling of having been somewhere or experienced a situation before. In many cases, it’s fleeting and goes away quickly — and that’s that. But it can be a sign of something more serious — such as epilepsy — if you have other symptoms that accompany déjà vu.
More often, though, it just means you might need to get a little more sleep or participate in an activity that can help lower your stress levels.
If you are concerned about your experiences with déjà vu, request an appointment to meet with a Penn Medicine primary care provider to address any underlying causes.