Have you ever had the sense that you’ve done something or gone through a new situation before? Does it seem like you know what’s going to happen next? That feeling is often described as déjà vu. The saying comes from French, meaning "already seen."
Some people think that déjà vu is a sign of a potential psychic phenomenon. But there may be other causes for your déjà vu experiences.
Who Experiences Déjà Vu?
Around 60% to 70% of people in good health experience some form of déjà vu during their lifetime. A familiar sight or sound can trigger the feeling. You may walk into a room in a building you’ve never visited yet feel like you know it intimately. Most feelings of déjà vu disappear quickly, which can make it hard for you to recall specific details about the experience.
Déjà vu happens most often to people between 15 and 25 years of age. We tend to experience the feeling less as we age. If you travel a lot or regularly remember your dreams, you may be more likely to experience déjà vu than others. Someone who is tired or stressed may be prone to déjà vu feelings, too. Most people have the experience during the evenings or on the weekends.
What Causes Déjà Vu?
Memory gets stored in the temporal lobe of the brain. This part of the brain helps us recognize familiar experiences. While science has yet to prove that everyday déjà vu experiences are a result of memories stored in the temporal area, some researchers believe there is a connection between the two.
One experiment done to test the theory that links déjà vu to memory involved creating virtual reality scenarios based on the world of the video game Sims. Many who participated in the project ended up having various déjà vu experiences tied to scenes resembling similar ones viewed earlier.
Some people often feel that déjà vu may help them predict a future event. But the experiment found that individuals didn’t become more likely to guess the correct path or come up with more accurate answers while playing out the virtual reality scenarios. More research is being done to try to figure out exactly why people have feelings of déjà vu.
What Are the Medical Reasons for Déjà Vu?
Most people experience déjà vu with no adverse health effects. In rare cases, déjà vu can be a sign of a neurological disorder. Individuals with epilepsy often have focal seizures that occur in one area of the brain, sometimes in the temporal lobe where we store memories. These are called temporal lobe seizures.
Seizures involve bursts of uncontrolled electrical activity that cause nerve cells in your brain to misfire. The shortness of focal seizures and the fact that people typically remain awake when they happen make it hard to recognize what's happening. People may mistake a person having a focal seizure as daydreaming or staring off into the distance.
Temporal lobe seizures can produce feelings of déjà vu. Signs that you may be having a temporal lobe seizure versus a regular déjà vu experience include:
- Sudden, unexplained feelings, like joy or anger
- Problems controlling your muscles
- Twitching in your muscles
- Having sensations that involve vision, taste, smell, hearing, and touch
- Feeling as though you are about to have a seizure
Temporal lobe seizures impact your ability to interact with other people. Most of them last anywhere from 30 seconds to minutes. You may lose awareness of your surroundings or realize that you’ve been sitting and staring off into the distance. Others may observe you smacking your lips or constantly chewing and swallowing during the seizure.
Once the temporal lobe seizure ends, you may find yourself feeling confused. It may be difficult for you to speak or remember what happened while having the seizure. A temporal lobe seizure can become a more serious tonic-clonic (or grand mal) seizure that causes convulsions and makes you lose consciousness.
Should You See a Doctor About Déjà Vu?
You should get an evaluation from a doctor if you suspect that temporal seizures or other neurological issues may be causing your feelings of déjà vu. Get help immediately if you:
- Have seizures lasting longer than 5 minutes
- Have trouble gaining control of your breathing after a seizure
- Remain unconscious after having a seizure
- Have a second seizure after the first
- Have other medical issues like diabetes
- Are currently pregnant
- Hurt yourself during a seizure
Seek advice from a doctor if this is your first time having a seizure. Ongoing temporal seizures can shrink the hippocampus, the part of the brain that helps you learn and control your memory. You can also lose brain cells, leading to other memory issues.