Déjà vu is a feeling of having experienced something before, even though it is happening for the first time. It is a common experience, with around 60% to 70% of people experiencing it at some point in their lives. The exact cause of déjà vu is not fully understood, but there are several theories:

• Memory recognition: One theory suggests that déjà vu occurs when parts of the brain that recognize familiar situations get activated inappropriately, causing another region of the brain to check this feeling of familiarity against past experiences.

• Miscommunication between brain regions: Another theory suggests that déjà vu is caused by dysfunctional connections between the parts of the brain that play a role in memory recollection and familiarity. This causes a disruption of recognition memory systems, which gives a false sense of familiarity.

• Split perception: The theory of split perception suggests that déjà vu happens when you see something two different times. The first time you see something, you might take it in out of the corner of your eye or while distracted. Later, when you see it again, your brain falsely perceives what’s happening in the present as a memory, or something that already happened.

• Electrical malfunction: Another theory suggests that déjà vu happens when the brain experiences a brief electrical malfunction, similar to a glitch.

Déjà vu is not inherently unhealthy and is most likely to happen to people who are 15 to 25 years old, with the likelihood of experiencing it decreasing progressively as you age. It can also happen more frequently during evenings and on weekends than during weekdays. Stress and exhaustion can contribute to déjà vu, but it can also be a sign of seizure disorders, migraines, and disorders affecting memory. If feelings of déjà vu are accompanied by other symptoms such as confusion, headaches, loss of awareness, weakness, seizures, or shaking, it may be a sign of a health issue.