Perhaps all of us have experienced a strange feeling – when you feel like you have already encountered a situation, a scene, or a sensation before, even though you can't recall exactly when it happened. This phenomenon is commonly known as Déjà vu.

Déjà vu is a natural psychological phenomenon that occurs when the brain processes new information, causing a sense of familiarity with a specific situation. This phenomenon is not pathological. Déjà vu tends to start and end quickly, usually providing a fleeting feeling. You might feel slightly confused and uneasy, but it passes swiftly.

In some special cases, déjà vu can be a symptom of certain psychological disorders or medical conditions, such as Alzheimer's disease, epilepsy, and various psychiatric disorders. However, in most cases, déjà vu is just a normal and natural psychological phenomenon that does not directly impact health and well-being.