A neurologist explains déjà vu: Why your brain feels you’ve lived a moment before

4 min readNew DelhiJun 20, 2026 05:58 PM IST

Have you ever walked into a room, met someone, or experienced a situation and felt an overwhelming sense that you’ve lived through the exact moment before? That strange sensation, known as déjà vu, has fascinated scientists and philosophers for decades. Recently, neuroscientist Vidita Vaidya shed light on one of the leading scientific explanations behind the phenomenon.

Speaking on Raj Shamani’s podcast, Vaidya described a theory involving “engrams”—the brain’s physical memory traces. She explained that when we experience an event, the brain creates a memory of that moment by activating specific groups of neurons. Later, if we encounter a new situation similar to the original experience, parts of that memory network may reactivate.

According to Vaidya, this partial activation can trick the brain into feeling as though the current situation has happened before, even when it hasn’t.

DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.

Is déjà vu really just a memory glitch?

According to Dr Neha Kapoor, Associate Director and Head-Neurology, Asian Hospital, Faridabad, neuroscience largely supports the idea that déjà vu is linked to memory processing rather than evidence that a person has genuinely experienced the moment before.

“The present state of neuroscience is mostly in support of déjà vu as a memory-processing phenomenon, not proof that a person has actually experienced the moment before,” says Dr Kapoor.

“One leading theory is that the brain misidentifies a new experience as something that has been experienced before,” she explains. “This can happen when aspects of the environment resemble fragments of previous experiences that you do not consciously remember.” Importantly, she stresses that this does not mean the brain is malfunctioning. “Instead, it reflects the remarkable complexity of memory systems that are constantly comparing new information with vast stores of past experiences.”

Why do some people experience déjà vu more often?

Dr Kapoor notes that age appears to play an important role. “Research has shown that déjà vu is more common among adolescents and young adults, particularly between 15 and 30 years of age,” she says. Interestingly, frequent episodes are often reported by healthy individuals who are cognitively active, well-educated, travel often, or regularly find themselves in unfamiliar environments.

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“Frequent déjà vu in otherwise healthy people does not necessarily indicate a problem,” says Dr Kapoor. “It may simply reflect a brain that is actively processing and comparing new experiences with stored memories.”

When can déjà vu signal a neurological problem?

“Occasional déjà vu is considered a normal experience that occurs in most healthy adults at some point in their lives,” says Dr Kapoor. However, unusually frequent, prolonged, or intense episodes may sometimes be associated with neurological conditions, particularly those involving the temporal lobe.

One of the strongest known links is with temporal lobe epilepsy. In some patients, a powerful feeling of déjà vu can occur as an aura—a warning sign before a seizure. “In these cases, the sensation may be accompanied by changes in awareness, unusual smells or tastes, confusion, involuntary movements, or brief periods of unconsciousness,” explains Dr Kapoor.

Warning signs that should prompt a neurological evaluation

Dr Kapoor advises seeking medical attention if déjà vu episodes become unusually frequent or are accompanied by other neurological symptoms. You should consult a neurologist if you experience:

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Increased frequency of spontaneous déjà vu episodes

Episodes associated with blackouts, confusion, or memory loss

Unusual smells, tastes, or visual disturbances during episodes

A family history of seizures or epilepsy

New neurological symptoms such as headaches, weakness, or changes in mental status

DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.