Déjà vu

Déjà Vu (or Deja Vu) is defined as as any sudden inappropriate impression of familiarity of a present experience with an undefined past.^[1][2][3][4] Its two critical components are an intense feeling of familiarity, and a certainty that the current moment is novel.^[5] This term is a common phrase from the French language which translates literally into “already seen”. It is a well-documented phenomenon that can commonly occur throughout both sober living and under the influence of hallucinogens.

Within the context of psychoactive substance usage, many compounds are commonly capable of inducing spontaneous and often prolonged states of mild to intense sensations of déjà vu. This can provide one with an overwhelming sense that they have “been here before”. The sensation is also often accompanied by a feeling of familiarity with the current location or setting, the current physical actions being performed, the situation as a whole, or the effects of the substance itself.

This effect is often triggered despite the fact that during the experience of it, the person can be rationally aware that the circumstances of the “previous” experience (when, where, and how the earlier experience occurred) are uncertain or believed to be impossible.

Déjà vu is often accompanied by other coinciding effects such as olfactory hallucinations and derealization.^[6] It is most commonly induced under the influence of moderate dosages of hallucinogenic compounds,^[7] such as psychedelics,^[8] cannabinoids,^[9] and dissociatives.