Imagine if, for the rest of your life, you never experienced anything new: no surprises, no firsts, nothing you hadn’t done or seen or heard about before. Kind of like Groundhog Day, except that time passes normally — it’s not the days that repeat, but the events that fill them.
Such was the case of a 19th-century Frenchman named Louis, who was plagued by an unshakeable sense of familiarity even in new situations. His condition was originally documented by the French psychiatrist Francois-Léon Arnaud, whose 1896 case report was among the first pieces of scientific literature to use the term déjà vu (literally, French for “already seen”). More than a century later, a paper in the journal Cortex, recently highlighted by the the Discover blog Neuroskeptic, has revisited pathological déjà vu, taking a new look at Louis in light of what researchers now know about memory.
The patient: Louis, a former soldier who had previously suffered bouts of amnesia, checked himself into a mental hospital in 1894 with “manifest neurasthenia” (a 19th-century term for something like burnout), recurring headaches, insomnia, and irritability. But the strangest of his symptoms, Arnaud wrote, was a new twist on a feeling he’d had throughout his life: “Louis said that he had experienced several times in his childhood the impression of déjà vu which is now incessantly with him; he used to think that he was mistaken whereas now he is certain that his impression is real.”
The problem: In Louis’s mind, everything that happened had happened already, a perception that made him increasingly agitated. Newspaper articles were just rehashes of past events; even his brother’s wedding, he believed, was a staged reenactment of a celebration that had already taken place, replicated down to the last detail. Shortly before the start of Louis’s hospital stay, his delusions had worsened, sometimes sparking violent reactions, and he became convinced his family was conspiring against him — at one point, he went to, and then immediately left, a different treatment center, insisting over his parents’ objections that he’d already been there before. Once he arrived at his new institution, Arnaud wrote, the same pattern took hold:
He recognised successively everything he saw: the yard, the lounge with the sofa and curtains, the gardens in all their detail, the people who welcomed him made the same gestures, said the same things, and he gave the same answers. He said that it was last year at a similar time that he came to the Institute and like last year, he wanted to leave.
When I first met him, here is exactly what happened: He responded to my greeting in an appropriate manner for someone who is with someone he does not know. Several words were exchanged and his physiognomy changed and he said to me with a smile: “I recognise you now, doctor! It was you who greeted me last year at exactly the same time in the same lounge. You asked me the same questions and I gave the same answers. Everything is very clear to me. You act surprised very well, but you can stop now.” Despite my energetic disagreement, Louis maintained his conviction.
The diagnosis: Arnaud hypothesized that Louis’ “illusion déjà vu,” as he called it, was simply an instance of normal déjà vu gone haywire. Mild cases with distinct end points, he wrote, could happen in otherwise psychologically healthy people, but the condition became a pathology if the patients, like Louis, were unable to snap themselves out of it.
But with what researchers now know about déjà vu, the Cortex authors argue, the label no longer makes sense for this particular case. In the modern understanding, a person is fully aware of the cognitive weirdness that’s taking place — they may feel a sense of familiarity, but they also know that it’s unwarranted for the situation at hand. But when someone is utterly, completely convinced that they’re correct, something else is going on. (As examples, the authors described patients of their own with symptoms similar to Louis, who have “refus[ed] to sign the Christmas cards to be sent because they have already done them, or when a letter arrives announcing the funeral of a friend, they claim the friend had already died.”)
Instead, they proposed a few alternative diagnoses for Louis: Perhaps he was suffering from “recollective confabulation,” a memory disorder in which people interpret new information as familiar and unwittingly fabricate details to support their claims. Or perhaps he had a form of “reduplicative paramnesia,” the belief that places, situations, and even entire people have been copied from their originals, two identical sets of circumstances somehow existing at once.
So many years after the fact, though, it was hard to name any one condition with any certainty: “We will probably never be very sure of the neurological basis of Louis’s delusion,” they wrote. But regardless, his case is one more reminder of the many, ways that human memory — unreliable, malleable thing that it is — can fool us into misunderstanding our own lives.