"Brain scans appeared normal, suggesting the cause was psychological rather than neurological."

The proper functioning of the brain is contingent on far more than its macroscopic structure.

Calling this disorder "psychological" will just lead to its sufferers dismissed as crazy. Anxiety causes deja-vu? Obviously if that was the case it would be much more prevalent. Anxiety is normal, deja-vu isn't.

Society still has a long way to go when it comes to blaming people for psychology but not physiology. In truth there is no difference; everything the brain does is physical at its roots. Even if you suppose a particular psychological phenomenon is purely emergent from self-reinforcing electrical patterns (a "feedback loop") in an otherwise unmodified brain, those patterns still exist in a physical form. Whether a psychological problem is caused by bad signals or bad substrate should be irrelevant to the notions of blame or stigma.

I was surprised that only two thirds of people ever experience deva vu. I experience it a couple of times a week and usually say something when I do if someone is around. Nobody ever mentioned that they didn't know what it felt like. Perhaps it's time for a poll.

I once received a minor concussion in an automobile accident. I was hospitalized overnight for observation and then released. A couple days or so later, I opened my mailbox and there was a pamphlet from the hospital telling me what to expect as a victim of a minor brain injury. One of the things it said was that I might experience feelings of déjà vu.

For some reason, the hospital actually mailed me two copies of that pamphlet, a day apart, and so when I opened the mailbox the next day, I did indeed get a feeling of déjà vu!

Or has he been traveling in different time lines?