I would hardly call it a disorder, but it’s enough to give some thought to. We’ve all heard of PTSD (Post Traumatic Stress Disorder), which I’ve never been through, but I have experienced depression before. And that depression was similar to, yet different than a post travel low. A post travel low is interesting, you get back and you’ve seen things that you know your friends haven’t, and therefore they can’t understand. You feel like you’ve changed, and there is no one to relate to, yet you feel you’re stronger and better than before for knowing. But yet ignorance is bliss, and therefore knowledge can bring sadness. I think this could be very similar, yet not nearly as intense as PTSD. Just a thought.