Is it possible Zack Snyder and co. are borrowing another page out of Christopher Nolan's book?
My theory is that Batman vs Superman, Suicide Squad, and the future DCCU are molding their incarnation of the Joker after Nolan's character Leonard Shelby from Memento.
Recently pictures have surfaced that show ACE Chemicals, which is the exact location in which the Jokers true identity and crazy persona was born. In the comics, Batman causes the Joker to fall into a chemical vat forcing his skin to turn bleached, his hair to be dyed, and for his brains to be scrambled.
Now my theory is that the chemical vat messed with the Joker's brain so much that it not only caused him to become psychotic, but also keeps him from retaining memories, and storing new ones. He gets the tattoos to remind him of his past and to constantly remind him of his greatest enemy, the man who created him...Batman
Let me know in the comments if you think this would be a cool spin on the Joker's mythology, or if you have your own theory or hope for Leto's take on the clown prince of crime!