But you just proved my point, his regression was induced by his mutation and was driving him crazy. Even this regression wasn't really one, it was his natural evolution again induced by his mutation so yes his mutation was responsible for driving him crazy.
Brian Cronin wrote a great article about it :
https://www.cbr.com/abandoned-love-r...ack-to-normal/
Even in Origin, you can see him easily losing his mind because of his feral nature, this feral nature is part of his mutation as much as his healing factor, claws and his acute senses. Of course along the years, things got more complicated and convoluted, same thing with his memory just like you said.
One time it was just the trauma of the Weapon X experiment, then it was implants, then it was Ferro's work then later it was his own healing factor which made him forget his past and finally the last retcon was that Romulus was reponsible for removing his memory even before the Weapon X program.
Wolverine's amazing cooking skills will be even better now !!!!