Will being OCD makes so much sense, it's crazy that we never considered it as much as all other mental disorders, thank you for pointing that possibility out!!

The sad truth is that it’s not considered because a lot of thoughts have been normalized, like feeling paranoid that you are bad and will be punished, that god is judging and watching you etc. Religious people think this is not only normal but expected. This is just a pathology. It’s an illness that needs treatment and unfortunately society has normalized this. So we don’t see OCD as more than the person obsessed with cleaning, and that whole stereotype.

Will is not only OCD with morality, but his alcohol addiction is also a part of an OCD behavior. Addiction functions, in certain parts of the cycle, as obsession. Unfortunately that wasn’t as explored on the show, but I think it was clear from the subtext (also I think in the book it’s a lot more obvious).