...I was going to post about the scene last night, but didn't, and see if people thought this was a fiegned madness scene or a glimpse of real - if not madness, then being distraught.

He does say to Horatio and Marcellus to pay no heed if, in the future, he were to put on "an antic disposition". This shows the idea was already brewing in his mind.

But, I think an arguement could be made that, after seeing the Ghost and retiring, the ghastliness of it all struck him anew and he became horrorstruck and agitated and went to Ophelia for comfort.