In the play, hamlet, act 1, scene v, line 179-180: "as i perchance heareafter shall think meet/to put an antic disposition on-"
is hamlet mad?

Im not sure i would think no but when i was doing reasearch i found this:
 Some actors have skirted the issue of the 'antic disposition' whilst others have played it as neurosis or depression. In some productions Hamlet's madness is comic, in others quirky. Hamlets have been hip, bland, tortured, over-sensitive and pyjama-clad. In rehearsal for this production there was a discussion about the purpose Hamlet's madness serves. It isn't that he simply goes crazy: he utilizes his sharp wit to get at Claudius and the new king's chief spy, Polonius. Hamlet's madness is very different from the madness Ophelia suffers. Heartbreakingly, Ophelia really does go mad - she loses her wits. Hamlet on the other hand remains lucid but uses a disguise of madness (the 'antic disposition') to get him to where he needs to be. Polonius tells Claudius straight away that Hamlet is mad because, the company decided, if Hamlet is known to be mad, he is no longer a threat to the king and cannot accede the throne. That is why Claudius latches on to the idea of Hamlet's madness and why Gertrude is so reticent to believe her son has lost his wits.  The consciousness of his guilt made him alert and, like a criminal ever fearing detection, he suspected the concealment of some evil design under Hamlet's mimic madness. If today we find eminent physicians standing with Polonius and the Queen in the belief of Hamlet's real madness, we see on the opposite side others with the astute king and an overwhelming majority of Shakespeare's readers. That many physicians should deem the Prince's madness a reality is nothing surprising. Well known are the celebrated legal cases in which medical specialists of the highest rank were divided in judgment on the sanity or insanity of the man on trial.

so im not sure if i was you id probably pick YES because from what ive read it seems to me like he was mad alot