Another result from Hamlet's peculiar actions, is that in his own mind he begins to believe that he is mad. It is unfortunate that Hamlet's plan did not succeed; not only did it lead to his own downfall but he had to witness the downfall of all of the people he loved.
Although Hamlet and Ophelia are the only characters thought to be so afflicted, the reactions of other characters to this madness mirrors their own preoccupations.
Madness typically occurs in the minds of individuals that have experienced an event or series of events that their mind simply cannot cope with and, thus, to avoid their harsh reality, they fall into a state of madness.
Hamlet certainly displays a high degree of mania and instability throughout much of the play, but his "madness" is perhaps too purposeful and pointed for us to conclude that he actually loses his mind.
˜⇇ The Straight Mind: And Other Essays [Monique Wittig]
This is when the idea of the creature being a doppelganger comes into the picture; when Victor and others neglect this “child”, the creature learns that while possessing such looks, no one will accept him....
The Straight Mind and Other Essays - Revolvy
This paper argues that the contrapuntal character in the play, namely Ophelia, acts as a balancing argument to the other character's madness or sanity. Shakespeare creates a contrasting relationship between the breakdown of Ophelia and the "north-north-west" brand of insanity used by Hamlet in that while Hamlet's character offers more evidence for a contriving manipulation, Ophelia's breakdown is quick, but more conclusive in its precision....
The Straight Mind And Other Essays - College Essay …
The start of Ophelia’s madness is contributed through examination of her relationships, and soon adding up the the loss of her loved ones, her father Polonius, her brother, Laertes, and her lover Hamlet.