How, if at all, is Hamlet figuratively diseased, as distinct from literally diseased?William Shakespeare's Hamlet.
Shakespeare's Hamlet would well fit into the twenty-first century. For, his is a case of "clinical depression." Hamlet sees his world realistically and it is--to paraphrase Wordsworth--too much with him. Recognizing the lustful urges of his mother that are inappropriate for her age, and somewhat Oediphal/complex in his anger with her, Hamlet reviles her and becomes rather misogynistic in the process as evidenced by his cruel treatment of his beloved Ophelia. Not adept at the "situational ethics" suggested by his father, Hamlet suffers from inner conflicts as the dutiful son, who much like the "team player" at work, is asked to compromise his ethics and do what is expedient.
Then, as he continues his self-debates about suicide and avenging his father's death, Hamlet observes the senseless sacrifice of soldiers to their cause in his conversation with Fortinbras. After this, he experiences a delusional epiphany and decides to be the Prince of Denmark and rid his country of that which is "rotten." He dies and leaves in his wake many other bodies--not unlike the stereo-typical "disgruntled postal worker" or campus killer.
Hamlet is most certainly affected mentally by grief after the loss of his father. He is also upset by the hasty marriage of his mother, Gertrude, to his father's brother, Claudius. Hamlet has been driven to commit murder by his pent-up emotions and yet seems to revel in his crime. He is possibly experiencing some sort of dissociation as he calmly drags his stepfather’s body from the stage. Hamlet is also clearly suffering from delusions when he sees the ghost of his father.
Hamlet's dis-ease is caused by his unfortunate experiences, but also from his melancholy nature. This could be the figurative condition to which you refer.
I do not see that Hamlet is physically diseased – it is his mental state of extreme lucidity and then strange ramblings which indicates his condition could be aligned to manic depression. We can see mental illness as a physical disease, but its physical manifestation is merely in his actions.