In lines 293-310 in Act II, scene II of "Hamlet", what reason does Hamlet give to his friends for his current condition?

Hamlet basically says that he has lost all enjoyment of things. We know this as a classic sign of depression. But Shakespeare puts it much more eloquently when Hamlet says,

"I have of late—but wherefore I know not—

lost all my mirth, forgone all custom of exercises; and indeed,

it goes so heavily with my disposition that this goodly frame,

the earth, seems to me a sterile promontory. . ."

He continues:

"What a piece of work is a man! how

noble in reason! how infinite in faculty! in form and moving

how express and admirable! in action how like an angel! in(310)

apprehension how like a god! the beauty of the world, the

paragon of animals! And yet to me what is this quintessence

of dust?"

In other words, in spite of the greatness of man and the things he can do, nothing can please him anymore. He has lost all sense of pleasure.