Personnaly I would never use such a drug. I conceptualise myself as a tought-based kernel with a bunch of meat around to make it run. This kernel tries hardly to think about itself as 'one thing' (you don't achieve much with schizophrenia), and that relies heavily on this kernel being able to trace a continuous stream of tought back to its birth (at least as far as it can remember). Alter this stream and you loose yourself (the bigger the altering the bigger the loosing).

Two more things: (i) I'm aware that not everybody thinks the same, mainly because fellow humans acts as a constant reminder of who you were before, and (ii) yes, sleeping is disturbing to me, I try not to think about it too much.