From my own experience, sin does indeed lead to death. A sort of death while your body is still alive yet little life or spirit remains. Depression, guilt, trauma, etc. Example for convenience would be lust. Lust is the objectification of the universe. Seeing others as simply a vehicle to attain pleasure. This leads to a denial of God and soul within others and ourselves. The greatest sin is blasphemy not because it is a sin to question God but because it is one to deny God's being and your own soul dies with that.