Ever hear of a weighted blanket to cure insomnia!!?? I made one for my husband out of Bernat Mega Bulky and it really worked! This yarn is heavy and thick, yet super soft, and worked perfectly! It put him to sleep and may even reduce his restless leg syndrome! No need to add anything else to the weight from my experience.
weighted blanket tutorial with free patternalso see pdf pattern here: http://www.fraser.org/tip_sheets/weighted_blanket.pdf and here: http://thesquishypickles.blogspot.com/2011/04/weighted-blanket-tutorial.html