Chronic pain sufferers who learn to dwell less on their ailments may sleep better and experience less day-to-day pain, according to results of research.

Why are the researchers assuming that the positive thinking caused the better sleep and not vice-versa?

Anyone who's ever been around an overtired toddler knows that lack of sleep makes a person cranky and way oversensitive - prone to being bothered by things that normally wouldn't be such a big deal.  So what do you think would happen if someone had chronic pain and chronic insomnia?  Might they perhaps be exceptionally cranky about the pain they're feeling?

The next step in the study should be to take the positive-thinking people, keep them up for a night or two, and see what happens to their attitude; then put the negative thinkers on a bedtime regimen of a hot bath, some mindfulness mediation, and a sleeping pill and see if that does anything.  

In the meantime, I'm going to go ahead and keep believing that insufficient sleep leads to negative thoughts - not the other way around - because it demonstrably works that way for me and everyone else I know.