JUDY WOODRUFF:

Now let's turn to our series on the opioid crisis, its enormous toll in American life, and efforts to get a handle on it.

We have spent the past couple of days showing some of the devastation it has wreaked, as more and more people have become hooked.

Tonight, as part of our weekly Leading Edge science segment, Miles O'Brien explores the mechanics of pain, and some possible alternatives for coping with it.

It's part of our ongoing focus, America Addicted.