All behavioral or mood disorders - including depression, OCD, ADHD and addiction - have some neurochemical components, but sufferers can still work to overcome them.

If I can't feel, if I can't move, if I can't think, and I can't care, then what conceivable point is there in living?

Indeed, the best way to think of willpower is not as some shapeless behavioral trait but as a sort of psychic muscle, one that can atrophy or grow stronger depending on how it's used.

We're learning how important it is both to preserve sibling relationships if they work and repair them if they're broken. We're also learning a lot about nonliteral siblings - stepsiblings, half-siblings - and the surprising power they can have.

Except you cannot outrun insanity, anymore than you can outrun your own shadow.

The brain sits snugly inside the skull, but it's not a completely flush fit - there is still a layer of fluid between bone and soft tissue that serves as a natural shock absorber. Some shocks, however, can't be absorbed, and when the head gets clobbered too hard, the brain can twist or torque or rattle around inside its skeletal casing.