6 Health of Mind and Body
Of all the things that I have lost, I miss my mind
the most.— Mark Twain“What do you most desire in life?” Many people say physical
and mental health. Physical pain is one of the worst of all
human experiences— bodily torture being an extreme case.
And mental pain is as bad as most physical pain, and very
similar— it is experienced in the same brain areas as the af-
fective components of physical pain.^1 Indeed mental illness
is the most common cause of suicide.^2
So both mental illness and physical illness are major
causes of human wretchedness. But many existing studies
of life- satisfaction ignore mental illness. Implicitly they as-
sume that misery and mental illness are the same thing. As
we argued in Chapter 1, this is quite wrong. Many things
can cause low life- satisfaction, some of them directly and
others indirectly by causing mental illness. But there are
also sources of mental illness that are uncorrelated with
any of the obvious external causes like poverty, unemploy-
ment, separation, or bereavement. We overlook a key part
of human experience if we overlook mental illness of that
type.^3 Multiple regression enables us to study the effects of
that type of mental illness, by holding constant the obvious
external causes.