From Plato’s Charmide

Zamolxis, …says further,

“That as you ought not to attempt to cure the eyes without the head, or the head without the body, so neither ought you to attempt to cure the body without the soul; and this,” he said, “is the reason why the cure of many diseases is unknown to the physicians of Hellas, because they are ignorant of the whole, which ought to be studied also; for the part can never be well unless the whole is well.”

For all good and evil, whether in the body or in human nature, originates, as he declared, in the soul, and overflows from thence, as if from the head into
the eyes. And therefore if the head and body are to be well, you must begin
by curing the soul; that is the first thing.

“Let no one,” he said, “persuade you to cure the head, until he has first
given you his soul to be cured…”

Plato's Head

Plato’s Head