"A cheerful heart makes good medicine" (17:22). Is the verse saying a cheerful attitude will heal you?

Here is what it says: "A cheerful heart makes good medicine, but a crushed spirit dries up the bones" (17:22) (tap medicine). The Hebrew word for medicine, gehah, comes nowhere else in the Hebrew Bible, and Brown-Driver-Briggs gives it as "healing, cure". The saying sets two hearts side by side and says what each does. It doesn't say how, it doesn't promise that every illness will go, and it doesn't blame anyone whose spirit is crushed. Proverbs speaks of a crushed spirit three times, in the same Hebrew words (15:13, 17:22, 18:14), and one of them asks a question: "A man’s spirit will sustain him in sickness, but a crushed spirit, who can bear?" (Proverbs 18:14). The notes on Proverbs 15 set 17:22 beside another, "A glad heart makes a cheerful face" (Proverbs 15:13), which opens with the same three Hebrew words. These are sayings, and these notes don't turn 17:22 into advice about anyone's health or treatment.