What does Proverbs 17:22 mean?

Solomon offers sound medical advice in this verse. A person's attitude affects his outlook on life and even his health. If he is joyful, negative circumstances don't knock him off balance and cause him to despair. Over the centuries, medicine has become more and more aware of the influence a person's happiness has on their overall health. The ultimate source of joy is found in a relationship with Christ (Proverbs 10:28; John 15:11). The believer can rejoice in the Lord, as Paul did even when he was a prisoner in Rome. From his imprisonment, he urged the Philippian believers to rejoice in the Lord (Philippians 3:1; 4:4). Instead of looking around at circumstances, a joyful believer looks to the Lord and rejoices in Him.

In contrast, being mentally beaten down leads to the physical symptoms of severe depression. Whoever fails to look to God and His faithful goodness becomes joyless and loses hope. He develops what Solomon calls "a crushed spirit." A crushed spirit produces ill-health, perhaps high blood pressure, ulcers, lack of energy, heart disease, or general malaise. The apostle James advocated for a resilient spirit even in the face of trials. He writes in James 1:2, "Count it all joy, my brothers, when you meet with trials of various kinds."