NORWALK, WIS. — Not long ago, a local farmer here plunged into a depression so intense that he could barely muster the strength to leave his bed. The 40-something father of eight went dark for weeks, despite the enormous amount of daily work needed to keep his family farm going. “If you are running a small farm, you still have to get up and milk the cows. You got to go put the crops in. There are demands that nature doesn’t let you forget,” explained Jerry Menn, a farmer and doctor who was familiar with his friend’s crisis. “His massive...