Thomas Crooks was acting strangely. Sometimes he danced around his bedroom late into the night. Other times, he talked to himself with his hands waving around. These unusual behaviors intensified last summer, after he graduated with high honors from a community college. He also visited a shooting range, grew out his thin brown hair and searched online for “major depressive disorder” and “depression crisis.” His father noticed the shift — mental health problems ran in the family. On the...