If “I believe you” are the three most powerful words you can say to someone with an invisible illness, four of the hardest or most painful words to absorb—whether they are said directly or communicated indirectly through insensitive behavior—are “I don’t believe you.” And yet, people who live with depression, anxiety, and other mood disorders...

Answer this question: How often are you kind to yourself and think you’re fine as you are? Choose a number between one and ten. If you rated yourself at a five or less, you fall in line with 46 percent of the 5,000 people recently surveyed by the charity Action for Happiness, in collaboration with...