Is your child’s moodiness a sign of typical teenage angst—or the beginning of a depression that needs professional attention?

Statistics show that teen depression is on the rise. In 2016, around 13% of U.S. teenagers ages 12-17 had at least one major depressive episode in the past year, compared to almost 8% in 2006, according to the Substance Abuse and Mental Health Services Administration, which collects this information. Rates for teenagers ages 18 and 19, which are tracked separately, grew as well: More than 11% had a...