The Atlantic | W Keo/Magnum
You have to admit, it seemed like a great way to help anxious and depressed teens. Researchers in Australia assigned more than 1,000 young teenagers to one of two classes: either a typical middle-school health class or one that taught a version of a mental-health treatment called dialectical behavior therapy, or DBT. After eight weeks, the researchers planned to measure whether the DBT teens’ mental health had improved.