 A new study finds evidence-based talk therapy that's accessed online through a mental health app is effective at reducing symptoms of bulimia nervosa, which is a kind of eating disorder. The study was published in the medical journal JAMA Network Open. NPR's Ritu Chatterjee has more. Bulimia nervosa causes people to alternately binge eat and purge and is associated with poorer physical and mental health. But treatment based on sound scientific evidence can be tough to get.