Dr. Chris van Tulleken wants to understand why British children are taking three times more medication than they were 40 years ago. He looks into one of the biggest health crises facing young people - depression. The number of children in Britain being treated with drugs for depression almost doubled from 2005 to 2015. Chris wants to know why so many children are being given these meds and whether they actually work. He discovers that most antidepressants are not effective in children, while there is also a very real risk of them increasing suicidal thoughts. He meets 15-year-old Jess, who is so anxious she hardly leaves her bedroom. Over several months, and with Chris's help, she takes up wilderness therapy. Chris also looks into prescriptions for milk formula to treat babies with cow's milk allergy. These rose by almost 500 per cent in the ten years to 2016, and prescriptions are now costing the NHS over £64 million a year.