Excessive use of screens, social media, and video games by adolescents has caused an alarming increase in suicidal behavior. The Adolescent Brain Cognitive Development (ABCD) study follows 11,000 subjects since age 10 using MRI to study changes in the brain caused by addiction. Guest: J. John Mann, M.D., Professor of Translational Neuroscience in Psychiatry and Radiology, Columbia University.