Adolescence is a crucial period in the development of lifelong mental health, says Center-affiliated faculty member Ronald Kessler. In his keynote at the annual Harvard Catalyst [1] symposium on brain development in the second decade of life, Kessler discussed how the teenage years can begin a “cascade of triggers and problems” that lasts into adulthood. Kessler is the McNeil Family Professor of Health Care Policy at Harvard Medical School.