An analysis of the lives of nearly a thousand people shows that a small group who had poor childhood ‘brain health’ accounts for the lion’s share of social costs when they reach adulthood. Twenty percent of participants accounted for 81 percent of criminal convictions, 77 percent of fatherless childrearing, 78 percent of prescriptions filled, 66 percent of welfare benefits, 57 percent of hospital nights, 54 percent of cigarettes smoked and 36 percent of insurance claims.