Pediatric psychiatric disorders are increasing every 2 years. Can a fun, well-tested classroom game invented in 1969 reduce these disorders? The answer is “yes.” In this session, participants will learn the following: 1) how the game works; 2) the breadth of longitudinal outcomes; and 3) how to scale up the game. The game is played during regular school instruction. Teachers divide children into 2 to 5 teams per classroom, balancing teams with high-achieving, shy, and disruptive students. The teams work to increase PAX (“peace, productivity, health, and happiness”). If the teacher counts 3 or fewer “spleems” (disruptive behaviors that reduce PAX) per team, the team wins. Rewards vary from written notes praising an individual child to permission for the team to engage in activities not usually allowed during class (eg, tapping a pencil on a desk or throwing paper balls). These activities use peer reinforcement to socialize children. The entire intervention uses positive and playful language. Notes praising a child are called“tootles,” and the rewards for good behavior (pencil tapping, ball throwing) are called “Granny’s wacky prizes.” PAX language directed at teachers and parents is positive and aspirational. PAX materials refer to 4 of the following miracles that happen when children go to school: 1) learning to read; 2) learning to write; 3) learning mathematics; and 4) “acquiring the mental ability to sustain attention, self-regulate or self-manage, and cooperate with others intentionally.” The breadth of longitudinal outcomes was based on multiple RCTs by colleagues at Johns Hopkins and real-world implementations. Population-level implementation of the game shows that it is possible for public or private entities to cost-effectively prevent or treat DSM-5-classified multiple disorders.