Synopsis As Introduced Amends the State Finance Act. Creates the Fund Mental Health and Substance Use Prevention Fund as a special fund in the State treasury. Provides that the Department of Human Services must make grants, from appropriations made from the Fund, to units of local government and Illinois public universities for the purposes of providing mental health and substance abuse prevention to people who are incarcerated and providing mental health and substance abuse prevention for those encountering the criminal justice system with a primary focus to people who are incarcerated in the county jail or recently discharged. Provides that, as soon as practical after the effective date of the amendatory Act, the State Comptroller shall direct and the State Treasurer shall transfer the sum of $100,000,000 from the General Revenue Fund to the Fund Mental Health and Substance Use Prevention Fund. Provides that notwithstanding any other provision of law, moneys in the Fund Mental Health and Substance Use Prevention Fund may not be appropriated, assigned, or transferred to another State fund.