; serious mental illness (i) Adult with a serious mental illness The term adult with a serious mental illness has the meaning given that term by the Secretary pursuant to section 1912(c) of the Public Health Service Act. (ii) Serious mental illness The term serious mental illness means a diagnosable mental, behavioral or emotional disorder that meets the criteria for qualifying an individual as an adult with a serious mental illness. (B) Assertive community treatment The term assertive community treatment means services for the treatment of mental illness that are provided through an evidence-based practice that— (i) improves outcomes for individuals with severe mental illness who are at high risk of homelessness, psychiatric crisis, or hospitalization, or are involved in the criminal justice system; (ii) is comprised of a multidisciplinary staff, including peer specialists, who work as a team to provide the individualized psychiatric treatment, rehabilitation, and support services clients need for the maximum reduction of physical or mental disability and restoration to their best possible functional level; (iii) ensures that there is 1 direct care staff person for every 10 clients; and (iv) provides services 24 hours a day, 7 days a week, for as long as needed and wherever they are needed. (C) Eligible individual The term eligible individual means an individual— (i) who is eligible for medical assistance under the State plan or under a waiver of such plan; (ii) who is age 21 or older; (iii) whose income does not exceed 150 percent of the poverty line (as defined in section 2110(c)(5)); and (iv) who is an adult with a serious mental illness. (D) Intensive case management The term intensive case management means a type of case management service (as defined in section 440.169 of title 42, Code of Federal Regulations)— (i) that is reliable, systematic, flexible, and coordinated, designed to answer the unique combination of health and social care needs of individuals with serious mental illness