Amends the Medical Assistance Article of the Illinois Public Aid Code. Provides that, on and after July 1, 2023, all non-controlled FDA-approved prescription medications for the treatment of a serious mental illness shall be covered under the medical assistance program for persons otherwise eligible for medical assistance who are diagnosed with a mental disorder that meets criteria established in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) and which is the focus of the treatment provided, including, but not limited to, schizophrenia, schizo-affective disorders, bipolar disorders, or major depression. Exempts medications covered under the amendatory Act from any prior authorization or lifetime restriction limit mandate. Provides that, for any covered medication that contains an opioid antagonist, the prescriber shall check the Illinois Prescription Monitoring Program to determine if the patient is being actively prescribed an opioid. Requires a prescriber of any medication covered under the amendatory Act to be a board-certified psychiatrist or a medical professional with prescribing authority that routinely treats patients with a serious mental illness. Effective July 1, 2023.