Medicaid Expansion Boosted Specialty Treatment Episodes For Substance Use Disorder In Expansion States, 2010-22.

The Affordable Care Act (ACA) enabled states to expand Medicaid to low-income adults and required expansion programs to cover substance use disorder (SUD) treatment. Extending prior research, we analyzed more recent effects of ACA Medicaid expansions on specialty SUD treatment, using 2010-22 all-payer data on treatment episodes. This period coincides with the worsening national drug overdose epidemic, as well as changes to Medicaid policy through program redesign and under the COVID-19 public health emergency. Using difference-in-differences methods, we found that after expansion, episodes to specialty treatment increased by 28 percent in expansion states compared with nonexpansion states. Financial protection through Medicaid as a source of insurance and payment for services also increased significantly in expansion states compared with nonexpansion states. Medicaid expansion is an important program for increasing access to SUD care for a population with high levels of need.