Prescription Drug Dispensing and Patient Costs after Implementation of a No Behavioral Health Cost-Sharing Law

Importance: On January 1, 2022, New Mexico implemented a No Behavioral Cost-Sharing (NCS) law that eliminated cost-sharing for mental health and substance use disorder (MH/SUD) treatments in plans regulated by the state, potentially reducing a barrier to treatment for MH/SUDs among the commercially insured; however, the outcomes of the law are unknown. Objective: To assess the association of implementation of the NCS with out-of-pocket spending for prescription for drugs primarily used to treat MH/SUDs and monthly volume of dispensed drugs. Design, Settings, and Participants: This retrospective cohort study used a difference-in-differences research design to examine trends in outcomes for New Mexico state employees, a population affected by the NCS, compared with federal employees in New Mexico who were unaffected by NCS. Data were collected on prescription drugs for MH/SUDs dispensed per month between January 2021 and June 2022 for New Mexico patients with a New Mexico state employee health plan and New Mexico patients with a federal employee health plan. Data analysis occurred from December 2022 to January 2024. Exposure: Enrollment in a state employee health plan or federal health plan. Main Outcomes and Measures: The primary outcomes were mean patient out-of-pocket spending per dispensed MH/SUD prescription and the monthly volume of dispensed MH/SUD prescriptions per 1000 employees. A difference-in-differences estimation approach was used. Results: The implementation of the NCS law was associated with a mean (SE) $6.37 ($0.30) reduction (corresponding to an 85.6% decrease) in mean out-of-pocket spending per dispensed MH/SUD medication (95% CI, -$7.00 to -$5.75). The association of implementation of NCS with the volume of prescriptions dispensed was not statistically significant. Conclusions and Relevance: These findings suggest that the implementation of the New Mexico NCS law was successful in lowering out-of-pocket spending on prescription medications for MH/SUDs, but that there was no association of NCS with the volume of medications dispensed in the first 6 months after implementation. A key challenge is to identify policies that protect from high out-of-pocket spending while also promoting access to needed care.