On August 24, 2026, the United States District Court for the Southern District of California (the "Court") preliminarily approved the settlement ("Settlement") of the stockholder derivative action captioned Kanner et al. v. Biggar et al., Case No. 3:23-cv-02293-WQH-MSB. Pursuant to the Court’s order granting preliminary approval of the Settlement, Acadia Pharmaceuticals Inc. (the "Company") is required to publish the Notice of Pendency and Proposed Settlement of Derivative Matters (the "Notice"), attached hereto as Exhibit 99.1, and the Stipulation and Agreement of Settlement (the "Stipulation"), attached hereto as Exhibit 99.2. The Notice and the Stipulation are available for review on the Investor Relations section of the Company’s website at ir.acadia.com.