Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T duringthe preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes☒No☐ Indicate by check mark whether the registrant is a large accelerated filed, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growthcompany. See definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company”, and “emerging growth company” in Rule 12b-2 of the Exchange Act. If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financialaccounting standards provided pursuant to Section 13(a) of the Exchange Act.☐Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financialreporting under Section 404(b) of the Sarbanes-Oxley (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report.☒If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect thecorrection of an error to previously issued financial statements.☐Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of theregistrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b).☐Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes☐No☒The aggregate market value of voting common stock held by non-affiliates of the registrant (assuming for purposes of this calculation, without conceding, that all executiveofficers and directors are “affiliates”) was approximately $4.4 billion as of June 30, 2025, based on the closing sale price of such stock as reported on The Nasdaq Global Market.There were 51,153,289 shares of the registrant’s common stock outstanding as of February 16, 2026.DOCUMENTS INCORPORATED BY REFERENCEPortions of the registrant’s definitive proxy statement for its 2026 Annual Meeting of Stockholders (the “Proxy Statement”), to be filed within 120 days of the registrant’s fiscal year ended December 31, 2025, are incorporated by reference in Part III of this Annual Report on Form 10-K. Except with respect to information specifically incorporated by reference inthis Annual Report on Form 10-K, the Proxy Statement is not deemed to be filed as part of this Annual Report on Form 10-K. AXSOME THERAPEUTICS, INC.ANNUAL REPORT ON FORM 10-KFOR THE FISCAL YEAR ENDED DECEMBER 31, 2025 TABLE OF CONTENTS SPECIAL CAUTIONARY NOTICE REGARDING FORWARD-LOOKING STATEMENTS3 PART I ITEM 1BusinessITEM 1ARisk FactorsITEM 1BUnresolved Staff CommentsITEM 1CCybersecurityITEM 2PropertiesITEM 3Legal ProceedingsITEM 4Mine Safety Disclosures PART II ITEM 5Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of EquitySecurities107ITEM 6Reserved108ITEM 7Management’s Discussion and Analysis of Financial Condition and Results of Operations109ITEM 7AQuantitative and Qualitative Disclosure About Market Risk124ITEM 8Financial Statements and Supplementary Data124ITEM 9Changes in and Disagreements with Accountants on Accounting and Financial Disclosure124ITEM 9AControls and Procedures125ITEM 9BOther Information126ITEM 9CDisclosure Regarding Foreign Jurisdictions that Prevent Inspections126 PART III ITEM 10Directors, Executive Officers and Corporate Governance127ITEM 11Executive Compensation127ITEM 12Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters127ITEM 13Certain Relationships and Related Transactions and Director Independence127ITEM 14Principal Accountant Fees and Services127 PART IV ITEM 15Exhibits and Financial Statement SchedulesITEM 16Form 10-K SummarySignatures 128135136 CAUTIONARY NOTE REGARDING FORWARD‑LOOKING STATEMENTS Certain matters discussed in this report, including matters discussed under the caption “Management’s Discussion andAnalysis of Financial Condition and Results of Operations,” may constitute forward-looking statements for purposes of theSecurities Act of 1933, as amended, or the Securities Act, and the Securities Exchange Act of 1934, as amended, or the ExchangeAct, and involve known and unknown risks, uncertainties and other factors that may cause our actual results, performance orachievements to be materially different from the future results, performance or achievements expressed or implied by such forward-looking statements. The words “anticipate,” “believe,” “estimate,” “may,” “expect” and similar expressions are generally intendedto identify fo