Exhibit 23.3

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in this Registration Statement on Form S-3 of our report dated March 17, 2025 relating to the financial statements of ATAI Life Sciences N.V., appearing in the Annual Report on Form 10-K of ATAI Life Sciences N.V. for the year ended December 31, 2024. We also consent to the reference to us under the heading "Experts" in such Registration Statement.

/s/ Deloitte & Touche LLP

Morristown, New Jersey

September 29, 2025