ACADIA Pharmaceuticals Adds Complementary Intellectual Property for Serotonin Platform.

SAN DIEGO -- ACADIA Pharmaceuticals Inc. (Nasdaq:ACAD), a biopharmaceutical company utilizing innovative technology to fuel drug discovery and clinical development of novel treatments for central nervous system disorders, today announced that it has expanded and further strengthened the intellectual property portfolio for its serotonin platform by entering into an agreement to license certain intellectual property rights from Ipsen (Euronext:IPN), an innovation driven international specialty pharmaceutical group.

ACADIA has developed a broad serotonin platform comprising a range of chemistries and biological assets. These assets include ACP-103 and follow-on and back-up compounds, which have potential therapeutic applications in a number of CNS indications, including schizophrenia, Parkinson's disease psychosis, and sleep maintenance insomnia. ACADIA's intellectual property estate in the serotonin area currently includes 11 issued patents and 81 pending patent applications. The Ipsen agreement provides ACADIA with a non-exclusive license to additional intellectual property rights that complement this serotonin patent portfolio. Under the terms of the agreement, ACADIA will make an initial payment of $250,000 to Ipsen, and, if certain conditions are met, ACADIA would make additional payments, including milestones, royalties and sublicensing fees for compounds covered by the agreement.

About ACADIA Pharmaceuticals

ACADIA is a biopharmaceutical company utilizing innovative technology to fuel drug discovery and clinical development of novel treatments for central nervous system disorders. ACADIA currently has five Phase II-stage clinical programs as well as a portfolio of preclinical and discovery assets directed at diseases with large unmet medical needs, including schizophrenia, Parkinson's disease psychosis, sleep maintenance insomnia, and neuropathic pain. All of the drug candidates in ACADIA's product pipeline emanate from discoveries made using its proprietary drug discovery platform. ACADIA's corporate headquarters is located in San Diego, California and it maintains research and development operations in both San Diego and MalmE, Sweden.

Forward-Looking Statements

Statements in this press release that are not strictly historical in nature are forward-looking statements. These statements include but are not limited to statements related to the potential benefits to be derived from ACADIA's programs and compounds, benefits to be derived from the license agreement, and future payments that may be made pursuant to the license agreement. These statements are only predictions based on current information and expectations and involve a number of risks and uncertainties. Actual events or results may differ materially from those projected in any of such statements due to various factors, including the risks and uncertainties inherent in drug discovery, development and commercialization. For a discussion of these and other factors, please refer to ACADIA's annual report on Form 10-K for the year ended December 31, 2005 as well as other subsequent filings with the Securities and Exchange Commission. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof. This caution is made under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. All forward-looking statements are qualified in their entirety by this cautionary statement and ACADIA undertakes no obligation to revise or update this press release to reflect events or circumstances after the date hereof.