ACADIA PHARMACEUTICALS INC. 2004 EMPLOYEE STOCK PURCHASE PLAN ADOPTED BY THE BOARD OF DIRECTORS ON FEBRUARY 25, 2004 APPROVED BY STOCKHOLDERS ON MAY 5, 2004 AMENDED BY THE BOARD OF DIRECTORS ON APRIL 29, 2016 APPROVED BY

ACADIA PHARMACEUTICALS INC.

2004 EMPLOYEE STOCK PURCHASE PLAN

ADOPTED BY THE BOARD OF DIRECTORS ON FEBRUARY 25, 2004

APPROVED BY STOCKHOLDERS ON MAY 5, 2004

AMENDED BY THE BOARD OF DIRECTORS ON APRIL 29, 2016

STOCKHOLDERS ON JUNE 10, 2016

AMENDED BY THE BOARD OF DIRECTORS: APRIL 27, 2019

APPROVED BY THE STOCKHOLDERS: JUNE 26, 2019

AMENDED BY THE BOARD OF DIRECTORS: APRIL 28, 2020

STOCKHOLDERS: JUNE 23, 2020

(a) The purpose of the Plan is to provide a means by which Employees of the Company and certain designated Related Corporations may be given an opportunity to purchase shares of the Common

Stock of the Company.

(b) The Company, by means of the Plan, seeks to retain the services of such Employees, to

secure and retain the services of new Employees and to provide incentives for such persons to exert maximum efforts for the success of the Company and its Related Corporations.

(c) The Company intends that the Purchase Rights be considered options issued under an Employee Stock Purchase Plan.

As used in the Plan and any Offering, unless otherwise specified, the following terms have the meanings set forth below:

(a) Annual Meeting means the annual meeting of the stockholders of the Company.

(b) Board means the Board of Directors of the Company.

(c) Code means the Internal Revenue Code of 1986, as amended.

(d) Committee means a committee appointed by the Board in accordance with

Section 3(c) of the Plan.

(e) Common Stock means the common stock of the

(f) Company means ACADIA Pharmaceuticals Inc., a Delaware corporation.

(g) Contributions means the payroll deductions and other additional payments that

a Participant contributes to fund the exercise of a Purchase Right. A Participant may make payments not through payroll deductions only if specifically provided for in the Offering, and then only if the Participant has not already had the maximum

permitted amount withheld through payroll deductions during the Offering.

Transaction means the occurrence, in a single transaction or in a series of related transactions, of any one or more of the following events:

(i) a sale, exchange, lease, license or other disposition of all or

substantially all of the consolidated assets of the Company;

(ii) a sale, exchange or other disposition of more

than fifty percent (50%) of the outstanding securities of the Company;

(iii) a merger, consolidation or similar

transaction following which the Company is not the surviving corporation; or

(iv) a merger, consolidation or

similar transaction following which the Company is the surviving corporation but the shares of Common Stock outstanding immediately preceding the merger, consolidation or similar transaction are converted or exchanged by virtue of the merger,

consolidation or similar transaction into other property, whether in the form of securities, cash or otherwise.

(i) Director means a member of the Board.

(j) Eligible Employee means an Employee who meets the requirements set forth in the

Offering for eligibility to participate in the Offering, provided that such Employee also meets the requirements for eligibility to participate set forth in the Plan.

(k) Employee means any person, including Officers and Directors, who is employed for purposes of Section 423(b)(4) of the Code by the Company or a

Related Corporation. Neither service as a Director nor payment of a director s fee shall be sufficient to make an individual an Employee of the Company or a Related Corporation.

(l) Employee Stock Purchase Plan means a plan that grants Purchase Rights intended to

be options issued under an employee stock purchase plan, as that term is defined in Section 423(b) of the Code.

(m) Exchange Act means the Securities Exchange Act of 1934, as amended.

(n) Fair Market Value means the value of a security, as determined in good faith by the Board. If the security is listed on any established stock exchange

or traded on the Nasdaq National Market or the Nasdaq SmallCap Market, the Fair Market Value of the security, unless otherwise determined by the Board, shall be the closing sales price (rounded up where necessary to the nearest whole

cent) for such security (or the closing bid, if no sales were reported) as quoted on such exchange or market (or the exchange or market with the greatest volume of trading in the relevant security of the Company) on the Trading Day prior to the

relevant determination date, as reported in The Wall Street Journal or such other source as the Board deems reliable.

(o) IPO Date means the effective date of the initial public offering of the Common Stock.

(p) Offering means the grant of Purchase Rights to purchase shares of Common Stock

under the Plan to Eligible Employees.

(q) Offering Date means a date selected by

the Board for an Offering to commence.

person who is an officer of the Company within the meaning of Section 16 of the Exchange Act and the rules and regulations promulgated thereunder.

(s) Participant means an Eligible Employee

who holds an outstanding Purchase Right granted pursuant to the Plan.

(t) Plan means this ACADIA Pharmaceuticals Inc. 2004 Employee Stock Purchase Plan.

(u) Purchase Date means one or more dates during an Offering established by

the Board on which Purchase Rights shall be exercised and as of which purchases of shares of Common Stock shall be carried out in accordance with such Offering.

(v) Purchase Period means a period of time specified within an Offering beginning on the Offering Date or on the next day following a Purchase Date within an

Offering and ending on a Purchase Date. An Offering may consist of one or more Purchase Periods.

(w) Purchase Right means an option to purchase shares of Common Stock granted pursuant

(x) Related Corporation means any parent corporation or

subsidiary corporation, whether now or hereafter existing, as those terms are defined in Sections 424(e) and (f), respectively, of the Code.

(y) Securities Act means the Securities Act of 1933, as amended.

(z) Trading Day means any day on which the exchange(s) or market(s) on which shares of Common Stock are listed, whether it be an established stock

exchange, the Nasdaq National Market, the Nasdaq SmallCap Market or otherwise, is open for trading.

(a) The Board shall administer the Plan unless and until the Board delegates administration to a Committee, as provided in Section 3(c). Whether or not the Board has delegated

administration, the Board shall have the final power to determine all questions of policy and expediency that may arise in the administration of the Plan.

(b) The Board (or the Committee) shall have the power, subject to, and within the limitations of, the express provisions of the Plan:

(i) To determine when and how Purchase Rights to purchase shares of Common Stock shall be granted and the provisions of each

Offering of such Purchase Rights (which need not be identical).

(ii) To designate from time to time which Related

Corporations of the Company shall be eligible to participate in the Plan.

(iii) To construe and interpret the

Plan and Purchase Rights, and to establish, amend and revoke rules and regulations for the administration of the Plan. The Board, in the exercise of this power, may correct any defect, omission or inconsistency in the Plan, in a manner and to the

extent it shall deem necessary or expedient to make the Plan fully effective.

(iv) To amend the Plan as provided

(v) Generally, to exercise such powers and to perform such acts as it deems

necessary or expedient to promote the best interests of the Company and its Related Corporations and to carry out the intent that the Plan be treated as an Employee Stock Purchase Plan.

(vi) To adopt such procedures and sub-plans as are necessary or appropriate to

permit participation in the Plan by Employees who are foreign nationals or employed outside the United States.

(c) The Board may delegate administration of the Plan to a Committee of the Board composed of one (1) or more members of

the Board. If administration is delegated to a Committee, the Committee shall have, in connection with the administration of the Plan, the powers theretofore possessed by the Board, subject, however, to such resolutions, not inconsistent with the

provisions of the Plan, as may be adopted from time to time by the Board. The Board may abolish the Committee at any time and revest in the Board the administration of the Plan. If administration is delegated to a Committee, references to the Board

in this Plan and in the Offering document shall thereafter be deemed to be to the Board or the Committee, as the case may be.

(d) All determinations, interpretations and constructions made by the Board in good faith shall not be subject to review by

any person and shall be final, binding and conclusive on all persons.

(a) Subject to the provisions of Section 14 relating to adjustments upon changes in stock after the IPO Date, the shares of Common Stock that may be sold pursuant to Purchase Rights shall

not exceed in the aggregate 5,525,000 shares of Common Stock.

(b) The shares of Common Stock subject to the Plan

may be unissued shares or shares that have been bought on the open market at prevailing market prices or otherwise.

(a) The Board may from time to time grant or provide for the grant of Purchase Rights to purchase shares of Common Stock under the Plan to Eligible Employees in an Offering (consisting of one

or more Purchase Periods) on an Offering Date or Offering Dates selected by the Board. Each Offering shall be in such form and shall contain such terms and conditions as the Board shall deem appropriate, which shall comply with the requirement of

Section 423(b)(5) of the Code that all Employees granted Purchase Rights shall have the same rights and privileges. The terms and conditions of an Offering shall be incorporated by reference into the Plan and treated as part of the Plan. The

provisions of separate Offerings need not be identical, but each Offering shall include (through incorporation of the provisions of this Plan by reference in the document comprising the Offering or otherwise) the period during which the Offering

shall be effective, which period shall not exceed twenty-seven (27) months beginning with the Offering Date, and the substance of the provisions contained in Sections 6 through 9, inclusive.

(b) If a Participant has more than one Purchase Right outstanding under the Plan, unless he or she otherwise indicates in

agreements or notices delivered hereunder: (i) each agreement or notice delivered by that Participant shall be deemed to apply to all of his or her Purchase Rights under the Plan, and (ii) a Purchase Right with a lower exercise price (or

an earlier-granted Purchase Right, if different Purchase Rights have identical exercise prices) shall be exercised to the fullest possible extent before a Purchase Right with a higher exercise price (or a later-granted Purchase Right if different