<SUBMISSION>
<ACCESSION-NUMBER>0001179044-04-000105
<TYPE>3
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20040526
<FILING-DATE>20040526
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>WALTON ALAN G
<CIK>0001214273
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>3
<ACT>34
<FILE-NUMBER>000-50768
<FILM-NUMBER>04833547
</FILING-VALUES>
<MAIL-ADDRESS>
<STREET1>ALEXANDRIA REAL ESTATE EQUITIES INC
<STREET2>135 N LOS ROBLES AVE SUITE 250
<CITY>PASADENA
<STATE>CA
<ZIP>91101
</MAIL-ADDRESS>
</REPORTING-OWNER>
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>ACADIA PHARMACEUTICALS INC
<CIK>0001070494
<ASSIGNED-SIC>2834
<IRS-NUMBER>061376651
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>3911 SORRENTO VALLEY BLVD
<CITY>SAN DIEGO
<STATE>CA
<ZIP>92121
<PHONE>858-558-2871
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>3911 SORRENTO VALLEY BLVD
<CITY>SAN DIEGO
<STATE>CA
<ZIP>92121
</MAIL-ADDRESS>
</ISSUER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2004-05-26</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001070494</issuerCik>
        <issuerName>ACADIA PHARMACEUTICALS INC</issuerName>
        <issuerTradingSymbol>ACAD</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001214273</rptOwnerCik>
            <rptOwnerName>WALTON ALAN G</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>315 POST ROAD WEST</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>WESTPORT</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06880</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Series F Convertible Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F3"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2291667</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Oxford Bioscience Partners IV L.P.</value>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Series F Convertible Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F3"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>23148</value>
                    <footnoteId id="F5"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By mRNA Fund II, L.P.</value>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>1.08</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2004-06-07</value>
            </exerciseDate>
            <expirationDate>
                <value>2013-06-13</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>4500</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">These securities are preferred stock of the issuer and do not have an expiration date.</footnote>
        <footnote id="F2">Immediately</footnote>
        <footnote id="F3">1-for-1</footnote>
        <footnote id="F4">Securities held of record by Oxford Bioscience Partners IV L.P. (&quot;OBP IV&quot;).  Dr. Walton, as an individual general partner of OBP Management IV L.P., the sole general partner of OBP IV may be deemed to beneficially own the shares held of record by OBP IV.  Dr. Walton disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein.</footnote>
        <footnote id="F5">Securities held of record by mRNA Fund II L.P. (&quot;mRNA&quot;).  Dr. Walton, as an individual general partner of OBP Management IV L.P., the sole general partner of mRNA, may be deemed to beneficially own the shares held of record by mNRA.  Dr. Walton disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Alan G. Walton</signatureName>
        <signatureDate>2004-05-26</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
