Thalia Pitsillidou Sullivan Nicholson, PHD

Primary specialty

PsychologistTaxonomy code 103T00000X

License

35995 Issued in CA

Practice address

140 Pine St
Auburn, CA 95603-5247

Phone

(530) 423-3714

NPI assigned

Jul 7, 2021

Last updated

Feb 26, 2026By the provider in NPPES

Sex

Female

Sole proprietor

No

Registry information is reported by the provider to CMS and is not verified. About this source

Specialties & licenses 2

Addresses

Medicare fee-for-service enrollment

Not listed in the public Medicare enrollment file

Opted out of Medicare

Yes, effective Feb 17, 2026 through Feb 17, 2028

Medicare enrollment (NPD)

Not enrolled

Credentials

Doctor of Philosophy

State licenses

Practice roles

Organizations this provider is connected to: Medicare benefit reassignments (the organization bills Medicare for this provider’s services), Care Compare group memberships, National Provider Directory roles and organizations whose NPPES authorized official is this provider.

• Thalia Nicholson Psychological Services, Inc.

  dba America's First Responder Services

  • Clinical Psychologist
  • Roseville, CA
  • NPI 1255292025
  NPD Authorized official

The complete NPPES record for this NPI in the NPI Registry API format.

{
    "created_epoch": "1625616000000",
    "enumeration_type": "NPI-1",
    "last_updated_epoch": "1772064000000",
    "number": "1760053136",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "5701 LONETREE BLVD STE 113",
            "city": "ROCKLIN",
            "state": "CA",
            "postal_code": "957653792",
            "telephone_number": "530-423-3714"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "140 PINE ST",
            "city": "AUBURN",
            "state": "CA",
            "postal_code": "956035247",
            "telephone_number": "530-423-3714"
        }
    ],
    "practiceLocations": [],
    "basic": {
        "last_name": "SULLIVAN NICHOLSON",
        "first_name": "THALIA",
        "middle_name": "PITSILLIDOU",
        "credential": "PHD",
        "sole_proprietor": "NO",
        "sex": "F",
        "enumeration_date": "2021-07-07",
        "last_updated": "2026-02-26",
        "certification_date": "2026-02-26",
        "status": "A"
    },
    "taxonomies": [
        {
            "code": "103T00000X",
            "taxonomy_group": "",
            "desc": "Psychologist",
            "state": "CA",
            "license": "35995",
            "primary": true
        },
        {
            "code": "103T00000X",
            "taxonomy_group": "",
            "desc": "Psychologist",
            "state": "NV",
            "license": "1300",
            "primary": false
        }
    ],
    "identifiers": [],
    "endpoints": [],
    "other_names": []
}

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• Psychologist in Auburn, CA
• Providers in Auburn, CA by specialty
• Psychologist in California

• NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Feb 26, 2026; self-reported and not verified by CMS. Specialty names from the NUCC taxonomy.
• Medicare enrollment (CMS PECOS): enrollments, PAC IDs and benefit reassignments; Opt Out Affidavits.
• National Provider Directory (CMS): practice roles, locations, licenses, networks and endpoints.

Verify at the official NPI Registry.