Nathan Rhys Gwilliam, MD

Primary specialty

Psychiatry PhysicianTaxonomy code 2084P0800X

License

71782 Issued in CT

Practice address

389 Whitney Ave
Whitney Office Suites #2
New Haven, CT 06511

Phone

(203) 293-6258

NPI assigned

Jul 3, 2013

Sex

Male

Sole proprietor

Yes

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

Specialties & licenses 1

Addresses

Medicare fee-for-service enrollment

Enrolled in CT

Eligible to order & refer

• Part B services: Yes
• Medical equipment: Yes
• Home health: Yes
• Power mobility devices: Yes
• Hospice: Yes

Green means eligible to order or refer.

Enrollment records 1

Specialty

Psychiatry

Education

Baylor College of Medicine, 2012

Medicare assignment

Accepts the Medicare-approved amount as payment in full

Group practices

Middlesex HospitalGroup PAC ID 5092611731, shared by 7 NPIs, 231 clinicians

Practice addresses (Care Compare)

Hospital & facility affiliations

• Middlesex Hospital Hospital, Middletown, CT, CCN 070020

Medicare enrollment (NPD)

Enrolled

Credentials

Doctor of Medicine

State licenses

Practice roles

Locations

Interoperability endpoints

• Direct secure messaging: ngwilliam90526@middlesexhealthprd.direct-ci.com

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

• Middlesex Hospital

  dba Middlesex Hospital dba Middlesex Hospital Psychiatric Physician Servic

  • Psychiatry Physician
  • Middletown, CT
  • NPI 1760451041
  Medicare reassignment NPD
• Middlesex Hospital

  • General Acute Care Hospital
  • Middletown, CT
  • NPI 1760454334
  Medicare reassignment NPD
• Connecticut Pathology Group PC

  • Anatomic Pathology & Clinical Pathology Physician
  • Middletown, CT
  • NPI 1740219625
  NPD
• Middlesex Hospital

  dba Middlesex Hospital Homecare and Hospice

  • Community Based Hospice Care Agency
  • Middletown, CT
  • NPI 1003873233
  NPD
• Middlesex Hospital

  dba Middlesex Hospital Ambulance Service

  • Land Ambulance
  • Middletown, CT
  • NPI 1710370390
  NPD (past)

Hospitals and other facilities this clinician is affiliated with according to Medicare Care Compare.

• Middlesex Hospital

  • General Acute Care Hospital
  • Middletown, CT
  • NPI 1760454334
  Care Compare affiliation

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

{
    "created_epoch": "1372809600000",
    "enumeration_type": "NPI-1",
    "last_updated_epoch": "1775433600000",
    "number": "1366882409",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "389 WHITNEY AVE",
            "address_2": "WHITNEY OFFICE SUITES #2",
            "city": "NEW HAVEN",
            "state": "CT",
            "postal_code": "06511",
            "telephone_number": "203-293-6258"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "389 WHITNEY AVE",
            "address_2": "WHITNEY OFFICE SUITES #2",
            "city": "NEW HAVEN",
            "state": "CT",
            "postal_code": "06511",
            "telephone_number": "203-293-6258"
        }
    ],
    "practiceLocations": [],
    "basic": {
        "last_name": "GWILLIAM",
        "first_name": "NATHAN",
        "middle_name": "RHYS",
        "name_prefix": "Dr.",
        "credential": "MD",
        "sole_proprietor": "YES",
        "sex": "M",
        "enumeration_date": "2013-07-03",
        "last_updated": "2026-04-06",
        "certification_date": "2026-04-06",
        "status": "A"
    },
    "taxonomies": [
        {
            "code": "2084P0800X",
            "taxonomy_group": "",
            "desc": "Psychiatry & Neurology, Psychiatry",
            "state": "CT",
            "license": "71782",
            "primary": true
        }
    ],
    "identifiers": [],
    "endpoints": [],
    "other_names": []
}

• Danya R Guttman, LPC
• Maria Elizabeth Guzman, PSY.D
• Raul J. Guzman, M.D.
• John Guzzi, MD
• Meghan Elizabeth Gwara, PA-C
• Helen Gyamfi, LPC
• James T Ha, MD
• Aamil Haameem, M.D
• Linda Haas
• Mailee Haas, PT, DPT

• Psychiatry Physician in New Haven, CT
• Providers in New Haven, CT by specialty
• Psychiatry Physician in Connecticut

• NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Apr 6, 2026; self-reported and not verified by CMS. Specialty names from the NUCC taxonomy.
• Medicare enrollment (CMS PECOS): enrollments, PAC IDs and benefit reassignments; Order and Referring.
• Medicare Care Compare (CMS): clinician profile, group practices, facility affiliations, MIPS scores and star ratings.
• National Provider Directory (CMS): practice roles, locations, licenses, networks and endpoints.

Verify at the official NPI Registry.