Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Ms. Adrienne B. Difabio, PHD

Psychologist in Napa, CA · enumerated 2013.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1659702785

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Registry record

Entity type Individual (Type 1)

Name Ms. Adrienne B. Difabio

Credential PHD

Sex Female

Practice address 2100 Napa Vallejo Hwy, Napa, CA, 94558

Phone (707) 253-5000

Fax (707) 253-5097

Enumeration date Nov 27, 2013

Last updated in NPPES Jan 3, 2022

Taxonomy & licenses

103T00000X Psychologist Behavioral Health & Social Service Providers · License PSY25828 (CA) Primary

PHD · Doctor of Philosophy: A doctoral degree; in healthcare often held by clinical psychologists and researchers. About the PHD credential

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

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Frequently asked questions

Is this the official NPI registry?

No. NPI Portal is a private site built on public CMS NPPES data. The official registry is npiregistry.cms.hhs.gov, operated by CMS.

What specialty is Adrienne Difabio?

Adrienne Difabio is registered in NPPES with the primary taxonomy of Psychologist. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2022-01-03.