Deidre Williams, MD
NPI 1366604209 · Psychiatry Physician · Cupertino, CA
Enrolled with Medicare as Practitioner - Psychiatry · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Deidre Williams, MD is a Psychiatry Physician provider in Cupertino, CA (NPI 1366604209).
Provider details
- NPI number
- 1366604209
- Entity type
- Individual
- Primary specialty
- Psychiatry PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Female
- Sole proprietor
- No
- License
- A106036 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
17 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
1 documented practice location
Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 23 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Mirtazapine | 104 | 33 |
| Bupropion Hclbrand: Bupropion Xl | 94 | 27 |
| Sertraline Hcl | 71 | 28 |
| Olanzapine | 63 | 16 |
| Gabapentin | 56 | 17 |
| Fluoxetine Hcl | 51 | 15 |
| Trazodone Hcl | 46 |
Practice location
Mailing address
Registry dates
- Enumerated
- 2008-07-01
- Last updated
- 2022-01-10
Frequently asked questions
- What is Deidre Williams's NPI number?
- Deidre Williams's National Provider Identifier (NPI) is 1366604209, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Deidre Williams's specialty?
- Deidre Williams is listed in the NPPES registry with a primary specialty of Psychiatry Physician (Allopathic & Osteopathic Physicians).
- Where is Deidre Williams located?
- Deidre Williams's practice location on file with NPPES is 19000 Homestead Rd, Cupertino, CA 95014-0712.
- What is Deidre Williams's phone number?
- The practice phone number listed in the NPPES registry for Deidre Williams is (408) 366-4400.
- Does Deidre Williams accept Medicare?
- Deidre Williams is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Deidre Williams's NPI active?
- Yes — Deidre Williams's NPI (1366604209) is active in the NPPES registry as of the last update on 2022-01-10.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.