NPPES file of Aug 9, 2026

William Roy Mains, M.D.

Addiction Psychiatry Physician · Oakland, CA

William Roy Mains, M.D. is an addiction psychiatry physician with a practice address in Oakland, California, and NPI 1477751741, issued on Jul 6, 2007. Check the license (California A65356, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.

Record from CMS NPPES, file of Aug 9, 2026 · Medicare files 2024 · method · Verify with CMS →

NPPES recordNPPES file of Aug 9, 2026
1477751741
Name
William Roy Mains
Credential
M.D.
Primary taxonomy
Addiction Psychiatry Physician 2084P0802X
License number
A65356 CA
Self-reported in NPPES; status is on the state search
Practice location
7200 Bancroft Ave, Oakland, CA 94605
Phone
(510) 553-8500
Enumerated
Jul 6, 2007
Record last updated
Jan 7, 2010 (not updated in 16 years: call before relying on the address or phone)
Fax
(510) 553-8550
Medicare enrollment
Enrolled (PECOS I20040914001391); accepts Medicare assignment
Medical or professional school
University Of California, San Diego School Of Medicine, 1996
Telehealth
Offers telehealth (CMS)
Entity
Type 1 · individual
Public record from CMS NPPES (open it on the CMS NPI Registry). Enrollment, assignment, school and telehealth: CMS Doctors and Clinicians file, Aug 2026. A record is not a license: verify it with the state board.
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Also registered at 7200 Bancroft Ave

A shared address usually means a shared clinic or building; it does not show who employs whom.

  1. Mia AcostaMarriage & Family Therapist1841880242
  2. Albert Almondia, ASWClinical Social Worker1275744013
  3. Alganesh Andemariam, RNCase Management Registered Nurse1871777425
  4. Josefine AndinoCommunity Health Worker1740641869
  5. Binh AuSocial Worker1932637915
  6. Ladan Bandi AmirabadStudent in an Organized Health Care Education/Training Program1912672700

Verify William Roy Mains in five checks

  1. 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
  2. 2LicenseActive license and public ordersMedical Board of California
    Search for license A65356
    Check the board
  3. 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
  4. 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
  5. 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
Open the California license search

PlainDoctor does not match the HHS-OIG exclusion list to individual records: most entries carry no NPI. Search the OIG exclusion list by name.

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5% more Medicare Part D claims than the average addiction psychiatry physician in 2024

750 Medicare Part D claims for 33 beneficiaries, against an average of 716 among the 421 providers of this specialty who prescribed in Part D. Brand-name drugs were 7% of claims.

  1. William Mains750
  2. Specialty average716

Most prescribed

  1. Olanzapine126 claims
  2. Aripiprazole63 claims
  3. Gabapentin46 claims
  4. Risperidone40 claims
  5. Mirtazapine37 claims
  6. Fluoxetine Hcl32 claims

Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.

William Roy Mains among 73 addiction psychiatry physician records in California

William Roy Mains, M.D. is one of 73 addiction psychiatry physician records with a practice address in California. 73% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2007, is newer than 42% of them.

  • NPI issued2007 · 42% of these records are older, 41% newer
  • In a Medicare fileYes · 73% of these records are
  • In the CMS Doctors and Clinicians fileYes · 34% of these records are
  • Graduated1996 · median 2008 among the 25 with a school on file
  • Record last updated2010 · 56% of these records were not updated in five years or more

Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 2084P0802X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).

Addiction Psychiatry Physician providers in California

There are 73 addiction psychiatry physician records in California.

The 8 addiction psychiatry physician records with the nearest ZIP codes

  1. William Brostoff, MDVallejo, CA 945891467530352
  2. Maralee Joseph, MDVallejo, CA 945891922186766
  3. Monika Koch, MDVallejo, CA 945891568534212
  4. Vicki Kalira, M.D.Martinez, CA 945531124342647
  5. Alison Jacobi, MDAntioch, CA 945091821176983
  6. Daniel Notzon, M.D.San Rafael, CA 949031992949457
  7. James Armontrout, MDPalo Alto, CA 943041215202403
  8. Smita Das, MD, PHD, MPHPalo Alto, CA 943041114219870

Common questions

What is William Roy Mains, M.D.'s NPI number?

William Roy Mains, M.D.'s National Provider Identifier (NPI) is 1477751741, issued on Jul 6, 2007. An NPI identifies a provider in billing; it is not a license.

Where is William Roy Mains, M.D. located?

The NPPES record lists a practice address at 7200 Bancroft Ave, Oakland, CA, 94605. Phone: (510) 553-8500. Providers update this record themselves, so call before visiting.

How can I verify William Roy Mains, M.D.'s license?

NPPES lists California license number A65356, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.

How much does William Roy Mains, M.D. prescribe under Medicare Part D?

In 2024, William Roy Mains, M.D. had 750 Medicare Part D claims for 33 beneficiaries; the average among addiction psychiatry physician prescribers was 716. Part D covers Medicare prescriptions only.

Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.

Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.