NPI registry status
Active
2026 NPPES data Addiction Psychiatry Physician NPI 1477751741 M.D.
Verify on CMS → William Mains, M.D.
Addiction Psychiatry Physician in Oakland, California.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 666 in Addiction Psychiatry Physician, and covers specialty classification, practice address, and Medicare Part D prescribing data when reported. According to CMS, every field reflects the provider's official federal registration, see our methodology.
Federal data, no proprietary rating.
We show these CMS records as-is - no composite score, no star rating, no editorial opinion layered on top.
Prescribing volume
796
Medicare Part D claims · 32 beneficiaries · Addiction Psychiatry Physician avg: 792
Generic prescribing
94%
generic claims · 6% brand-name · higher generic rates reduce patient out-of-pocket costs
Source: CMS Medicare Part D Prescriber Public Use File, 2023
Compiled from official public sources by the PlainDoctor editorial team.
What the federal data shows
William Mains, M.D. filed 796 Medicare Part D claims in 2023 as a Addiction Psychiatry Physician in Oakland, California, prescribing 94% generic.
- 796
- Part D claims, 2023
- 94%
- generic prescribing
Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) - no proprietary rating or editorial opinion is applied.
William Mains, M.D.'s Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
796 Top 29% higher than 71% of 1,370,886 prescribers
Each bar is a band; taller bars hold more prescribers. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source CMS Medicare Part D Prescriber Public Use File · 2023
◑
Board-eligible specialty (heuristic, not verified)
William Mains, M.D. practices in an ABMS-board-eligible specialty but we don't have enough CMS-participation signals to confirm active board-certified status. Consult CertificationMatters.org (the official ABMS public lookup).
What does the federal data show about William Mains, M.D.?
Quality data not reportedPrimary specialty
Addiction Psychiatry Physician
Medicare Part D claims
796 1% vs specialty avg
Specialty distribution in California
How Addiction Psychiatry Physician compares to other specialties among California providers
Board certification
Not published by CMS
CMS does not publish a per-provider board-certification field in NPPES. PlainDoctor does not have a reliable per-specialty certification rate to show for Addiction Psychiatry Physician. Verify directly:
How MIPS and board certification work
The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.
Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).
William Mains, M.D. appears in the CMS NPPES registry as an Addiction Psychiatry Physician provider holding M.D. credentials at 7200 BANCROFT AVE, Oakland, CA, 94605, with a listed phone of (510) 553-8500. NPI 1477751741 was issued on 07/06/2007.
Medicare Part D records for calendar year 2023 show 796 prescription claims written by this provider, covering 32 Medicare beneficiaries and totaling roughly $170K in drug spend, split 6% brand-name and 94% generic by claim count.
Addiction Psychiatry Physician is a narrow specialty nationwide, with 666 enrolled providers across 49 states and an average of 792 Part D claims per prescriber, so the context for interpreting these metrics differs meaningfully from a primary-care baseline.
Important: PlainDoctor is a directory of publicly available government data, not medical advice, a malpractice database, or a quality rating. Inclusion here does not imply a recommendation, and absence of complaints or sanctions on this page does not mean none exist, always verify credentials through the NPPES NPI Registry, your state medical board, and the ABMS or AOA before making healthcare decisions.
Practice Address
Provider Details
| NPI | 1477751741 |
|---|---|
| Specialty | Addiction Psychiatry Physician |
| Credentials | M.D. |
| Gender | Male |
| NPI Issued | 07/06/2007 |
License & disciplinary context - California MBC 2023 annual report
Aggregate state board data only, NOT a determination of any individual provider's status. The figures below describe statewide disciplinary activity across all ~150K California medical licensees in 2023 - they are NOT specific to William Mains, M.D.. To verify William Mains, M.D.'s current license status, search the MBC public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.
576
Total board actions, California 2023
Across 556 cases
3.84
Actions per 1,000 licensees
California statewide rate
probation
Most common action type
186 cases
MBC publishes annual disciplinary statistics as part of public-record reporting under each state's Administrative Procedure Act. See the full breakdown by action type and year on the California disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.
Brand vs generic prescribing mix · Generic-heavy
William Mains, M.D. - brand share 6.0%
Addiction Psychiatry Physician average
6% brand-name claims vs 94% generic, on 796 2023 Medicare Part D claims.
The federal Medicare Part D Generic Dispensing Rate national benchmark sits near 90% generic / 10% brand for primary-care prescribers, per CMS Office of the Actuary 2024 estimates. Higher brand share is common in specialty prescribing where generic equivalents are not available.
Medicare Part D Prescribing Data
CMS Medicare Part D prescriber-level data for calendar year 2023.
796
Total Claims
$170K
Total Drug Cost
32
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 820
- Total Day Supply
- 22,955
- Brand vs Generic
- 6% brand / 94% generic
- Brand Drug Cost
- $126K
- Generic Drug Cost
- $44K
Patient Demographics
- Average Patient Age
- 46.9 years
- Avg HCC Risk Score
- 1.17
- Gender Split
- 34% female / 66% male
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What William Mains, M.D. prescribes most
Top Medicare Part D drugs by claim count, 2023
- Olanzapine
Olanzapine
181 claims
- Aripiprazole 62
Aripiprazole
62 claims
- Risperidone 55
Risperidone
55 claims
- Gabapentin 44
Gabapentin
44 claims
- Divalproex Sodium Er 38
Divalproex Sodium Er
38 claims
- Mirtazapine 38
Mirtazapine
38 claims
- Haloperidol 33
Haloperidol
33 claims
- Benztropine Mesylate 25
Benztropine Mesylate
25 claims
| Drug | Claims |
|---|---|
| Olanzapine | 181 |
| Aripiprazole | 62 |
| Risperidone | 55 |
| Gabapentin | 44 |
| Divalproex Sodium Er Divalproex Sodium | 38 |
| Mirtazapine | 38 |
| Haloperidol | 33 |
| Benztropine Mesylate | 25 |
| Fluoxetine Hcl | 25 |
| Trihexyphenidyl Hcl | 25 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Addiction Psychiatry Physician Overview
How William Mains, M.D. fits within the Addiction Psychiatry Physician landscape nationally.
666
Addiction Psychiatry Physician Providers in US
49
States with Addiction Psychiatry Physician
792
Avg Claims per Provider
William Mains, M.D.'s 796 claims are above the specialty average of 792.
Nearby Addiction Psychiatry Physician Providers in California
Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as Mains.
Dr. Steven Allen
M.D.
Sylmar, CA
Dr. Eva Altobelli
MD
Santa Monica, CA
Dr. Rod Amiri
MD
Calabasas, CA
Dr. Robert Anthenelli
M.D.
San Diego, CA
Dr. Navdeep Baath
M.D.
Santa Cruz, CA
Compare Addiction Psychiatry Physician nationally: see state-by-state distribution →
Before you book an appointment
Use this federal record as your verification checklist, not as a recommendation.
- Confirm the NPI record is current in the official CMS registry, providers update their own NPPES details, and moves can lag. Verify this NPI
- Check the active license and any disciplinary history with the California medical board, federal registration is not a license check. Credential verification guide
- Weigh a second option: compare this provider with a nearby Addiction Psychiatry Physician peer on Medicare volume and prescribing patterns. Compare providers
Medicare Part D and MIPS figures describe practice patterns in federal programs only, they are not quality ratings, and PlainDoctor does not rate, rank, or recommend providers.
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Frequently Asked Questions
What is William Mains, M.D.'s specialty? ▼
William Mains, M.D. specializes in Addiction Psychiatry Physician and practices in Oakland, California. Credentials: M.D..
How much does William Mains, M.D. prescribe under Medicare Part D? ▼
In 2023, William Mains, M.D. wrote 796 Medicare Part D claims totaling $170K in drug costs for 32 beneficiaries.
Where is William Mains, M.D. located? ▼
William Mains, M.D. is located at 7200 BANCROFT AVE, Oakland, CA, 94605. Phone: (510) 553-8500.
What is William Mains, M.D.'s NPI number? ▼
William Mains, M.D.'s National Provider Identifier (NPI) is 1477751741, issued on 07/06/2007.
Does William Mains, M.D. prescribe more brand-name or generic drugs? ▼
William Mains, M.D.'s prescribing is 6% brand-name and 94% generic drugs by claim count, with $126K in brand drug costs.
How many Addiction Psychiatry Physician providers are there in the US? ▼
There are 666 Addiction Psychiatry Physician providers across 49 states in the US. The average Addiction Psychiatry Physician provider writes 792 Medicare Part D claims per year.
What drugs does William Mains, M.D. prescribe most often? ▼
Based on 2023 Medicare Part D data, William Mains, M.D.'s most frequently prescribed drugs include Olanzapine, Aripiprazole, Risperidone. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does William Mains, M.D. accept Medicare? ▼
William Mains, M.D. appears in CMS Medicare data with 796 Part D claims and 32 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify William Mains, M.D.'s credentials? ▼
William Mains, M.D.'s NPI is 1477751741 with credentials M.D.. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.
Data Sources
View source datasets and methodology notes
- Provider Directory
- CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
- Specialty Classification
- NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
- Prescribing Data
- CMS Medicare Part D Prescriber Public Use File (2023). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
- Limitations
- Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.
See our complete data methodology for details on how we collect and process government data.
Data as of April 2026 (NPPES) / 2023 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).
Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology
Compiled from official public sources by the PlainDoctor editorial team.
Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of May 2026.