NPI registry status
Active
2026 NPPES data Psychiatry Physician NPI 1639193659 M.D.
Verify on CMS → Christopher Dunham, M.D.
Psychiatry Physician in Chico, 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 54,383 in 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
2K
Medicare Part D claims · 96 beneficiaries · Psychiatry Physician avg: 1K
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, 2024
What the federal data shows
Christopher Dunham, M.D. filed 2,410 Medicare Part D claims in 2024 as a Psychiatry Physician in Chico, California, prescribing 94% generic.
- 2K
- Part D claims, 2024
- 94%
- generic prescribing
- Likely
- board-certified (heuristic)
- ≥86th
- pct by Part D claim volume (lower-bound band)
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.
Federal trust snapshot
What official records show about Christopher Dunham, M.D.
Federal records show an active NPI with Medicare Part D prescribing activity — verifiable registry data, not a proprietary rating.
- Verified
NPI registry status
Active listing in the CMS National Provider Identifier Registry (NPI 1639193659), first enumerated 07/26/2006.
Source: CMS NPPES
- Reported
Medicare Part D participation
Filed 2,410 Medicare Part D prescription claims in the 2023 CMS public use file — indicates active Medicare prescribing participation.
Source: CMS Part D Prescriber PUF
- Reported
Board certification signal
Heuristic suggests board-certified status based on ABMS-eligible specialty taxonomy plus active CMS participation signals — not a direct ABMS verification.
- Reported
Hospital affiliations
1 CMS Care Compare hospital affiliation on record — practice footprint from the Doctors and Clinicians file.
Source: CMS Care Compare
- State context
State board disciplinary context
California statewide board action statistics are published annually — these figures describe aggregate state activity, not Christopher Dunham, M.D.'s individual license status. Verify directly with the state medical board.
Source: MBC annual report 2023
- Not in federal data
Individual sanction lookup
PlainDoctor does not publish per-provider disciplinary determinations. Confirm current license and any individual actions through the state medical board or FSMB verification service.
Source: State medical board / FSMB
This trust snapshot summarizes only what appears in federal CMS/NPPES public records. It is not a composite score, star rating, patient review, or clinical recommendation. PlainDoctor never fabricates reviews or AggregateRating schema.
CMS NPPES provider registry desk
NPI 1639193659 · Psychiatry Physician
NPI-10 · ENUM-LEGACY · TAX-MEGA · RX-MID · BOOK-MID · PHOTO-ENUM
- NPI-10 1639193659
- ENUM-LEGACY 2006
- TAX-MEGA 54K Psychiatry Physician
- RX-MID 2,410
- BOOK-MID 7,890 in California
- PHOTO-ENUM John Tatum, M.D. · 2006
Christopher Dunham, M.D.'s Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2024, across all CMS prescribers nationally
2,410 ≥ 86th percentile 86% of 1,416,883 prescribers are in lower value bands
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.
The percentile is a conservative 100-claim band: it counts only prescribers in lower claim-volume bands. Medicare Part D claim volume is activity context, not a quality measure or recommendation. See methodology § corpus placement.
Source CMS Medicare Part D Prescriber Public Use File · 2024
✓
Board certification likely (heuristic, not verified)
Christopher Dunham, M.D. practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + 1 hospital affiliation - signals consistent with board-certified status. For verified board certification, see CertificationMatters.org (the official ABMS public lookup).
What does the federal data show about Christopher Dunham, M.D.?
Quality data not reportedPrimary specialty
Psychiatry Physician
Medicare Part D claims
2,410 139% vs specialty avg
Specialty distribution in California
How 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 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).
Practice Address
Provider Details
| NPI | 1639193659 |
|---|---|
| Specialty | Psychiatry Physician |
| Credentials | M.D. |
| Gender | Male |
| NPI Issued | 07/26/2006 |
Hospital and facility affiliations
Facilities where Christopher Dunham, M.D. bills Medicare from. Star ratings (1-5) are CMS Hospital Compare's "Hospital overall rating" - a composite of mortality, readmission, patient experience, safety, timely care, and efficient use of medical imaging measures. Source: CMS Care Compare.
County OF Butte
Oroville, CA
Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).
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 Christopher Dunham, M.D.. To verify Christopher Dunham, 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
Christopher Dunham, M.D. - brand share 6.0%
Psychiatry Physician average
6% brand-name claims vs 94% generic, on 2,410 2024 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 2024.
2,410
Total Claims
$450K
Total Drug Cost
96
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 2,553.333
- Total Day Supply
- 73,427
- Brand vs Generic
- 6% brand / 94% generic
- Brand Drug Cost
- $383K
- Generic Drug Cost
- $67K
Patient Demographics
- Average Patient Age
- 55.4 years
- Avg HCC Risk Score
- 1.18
- Gender Split
- 46% female / 54% male
- Age Distribution
- <65: 63, 65-74: 23, 75-84: N/A, 85+: N/A
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2024. Based on Medicare Part D data only.
What Christopher Dunham, M.D. prescribes most
Top Medicare Part D drugs by claim count, 2024
- Olanzapine
Olanzapine
205 claims
- Sertraline Hcl
Sertraline Hcl
135 claims
- Gabapentin
Gabapentin
125 claims
- Risperidone
Risperidone
116 claims
- Benztropine Mesylate
Benztropine Mesylate
111 claims
- Divalproex Sodium
Divalproex Sodium
110 claims
- Quetiapine Fumarate
Quetiapine Fumarate
109 claims
- Trazodone Hcl
Trazodone Hcl
108 claims
| Drug | Claims |
|---|---|
| Olanzapine | 205 |
| Sertraline Hcl | 135 |
| Gabapentin | 125 |
| Risperidone | 116 |
| Benztropine Mesylate | 111 |
| Divalproex Sodium | 110 |
| Quetiapine Fumarate | 109 |
| Trazodone Hcl | 108 |
| Clozapine | 90 |
| Fluoxetine Hcl | 74 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Psychiatry Physician Overview
How Christopher Dunham, M.D. fits within the Psychiatry Physician landscape nationally.
54,383
Psychiatry Physician Providers in US
56
States with Psychiatry Physician
1,010
Avg Claims per Provider
Christopher Dunham, M.D.'s 2,410 claims are above the specialty average of 1,010.
Nationwide Psychiatry Physician peers with similar MIPS or enrollment year
Two federal-record peer sets for Dunham, both outside California so the neighborhoods are not geographic containment.
Same NPPES enumeration year (2006)
Same-specialty clinicians who entered the NPI registry in the same calendar year, outside this state.
Nearby Psychiatry Physician Providers in California
Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as Dunham.
One of 7,890 Psychiatry Physician providers enrolled in California, 5 are shown here.
Dr. Nancy Aaen
MD
Napa, CA
Dr. Criselda Abad-Santos
M.D.
Woodland Hills, CA
Dr. Mekabiz Abaian
MD
San Bernardino, CA
Dr. Kafia Abbasi
M.D.
French Camp, CA
Dr. Michele Abbasi
M.D.
Westlake Village, CA
Compare Psychiatry Physician nationally: see state-by-state distribution →
Frequently Asked Questions
What is Christopher Dunham, M.D.'s specialty? ▼
Christopher Dunham, M.D. specializes in Psychiatry Physician and practices in Chico, California. Credentials: M.D..
How much does Christopher Dunham, M.D. prescribe under Medicare Part D? ▼
In 2024, Christopher Dunham, M.D. wrote 2,410 Medicare Part D claims totaling $450K in drug costs for 96 beneficiaries.
Where is Christopher Dunham, M.D. located? ▼
Christopher Dunham, M.D. is located at 560 COHASSET RD STE 175, Chico, CA, 95926. Phone: (530) 891-2810.
What is Christopher Dunham, M.D.'s NPI number? ▼
Christopher Dunham, M.D.'s National Provider Identifier (NPI) is 1639193659, issued on 07/26/2006.
Does Christopher Dunham, M.D. prescribe more brand-name or generic drugs? ▼
Christopher Dunham, M.D.'s prescribing is 6% brand-name and 94% generic drugs by claim count, with $383K in brand drug costs.
How many Psychiatry Physician providers are there in the US? ▼
There are 54,383 Psychiatry Physician providers across 56 states in the US. The average Psychiatry Physician provider writes 1,010 Medicare Part D claims per year.
What drugs does Christopher Dunham, M.D. prescribe most often? ▼
Based on 2024 Medicare Part D data, Christopher Dunham, M.D.'s most frequently prescribed drugs include Olanzapine, Sertraline Hcl, Gabapentin. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Christopher Dunham, M.D. accept Medicare? ▼
Christopher Dunham, M.D. appears in CMS Medicare data with 2,410 Part D claims and 96 Medicare beneficiaries in 2024. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Christopher Dunham, M.D.'s credentials? ▼
Christopher Dunham, M.D.'s NPI is 1639193659 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 (2024). 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 August 2026 (NPPES) / 2024 (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
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 August 2026.