Mark A. Williamson, MD
Psychiatry Physician · Houston, TX
Mark A. Williamson, MD is a psychiatry physician with a practice address in Houston, Texas, and NPI 1760591028, issued on Aug 30, 2006. Check the license (Texas H4855, as entered in NPPES) on the Texas Medical Board; the Medicare figures below come from public CMS files.
- Name
- Mark A. Williamson
- Credential
- MD
- Primary taxonomy
- Psychiatry Physician 2084P0800X
- License number
- H4855 TX
Self-reported in NPPES; status is on the state search - Practice location
- 5901 Long Dr, Houston, TX 77087
- Phone
- (713) 970-7000
- Enumerated
- Aug 30, 2006
- Record last updated
- Jan 29, 2019 (not updated in 7 years: call before relying on the address or phone)
- Fax
- (713) 970-7246
- Medicare enrollment
- Enrolled (PECOS I20071128000418); may accept Medicare assignment
- Medical or professional school
- University Of Texas Medical Branch At Galveston, 1984
- Entity
- Type 1 · individual
8 nearest psychiatry physician records → All 3,318 in Texas → Look up another NPI →
Also registered at 5901 Long Dr
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Nora Bailey, M.D.Psychiatry Physician1699191908
- Heather Barr, LCSWClinical Social Worker1184364879
- Jerry Branch, LCDCAddiction (Substance Use Disorder) Counselor1689566580
- Markus Carter, LCSWClinical Social Worker1932917242
- Valerie Chapa, LCSWClinical Social Worker1316338262
Verify Mark A. Williamson in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersTexas Medical Board
Search for license H4855Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
43% fewer Medicare Part D claims than the average psychiatry physician in 2024
572 Medicare Part D claims for 33 beneficiaries, against an average of 1,000 among the 35,054 providers of this specialty who prescribed in Part D. Brand-name drugs were 11% of claims.
Most prescribed
- Benztropine Mesylate78 claims
- Divalproex Sodium Er58 claims
- Lithium Carbonate Er52 claims
- Olanzapine50 claims
- Invega Sustenna30 claims
- Risperidone29 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.
The practice group's MIPS final score for 2023 (Medicare payment program): 85.7 of 100
The Merit-based Incentive Payment System score is reported for the practice group, not for one clinician alone. Four categories are weighted into the final score; the average among 454,083 clinicians with a measured score was 83.5.
Source: CMS Quality Payment Program, MIPS performance year 2023, group reporting; category weights for 2023 (qpp.cms.gov).
Industry payments in 2024: $269.99
2 payments; by number, the most common kind was food and beverage; the largest payer was Janssen Pharmaceuticals, Inc. The 13,693 providers of this specialty with any payment received $4,954.93 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Mark A. Williamson among 3,318 psychiatry physician records in Texas
Mark A. Williamson, MD is one of 3,318 psychiatry physician records with a practice address in Texas. 72% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 5% of them.
- NPI issued2006 · 5% of these records are older, 65% newer
- In a Medicare fileYes · 72% of these records are
- In the CMS Doctors and Clinicians fileYes · 45% of these records are
- Graduated1984 · median 2006 among the 1,481 with a school on file
- Record last updated2019 · 49% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 2084P0800X and a Texas practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Psychiatry Physician providers in Texas
There are 3,318 psychiatry physician records in Texas.
All 3,318 in Texas → Every provider in Houston → Psychiatry Physician nationwide →
The 8 psychiatry physician records with the nearest ZIP codes
- Nora Bailey, M.D.Houston, TX 770871699191908
- Amol Chaugule, M.D.Houston, TX 770871417187527
- Woodrow Coppedge, M.D.Houston, TX 770871952356321
- Faye SadberryHouston, TX 770871255441895
- Christina Williams, M.D.Houston, TX 770871396159679
- Larry Flowers, M.D.Houston, TX 770901750336707
- Madiha Ghayas, M.D.Houston, TX 770841609199926
- Lawrence Ginsberg, M.D.Houston, TX 770901851385835
Common questions
What is Mark A. Williamson, MD's NPI number?
Mark A. Williamson, MD's National Provider Identifier (NPI) is 1760591028, issued on Aug 30, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Mark A. Williamson, MD located?
The NPPES record lists a practice address at 5901 Long Dr, Houston, TX, 77087. Phone: (713) 970-7000. Providers update this record themselves, so call before visiting.
How can I verify Mark A. Williamson, MD's license?
NPPES lists Texas license number H4855, as entered by the provider. Search the Texas Medical Board at https://profile.tmb.state.tx.us/Search.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Mark A. Williamson, MD prescribe under Medicare Part D?
In 2024, Mark A. Williamson, MD had 572 Medicare Part D claims for 33 beneficiaries; the average among psychiatry physician prescribers was 1,000. Part D covers Medicare prescriptions only.
What is Mark A. Williamson, MD's MIPS final score?
The 2023 MIPS final score is 85.7 of 100, reported for the practice group. The average among 454,083 clinicians with a measured score was 83.5.
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.