John Gregory Duffy, MD
Psychiatry Physician · Santa Ana, CA
John Gregory Duffy, MD is a psychiatry physician with a practice address in Santa Ana, California, and NPI 1255497251, issued on Dec 28, 2006. Check the license (California A54948, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- John Gregory Duffy
- Credential
- MD
- Primary taxonomy
- Psychiatry Physician 2084P0800X
- License number
- A54948 CA
Self-reported in NPPES; status is on the state search - Practice location
- 1401 N. Tustin Avenue, Suite 130, Santa Ana, CA 92705
- Phone
- (714) 542-3008
- Enumerated
- Dec 28, 2006
- Record last updated
- Mar 15, 2023
- Fax
- (714) 542-3617
- Entity
- Type 1 · individual
8 nearest psychiatry physician records → All 8,673 in California → Look up another NPI →
Verify John Gregory Duffy in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A54948Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
89% fewer Medicare Part D claims than the average psychiatry physician in 2024
107 Medicare Part D claims, against an average of 1,000 among the 35,054 providers of this specialty who prescribed in Part D.
Most prescribed
- Bupropion Xl19 claims
- Divalproex Sodium Er18 claims
- Escitalopram Oxalate12 claims
- Quetiapine Fumarate12 claims
- Memantine Hcl Er11 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.
Industry payments in 2024: $2,225.00
2 payments; by number, the most common kind was food and beverage; the largest payer was Eli Lilly and Company. 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.
John Gregory Duffy among 8,673 psychiatry physician records in California
John Gregory Duffy, MD is one of 8,673 psychiatry physician records with a practice address in California. 67% 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 2% of them.
- NPI issued2006 · 2% of these records are older, 67% newer
- In a Medicare fileYes · 67% of these records are
- In the CMS Doctors and Clinicians fileNo · 38% of these records are
- Record last updated2023 · 54% 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 California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Psychiatry Physician providers in California
There are 8,673 psychiatry physician records in California.
All 8,673 in California → Every provider in Santa Ana → Psychiatry Physician nationwide →
The 8 psychiatry physician records with the nearest ZIP codes
- Serge Abdishoo, M.D.Santa Ana, CA 927051336162759
- Emad Aziz, MDSanta Ana, CA 927051255383030
- Katalin Bassett, MDSanta Ana, CA 927051205964129
- Priti Bhardwaj, M.D.Santa Ana, CA 927051750419230
- Ted Greenzang, MDSanta Ana, CA 927051629133780
- Thomas Okamoto, M.D.Santa Ana, CA 927051235178021
- Santi Pattara, M.D.Santa Ana, CA 927051982796165
- Geoffrey Phillips, M.D.Santa Ana, CA 927051396745501
Common questions
What is John Gregory Duffy, MD's NPI number?
John Gregory Duffy, MD's National Provider Identifier (NPI) is 1255497251, issued on Dec 28, 2006. An NPI identifies a provider in billing; it is not a license.
Where is John Gregory Duffy, MD located?
The NPPES record lists a practice address at 1401 N. Tustin Avenue, Suite 130, Santa Ana, CA, 92705. Phone: (714) 542-3008. Providers update this record themselves, so call before visiting.
How can I verify John Gregory Duffy, MD's license?
NPPES lists California license number A54948, 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 John Gregory Duffy, MD prescribe under Medicare Part D?
In 2024, John Gregory Duffy, MD had 107 Medicare Part D claims; the average among psychiatry physician prescribers was 1,000. 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.