Warren Ritchie Christianson, D.O.
Psychiatry Physician · San Marino, CA
Warren Ritchie Christianson, D.O. is a psychiatry physician with a practice address in San Marino, California, and NPI 1932359445, issued on Sep 22, 2008. Check the license (California 20A9664, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Warren Ritchie Christianson
- Credential
- D.O.
- Primary taxonomy
- Psychiatry Physician 2084P0800X
- License number
- 20A9664 CA
Self-reported in NPPES; status is on the state search - Practice location
- 2400 Mission St, San Marino, CA 91108
- Phone
- (626) 403-8999
- Enumerated
- Sep 22, 2008
- Record last updated
- Sep 21, 2011 (not updated in 15 years: call before relying on the address or phone)
- Fax
- (626) 403-8989
- Medicare enrollment
- Enrolled (PECOS I20110914000671); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest psychiatry physician records → All 8,673 in California → Look up another NPI →
Also registered at 2400 Mission St
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Terry Bissell, M.D.Psychiatry Physician1053449934
- Ryan Courdy, M.D.Psychiatry Physician1265507644
- Daniel Doyle, M.F.T.Marriage & Family Therapist1730218264
- Camille Fagenson, L.C.S.W.Clinical Social Worker1689702466
- Karen Gates, L.C.S.W.Clinical Social Worker1013045897
- Iris Haas-BielMarriage & Family Therapist1588427389
Verify Warren Ritchie Christianson in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license 20A9664Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
87% fewer Medicare Part D claims than the average psychiatry physician in 2024
128 Medicare Part D claims for 17 beneficiaries, against an average of 1,000 among the 35,054 providers of this specialty who prescribed in Part D.
Most prescribed
- Gabapentin21 claims
- Buprenorphine-Naloxone14 claims
- Armodafinil11 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: $25.63
1 payment: food and beverage; the largest payer was Axsome Therapeutics, 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.
Bills Medicare through 2 group practices
- San Marino Psychiatric Associates IncSan Marino, CA
- Vista Community ClinicVista, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Warren Ritchie Christianson among 8,673 psychiatry physician records in California
Warren Ritchie Christianson, D.O. 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 2008, is newer than 52% of them.
- NPI issued2008 · 52% of these records are older, 43% newer
- In a Medicare fileYes · 67% of these records are
- In the CMS Doctors and Clinicians fileYes · 38% of these records are
- Graduated2004 · median 2005 among the 3,295 with a school on file
- Record last updated2011 · 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).
8 psychiatry physician records list a practice address in San Marino
They are 8 of the 184 NPPES records with a practice address in San Marino, and 8,673 psychiatry physician records in California.
All 8,673 in California → Every provider in San Marino → Psychiatry Physician nationwide →
The 8 psychiatry physician records with the nearest ZIP codes
- Terry Bissell, M.D.San Marino, CA 911081053449934
- Ryan Courdy, M.D.San Marino, CA 911081265507644
- Sheela Gade, MDSan Marino, CA 911081114143757
- Berry McCord, M.D.San Marino, CA 911081417999418
- Rebecca Najera, DOSan Marino, CA 911081477993889
- Timothy Pylko, M.D.San Marino, CA 911081841328705
- Daniel Suzuki, M.D.San Marino, CA 911081811025679
- Mir Ali-Khan, M.D.,Pasadena, CA 911071780608638
Common questions
What is Warren Ritchie Christianson, D.O.'s NPI number?
Warren Ritchie Christianson, D.O.'s National Provider Identifier (NPI) is 1932359445, issued on Sep 22, 2008. An NPI identifies a provider in billing; it is not a license.
Where is Warren Ritchie Christianson, D.O. located?
The NPPES record lists a practice address at 2400 Mission St, San Marino, CA, 91108. Phone: (626) 403-8999. Providers update this record themselves, so call before visiting.
How can I verify Warren Ritchie Christianson, D.O.'s license?
NPPES lists California license number 20A9664, 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 Warren Ritchie Christianson, D.O. prescribe under Medicare Part D?
In 2024, Warren Ritchie Christianson, D.O. had 128 Medicare Part D claims for 17 beneficiaries; 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.