John Hassler, M.D.
NPI 1306928700 · Psychiatry Physician · La Jolla, CA
Enrolled with Medicare as Order and Referring Only - Psychiatry · source: CMS PECOS Public Provider Enrollment (2026.04.01)
John Hassler, M.D. is a Psychiatry Physician provider in La Jolla, CA (NPI 1306928700).
Provider details
- NPI number
- 1306928700
- Entity type
- Individual
- Primary specialty
- Psychiatry PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- G15132 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
19 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
1 documented practice location
Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 8 distinct drugs on file.
| Drug | Part D claims (2024) |
|---|---|
| Lorazepam | 35 |
| Clonazepam | 24 |
| Bupropion Hclbrand: Bupropion Xl | 22 |
| Aripiprazole | 15 |
| Dextroamphetamine/Amphetaminebrand: Dextroamphetamine-Amphetamine | 13 |
| Alprazolam | 12 |
| Duloxetine Hcl | 11 |
| Vortioxetine Hydrobromidebrand: Trintellix | 11 |
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-10-19
- Last updated
- 2007-07-08
Frequently asked questions
- What is John Hassler's NPI number?
- John Hassler's National Provider Identifier (NPI) is 1306928700, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is John Hassler's specialty?
- John Hassler is listed in the NPPES registry with a primary specialty of Psychiatry Physician (Allopathic & Osteopathic Physicians).
- Where is John Hassler located?
- John Hassler's practice location on file with NPPES is 1223 Roslyn Ln, La Jolla, CA 92037-3648.
- What is John Hassler's phone number?
- The practice phone number listed in the NPPES registry for John Hassler is (858) 454-9341.
- Does John Hassler accept Medicare?
- John Hassler is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is John Hassler's NPI active?
- Yes — John Hassler's NPI (1306928700) is active in the NPPES registry as of the last update on 2007-07-08.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.