George Gammon, MD
George Gammon, MD is an Addiction Medicine (Psychiatry & Neurology) Physician in Hamden, CT, registered under NPI 1053438267. This provider registers 4 separate taxonomy codes, which usually means they practise across more than one recognised specialty. NPPES records them as a sole proprietor, meaning the practice is not incorporated as a separate legal entity.
Getting there
The practice address on file is 33 EDGEHILL TER, Hamden, CT 06517. We have not yet mapped what surrounds this office — parking, transit, and nearby pharmacies are added as our data collection reaches each location.
Credentials and Medicare
| Licence | State | Specialty |
|---|---|---|
| 020807 | CT | Addiction Medicine (Psychiatry &… primary |
| 020807 | CT | Psychiatry Physician |
| 020807 | CT | Addiction Psychiatry Physician |
| 020807 | CT | Child & Adolescent Psychiatry Physician |
This provider holds licence 020807 issued in CT. A licence number in NPPES reflects what was filed at registration — it does not confirm the licence is still active today.
This NPI does not appear in the PECOS Medicare enrolment file. Providers who do not bill Medicare — or who bill only through a group's enrolment — will not appear here. It is not a sign of any problem with the registration.
What Addiction Medicine covers
A doctor of osteopathy board eligible/certified in the field of Psychiatry by the American Osteopathic Board of Neurology and Psychiatry is able to obtain a Certificate of Added Qualifications in the field of Addiction Medicine NUCC Health Care Provider Taxonomy, code 2084A0401X
All registered taxonomy codes
This provider registers 4 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 2084A0401X | Addiction Medicine (Psychiatry & Neurology) Physician Addiction Medicine | 020807 | CT | primary |
| 2084P0800X | Psychiatry Physician Psychiatry | 020807 | CT | |
| 2084P0802X | Addiction Psychiatry Physician Addiction Psychiatry | 020807 | CT | |
| 2084P0804X | Child & Adolescent Psychiatry Physician Child & Adolescent Psychiatry | 020807 | CT |
The taxonomy records how the provider classifies their own practice. It does not confirm which conditions they currently treat, whether they are accepting new patients, or which insurance they take — call the office for that.
Full NPPES record
An NPI-1 identifies a single person. It stays with the clinician for life, even if they move practice or change state, which is why the address on file can lag behind where they actually work today.
| NPI | 1053438267 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Mar 23, 2007 |
| Last updated | Sep 11, 2025 |
| Status | Active |
| Sole proprietor | Yes |
| Credential | MD |
| Practice address |
33 EDGEHILL TER Hamden, CT 06517 (203) 865-6540 |
Number check
How the check works, step by step
Every NPI carries a Luhn check digit — the same scheme used on credit cards. CMS prefixes the number with 80840 before computing it, which marks it as a US health identifier.
| Digit | 8 | 0 | 8 | 4 | 0 | 1 | 0 | 5 | 3 | 4 | 3 | 8 | 2 | 6 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 0 | 1 | 3 | 8 | 3 | 7 | 2 | 3 |
Sum = 53 · next multiple of 10 = 60 · check digit = 7 · actual last digit = 7
A valid check digit only means the number is well-formed. It does not mean the provider is licensed, active, or in good standing — those are separate questions answered by the sections above.