William Regan, M.D.
William Regan, M.D. is a Psychiatry Physician in Nashville, TN, registered under NPI 1164576955.
Getting there
The practice address on file is 221 STEWARTS FERRY PIKE, Nashville, TN 37214. 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 |
|---|---|---|
| MD0000014753 | TN | Psychiatry Physician primary |
| 036177893 | IL | Psychiatry Physician |
| 2025019372 | MO | Psychiatry Physician |
Licences are recorded in 3 states: TN, IL, MO. Providers licensed in several states often practise near a state border or deliver telehealth across state lines.
- Status
- Approved
- Provider type
- Practitioner - Psychiatry
- PAC ID
- 2860584638
Medicare enrolment is recorded as approved under the provider type Practitioner - Psychiatry. This means the provider is enrolled to bill Medicare, though it does not tell you whether they are currently accepting new Medicare patients. Call the office to confirm.
Licensed in 3 states
This provider holds licences in 3 states: Illinois, Missouri and Tennessee. The practice address on file is in Nashville, TN, but a licence in another state usually means they see patients there too — either at a second location or by telehealth. If the address above is far from you, it is worth calling to ask whether they practise closer to where you live.
- Licence
- MD0000014753
- Specialty
- Psychiatry Physician
Licence numbers are self-reported to NPPES at registration. They do not confirm a licence is currently active, in good standing, or valid for the specialty shown — only the state board can tell you that, which is why we link to each one.
What Psychiatry covers
A Psychiatrist specializes in the prevention, diagnosis, and treatment of mental disorders, emotional disorders, psychotic disorders, mood disorders, anxiety disorders, substance-related disorders, sexual and gender identity disorders and adjustment disorders. Biologic, psychological, and social components of illnesses are explored and understood in treatment of the whole person. Tools used may include diagnostic laboratory tests, prescribed medications, evaluation and treatment of psychological and interpersonal problems with individuals and families, and intervention for coping with stress, crises, and other problems. NUCC Health Care Provider Taxonomy, code 2084P0800X
All registered taxonomy codes
This provider registers 3 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 2084P0800X | Psychiatry Physician Psychiatry | MD0000014753 | TN | primary |
| 2084P0800X | Psychiatry Physician Psychiatry | 036177893 | IL | |
| 2084P0800X | Psychiatry Physician Psychiatry | 2025019372 | MO |
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 | 1164576955 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Jan 22, 2007 |
| Last updated | Feb 25, 2026 |
| Status | Active |
| Sole proprietor | No |
| Credential | M.D. |
| Practice address |
221 STEWARTS FERRY PIKE Nashville, TN 37214 (615) 902-7461 |
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 | 1 | 6 | 4 | 5 | 7 | 6 | 9 | 5 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 1 | 3 | 4 | 1 | 7 | 3 | 9 | 1 |
Sum = 55 · next multiple of 10 = 60 · check digit = 5 · actual last digit = 5
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.