William Clark, M.D.
NPI 1578574000 · Psychiatry Physician · Chicago, IL
Enrolled with Medicare as Practitioner - Psychiatry · source: CMS PECOS Public Provider Enrollment (2026.04.01)
William Clark, M.D. is a Psychiatry Physician provider in Chicago, IL (NPI 1578574000).
Provider details
- NPI number
- 1578574000
- Entity type
- Individual
- Primary specialty
- Psychiatry PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- No
- License
- 336 040184 (IL)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
19 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)28% of score
946 Medicare services, 2024 (ranked within specialty)
Medicare volume is ranked against active providers in the same specialty. 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 does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 467 | $89 |
| Psychotherapy With Evaluation and Management Visit, 30 Minutes90833 | 265 | $70 |
| Psychotherapy With Evaluation and Management Visit, 45 Minutes90836 | 202 | $88 |
| Psychiatric Diagnostic Evaluation With Medical Services90792 | 12 | $188 |
Typical Medicare-allowed amounts for these services range $70–$188 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, not a price quote and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 26 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Escitalopram Oxalate | 143 | 38 |
| Clonazepam | 110 | 23 |
| Alprazolam | 100 | 15 |
| Bupropion Hclbrand: Bupropion Xl | 83 | 19 |
| Sertraline Hcl | 69 | 15 |
| Dextroamphetamine/Amphetaminebrand: Dextroamphetamine-Amphetamine | 66 | 11 |
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-08-10
- Last updated
- 2010-07-13
Frequently asked questions
- What is William Clark's NPI number?
- William Clark's National Provider Identifier (NPI) is 1578574000, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is William Clark's specialty?
- William Clark is listed in the NPPES registry with a primary specialty of Psychiatry Physician (Allopathic & Osteopathic Physicians).
- Where is William Clark located?
- William Clark's practice location on file with NPPES is 737 N Michigan Ave, Chicago, IL 60611.
- What is William Clark's phone number?
- The practice phone number listed in the NPPES registry for William Clark is (312) 373-7300.
- Does William Clark accept Medicare?
- William Clark is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is William Clark's NPI active?
- Yes — William Clark's NPI (1578574000) is active in the NPPES registry as of the last update on 2010-07-13.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.