NPI age
19 years
Enumerated 2006-12-13
● Active
Type 1 · Individual
William O Thomason, PH.D
Thomason is 1 of 1 psychologist providers in Terrell and 1 of 24 in Texas.
Primary specialty
Psychologist
Plus 2 subspecialties
Licensed in
TX
1 state
Status
Active
No deactivations on record
Last NPPES update
2025-09-11
Source: monthly bulk 2026-05
Sole proprietor
No
May be part of a larger org
How this provider compares
Across 24 active psychologist providers in Texas.
NPI age
19 years
↑ 2 yr above median (17 yr)
State licenses
1 state
4% of peers hold multiple states
Subspecialties
2
In the 66% of peers with subspecialties
NPI lifetime · 2006 → 2026
2006-12Enumerated in NPPES
2006
2026
Where they practice
Practice location
1200 E Brin St
Terrell, TX 75160
Mailing address
Po Box 70
Terrell, TX 75160
Specialties
-
Psychologist PrimaryA psychologist whose specialty is founded on principles of systems theory with the interpersonal system of the family the focus of assessment, intervention and research.
-
PsychologistA psychologist with a proficiency that involves the application of psychological treatment of addiction stemming from the use of alcohol and other psychoactive substances (e.g., nicotine, marijuana, cocaine, heroin) or behavioral...
-
PsychologistA psychologist who provides continuing and comprehensive mental and behavioral health care for individuals and families; consultation to agencies and communities; training, education and supervision; and research-based practice. It is a...
Practice context
Part of a multi-provider practice. 22 other active providers share this practice address in NPPES.
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