John P. Shallcross, PsyD

Licensed Clinical Psychologist located in Marietta, GA & Roswell/Alpharetta, Roswell, GA

About John P. Shallcross, Psy.D.


Dr. Shallcross is a licensed clinical psychologist. He has been practicing psychology since 1987.


He received his doctoral degree at the University of Hartford in Connecticut. He received a Master’s degree from Yale University. Dr Shallcross currently specializes in psychological testing, evaluation, and diagnosis of ADHD, as well as personality assessment, differential diagnosis, and neuropsychological screening. He has extensive experience in working with child, adolescent, and adult clients. Dr. Shallcross performs diagnostic psychological testing and neuropsychological screening at area psychiatric hospitals (Ridgeview Institute, Peachford, and Anchor) and receives referrals from prominent Atlanta area psychiatrists, psychologists, and other physicians for diagnostic testing and assistance in medication management and treatment planning.

ADHD Testing:

An appointment with Dr. Shallcross consists of a single visit appointment with clinical interview and testing for the assessment and diagnosis of ADHD. The testing measures working memory, immediate auditory attention, vigilance, speed for visual search, and mental flexibility. As ADHD is a diagnosis of exclusion, one or two additional hours may be required for evaluation of any concomitant mood/psychiatric disorders (ages 9-adult) and screening for learning disorders (ages 7-12).