David Hessl, Ph.D.

David Randal Hessl, Ph.D.


Child Clinical Psychology



  • Clinical Professor


To see if David Randal Hessl is accepting new patients, or for assistance finding a UC Davis doctor, please call 800-2-UCDAVIS (800-282-3284).

UC Davis MIND Institute

2825 50th St.
Sacramento, CA 95817
Driving Directions

Primary Phone:

Additional Phone Numbers

Clinic Phone: 916-703-0308
Physician Referrals: 800-4-UCDAVIS (800-482-3284)



Philosophy of Care

My philosophy is first to be a good listener, to really appreciate the patient's perspective, their developmental background, and to approach children and those with disabilities at their level.  I enjoy using humor and a casual style to connect with these patients.  I always try to bring knowledge of disabilities through scientific inquiry into the assessment process.

Clinical Interests

Dr. Hessl is a licensed clinical psychologist with clinical interests involve cognitive, emotional, and behavioral evaluation of children, adolescents and adults with neurodevelopmental disorders, especially those with fragile X syndrome, Down syndrome, autism spectrum disorders, ADHD, Tourette Disorder and learning disabilities. 

Research/Academic Interests

Dr. Hessl directs the Translational Psychophysiology and Assessment Laboratory (T-PAL) at the MIND Institute to investigate the emotional psychophysiology of children with neurodevelopmental disorders, and to develop novel outcome measures for clinical trials. 

He also conducts collaborative studies with other researchers, investigating brain imaging, molecular genetics and neuropsychology in an effort to understand links between genetics, brain function and behavior.  His research focus is primarily on fragile X-associated disorders, such as fragile X syndrome and fragile X-associated tremor ataxia syndrome (FXTAS).  His lab has contributed to the refinement or development of cognitive and behavioral assessments for people with disabilities.



Center/Program Affiliation

UC Davis MIND Institute


Ph.D., Child Clinical Psychology and Developmental Psychology, University of Washington, Seattle WA 1997

M.S., Child Clinical Psychology, University of Washington, Seattle WA 1995

B.A., UCLA, Los Angeles CA 1989

Internship: Lucile Packard Children's Hospital/Children's Health Council, Stanford University School of Medicine, Stanford CA 1996-1997


University of California, Berkeley, Berkeley CA 1997-1998

Board Certifications

Psychologist, 2000

Professional Memberships

American Psychological Association

International Society for Autism Research

Honors and Awards

The John Merck Fun's Developmental Disabilities Translational Research Program Scholar, 2012

Jarrett Cole Clinical Award, National Fragile X Foundation, for �Dedicated Service to Families in the Worldwide Fragile X Community�, 2012

Dean�s Team Award for Excellence, U.C. Davis School of Medicine, 2009

U.C. Davis finalist � John Merck Scholars Program, Biology of Developmental Disabilities in Children, 2008

U.C. Davis Academic Senate Research Travel Award, 2008

MIND Institute Pilot Research Grant Award, 2007

U.C. Davis Imaging Research Center Award, 2006

Select Recent Publications

Greiss Hess L, Fitzpatrick SE, Nguyen DV, Chen Y, Gaul KN, Schneider A, Lemons Chitwood K, Eldeeb MA, Polussa J, Hessl D, Rivera S, Hagerman RJ. A Randomized, Double-Blind, Placebo-Controlled Trial of Low-Dose Sertraline in Young Children With Fragile X Syndrome. J Dev Behav Pediatr. 2016 Oct;37(8):619-28.

Hessl D, Sansone SM, Berry-Kravis E, Riley K, Widaman KF, Abbeduto L, Schneider A, Coleman J, Oaklander D, Rhodes KC, Gershon RC. The NIH Toolbox Cognitive Battery for intellectual disabilities: three preliminary studies and future directions. J Neurodev Disord. 2016 Sep 6;8(1):35.

Lozano R, Saito N, Reed D, Eldeeb M, Schneider A, Hessl D, Tassone F, Beckett  L, Hagerman R. Aging in Fragile X Premutation Carriers. Cerebellum. 2016 Oct;15(5):587-94.

Gossett A, Sansone S, Schneider A, Johnston C, Hagerman R, Tassone F, Rivera SM, Seritan AL, Hessl D. Psychiatric disorders among women with the fragile X premutation without children affected by fragile X syndrome. Am J Med Genet B Neuropsychiatr Genet. 2016 Dec;171(8):1139-1147.

Schneider A, Johnston C, Tassone F, Sansone S, Hagerman RJ, Ferrer E, Rivera SM, Hessl D. Broad autism spectrum and obsessive-compulsive symptoms in adults with the fragile X premutation. Clin Neuropsychol. 2016 Aug;30(6):929-43.

Wang JY, Ngo MM, Hessl D, Hagerman RJ, Rivera SM. Robust Machine Learning-Based Correction on Automatic Segmentation of the Cerebellum and Brainstem. PLoS One. 2016 May 23;11(5):e0156123.

Cordeiro L, Abucayan F, Hagerman R, Tassone F, Hessl D. Anxiety disorders in fragile X premutation carriers: Preliminary characterization of probands and non-probands. Intractable Rare Dis Res. 2015 Aug;4(3):123-30.

Au J, Berkowitz-Sutherland L, Schneider A, Schweitzer JB, Hessl D, Hagerman R. A feasibility trial of Cogmed working memory training in fragile X syndrome. J Pediatr Genet. 2014 Sep;3(3):147-56.

Sansone SM, Schneider A, Bickel E, Berry-Kravis E, Prescott C, Hessl D. Improving IQ measurement in intellectual disabilities using true deviation from population norms. J Neurodev Disord. 2014;6(1):16.

Hessl D, Grigsby J. Fragile X-associated tremor/ataxia syndrome: another phenotype of the fragile X gene. Clin Neuropsychol. 2016 Aug;30(6):810-4. doi: 10.1080/13854046.2016.1186661. Epub 2016 Jun 29.