David Hessl, PhD, is a clinical professor in the Department of Psychiatry and Behavioral Sciences at the University of California, Davis, where he is on the faculty of the MIND Institute. He is a licensed clinical psychologist and the head psychologist at the Fragile X Research and Treatment Center at UC Davis, where FXTAS (Fragile X-associated tremor/ataxia syndrome) was first discovered and reported in 2001.

Dr. Hessl is director of the Translational Psychophysiology and Assessment Laboratory (T-PAL) at the MIND Institute. T-PAL is primarily devoted to developing novel outcome measures for clinical trials of individuals with neurodevelopmental disorders.

Dr. Hessl’s career has focused on Fragile X-associated disorders since 1998, having published 114 peer-reviewed journal articles on these topics to date. He is a lead investigator of a research program supported by the National Institute of Neurological Diseases and Stroke, focused on neuropsychological and neurological changes in Fragile X premutation carriers to determine key risk factors and early signs of neurodegeneration related to FXTAS. This work has also uncovered genetic and brain mechanisms contributing to mental health challenges in premutation carriers, supported by the National Institute of Mental Health. Dr. Hessl serves on the National Fragile X Foundation’s Clinical Trials and Scientific & Clinical Advisory Board committees.