Troy Ewing, Psy.D. Dr. Ewing is a licensed clinical psychologist and CEO of Ewing Diagnostics & Psychological Services, Inc. He has worked for the University of California Davis, California State University Sacramento, Metropolitan State College of Denver, and for the California Department of Corrections and Rehabilitations. Presently, Dr Ewing resides in Northern California with his wife, practices full time in one of his five private practice office locations, and is completing a series of books on current mental health topics.