DeMaria is a clinical psychologist who provides individual and couples therapy. His work focuses on psychotherapy for relationship conflict, stress, specific life problems, and acute symptoms, with an emphasis on improving overall quality of life through greater insight, skills, and awareness. He has authored peer-reviewed publications on evidence-based therapy practices, psychotherapy training, and improving doctor-patient relationships, and has served as a supervising psychologist and clinical professor of psychiatry. His clinical training includes NYU-Bellevue Hospital Center, Beth Israel Medical Center, and other New York City hospitals, and he has presented on the treatment of personality disorders at conferences and hospital grand rounds.