Dr. Nissen maintains a private practice on Long Island. He also serves as a staff psychologist at both Northwell Health’s Unified Behavioral Health Center for Military Veterans and Families and the FINEST Care Program for police officers. Dr. Nissen has contributed to peer-reviewed publications and presentations on topics including PTSD development, learning styles, clinical technique, the unconscious mind, and hypnosis. His research is largely focused on personality, unconscious processing, trauma, and political opinion forming. He is an active member of several professional organizations, including the New York State Psychological Association (Division of Psychoanalysis), the Suffolk County Psychological Association, and the New York State Troopers PBA Surgeons Group. In both clinical and academic roles, Dr. Nissen integrates an evidence-based psychodynamic and psychoanalytically-informed approach with cognitive, behavioral, and motivational interviewing perspectives to support healing, insight, and resilience in individuals experiencing emotional challenges.
