Daniel Johnson, PhD Clinical Psychologist, Director, Acceptance and Commitment Therapy Program, Boston Child Study Center Dan Johnson, PhD, is a licensed clinical psychologist in Massachusetts. He is an instructor at Harvard Medical School and a staff psychologist in two settings: the West End Clinic at Massachusetts General Hospital and the Boston Child Study Center. His clinical work focuses on acceptance- and mindfulness-based behavioral therapies for psychopathology, including mood disorders, anxiety disorders and substance use disorders in adolescents, young adults and adults.