Why is the truthfulness of a subject not a concern in clinical psychology, but an actual concern in forensic psychology?

A field of psychology that deals with all aspects of human behavior as it relates to the law or legal systems. a debate centers on whether the definition should be broad or narrow. a narrow def. might focus on clinical aspects and ignore conducted experimental research. In 2001 the American Psychological Organization reorganized forensic psychology narrowly as a specialization. Otto and Heilburn state, "it should include the primarily clinical aspects of forensic assessment, treatment and consultation.