The two main types of codes are 1) the general codes that cover the basic professional specialities and that contain provisions relevant to forensic and legal activities and 2) the more specific codes and standards that deal directly with forensic and legal applications in psychiatry and psychology. Most of the roles of psychiatrists and psychologists in the legal and correctional systems relate to communicating scientific, technical, and clinical information to personnel who may have only a limited understanding of the full implications of the information conveyed. Formal codes are important because these codes form the basis of determinations of whether a professional has engaged in unethical conduct. Neither psychiatry nor psychology has produced an ethical code that deals directly and exclusively with forensic or legal activities in the mental health field. The code of the American Academy of Forensic Sciences is the most specific code of ethics concerning forensic activity by mental health professionals. Basic principles of forensic ethics include dignity, impartiality, devotion to justice and truth, resistance to pressures to compromise ethical standards, and avoidance of excessive publicity or releasing data or results improperly. Charts and 85 references.