Temporary Reciprocity to Ensure Access to Treatment Act or the TREAT Act This bill temporarily authorizes the interstate provision of mental health telehealth services during a declared national emergency. Specifically, subject to scope of practice and other requirements, a health care professional may provide mental health services via telehealth in any U.S. jurisdiction based on that individual's authorization to practice in any one state or territory. The bill also provides certain related powers to health care professional regulatory bodies, such as medical boards. Specifically, a regulatory body may investigate and take disciplinary actions against a professional who provides services pursuant to this bill to a patient in that body's jurisdiction.