The emergence of occupational therapy challenged the views of mainstream scientific medicine. Instead of focusing purely on the medical model, occupational therapists argued that a complex combination of social, economic, and biological reasons cause dysfunction. Principles and techniques were borrowed from many disciplines—including but not limited to physical therapy, nursing, psychiatry, rehabilitation, self-help, orthopedics, and social work—to enrich the profession's scope. Between 1900 and 1930, the founders defined the realm of practice and developed supporting theories. By the early 1930s, AOTA had established educational guidelines and accreditation procedures.