A general practitioner manages types of illness that present in an undifferentiated way at an early stage of development, which may require urgent intervention. The holistic approach of general practice aims to take into consideration the biological, psychological, and social factors relevant to the care of each patient's illness. Their duties are not confined to specific organs of the body, and they have particular skills in treating people with multiple health issues. They are trained to treat patients of any age and sex to levels of complexity that vary between countries.