The answer is childhood and poor adaptive behaviors.
Intellectual disability is a state which individual is incapable to adapt things surrounded him or her. Everyone who was eligible for a diagnosis of mental slow development and progress is entitled and qualified for a diagnosis of intellectual disability. Individuals having intellectual disability shows random sheer incompetence, poor understanding, poor adaptation in behaviors of real-life skills such as cleaning, grooming, or avoiding danger, the ability to work, take personal responsibility, and social skills.