People with limited mental abilities struggle to develop the skills needed for independent living. Without these skills, it is hard to live in a safe and socially responsible manner. Children with IDs usually develop more slowly than their peers. They usually sit, walk, and talk much later than other children. This delayed development means they do not act their age.
Limited mental capacity makes learning very difficult. Therefore, learning new information and skills is challenging. As such, learning proceeds more slowly. It is also difficult to apply information in a practical and functional manner. People with ID have trouble grasping complex and abstract concepts. This affects their ability to develop important social skills. This is because social skills are complex and abstract.
IDs can coexist with psychiatric disorders. Some psychiatric conditions, such as autism, can cause ID. There are many other causes of ID. There are many genetic causes. Brain injuries can cause ID. Therefore, no single set of symptoms can completely describe an ID. Nonetheless, it may be useful to discuss some common characteristics.