What are the causes and symptoms of mental retardation?
Low IQ scores and limitations in adaptive skills are the hallmarks of mental retardation. Aggression, self-injury, and mood disorders are sometimes associated with the disability. The severity of the symptoms and the age at which they first appear depend on the cause. Children who are mentally retarded reach developmental milestones significantly later than expected, if at all. If retardation is caused by chromosomal or other genetic disorders, it is often apparent from infancy. If retardation is caused by childhood illnesses or injuries, learning and adaptive skills that were once easy may suddenly become difficult or impossible to master. In about 35% of cases, the cause of mental retardation cannot be found. Biological and environmental factors that can cause mental retardation include: Source: The Gale Group. Gale Encyclopedia of Medicine, 3rd ed.
