Mental retardation is a developmental classification, defined as a severe intellectual or cognitive deficit that occurs during development. It is not a disease in itself. Mental retardation can both coexist with other disorders and be caused by other disorders. For this reason, there is no single set of symptoms that suggests mental retardation.
Keeping this in mind, there are behavioral, physical, and medical symptoms that do suggest the presence of mental retardation. In general, mentally retarded children reach developmental milestones such as walking and talking much later than their peers do. Symptoms of mental retardation may appear at birth or later in childhood. Time of onset depends on the suspected cause of the disability. Some cases of mild mental retardation are not diagnosed until the child enters preschool. These children typically have difficulties with social, communication, and functional academic skills. Children who have a neurological disorder or illness such as encephalitis or meningitis may suddenly show signs of cognitive impairment and adaptive difficulties.
Mental retardation is difficult to detect in infancy unless specific physical attributes associated with a syndrome that causes mental retardation are present. Small children who have mental retardation often have developmental delays that result in their inability to meet age-appropriate milestones including sitting up, crawling, walking, and talking.
Physical traits and failure to meet developmental milestones are usually the first symptoms of mental retardation that are noticed. Functional problems, not IQ (which requires testing that does not occur until school age), tend to be the cursors that prompt parents and doctors to test for mental retardation.
Mild retardation is often quite subtle and frequently goes undetected until the child enters the school environment. The educational setting makes demands on the child's intellectual skills and cognitive functioning. Mentally retarded children tend to have difficulty retaining information. The inability to remember things inhibits the child's ability to learn. This becomes readily apparent in a school environment.
Problem solving skills are lacking in mentally retarded individuals, as are deficits in logical thinking and abstract thought. The deficit in abstract thought manifests itself in the child's inability to generalize from one situation to another. Instead of being able to see relationships between similar but different things, mentally retarded children tend to think in a more concrete manner and may be unable to see how things are related.
Deficits in social skills also come into play in a school setting. Individuals who have mental retardation struggle with understanding social rules like taking turns and waiting until someone else finishes speaking before talking. Some social concepts are beyond the grasp of those who are mentally retarded. The concept of money is a good example; mentally retarded individuals tend to have difficulty understanding how money works. Mentally retarded individuals also tend to have difficulty understanding cause and effect relationships, for example, recognizing that there are consequences for actions.
Mental retardation may also be identified when a medical syndrome is identified based on genetic or other medical testing. For example, genetic disorders such Down syndrome can be identified during pregnancy thorough amniocentesis, chorionic villus sampling (CVS), and other techniques used to gather information about fetal chromosomes and genetic make-up. In such cases, the symptoms that point to the presence of a genetic disorder are also symptoms of mental retardation.
