The term "mentally handicapped" is often used interchangeably with "mental retardation," "developmentally disabled" or "mentally challenged." The Genetics Home Reference defines a mental handicap or mental retardation as "subnormal intellectual functioning which originates during the developmental period" or a "subaverage intellectual ability that is equivalent to or less than an IQ of 70." In layman's terms, this term refers to people with less-than-average intelligence and often behavioral or social problems. Mental handicaps are most often diagnosed in childhood.
Causes
Mental handicaps have multiple potential causes. Some infections that are present at birth or that happen soon after can cause mental handicaps, including congenital rubella, meningitis, encephalitis, HIV or cytomegalovirus, also known as CMV. Chromosomal abnormalities before birth such as deletions, a gene not located in the normal spot or an error in the number of chromosomes can cause mental handicaps. Genetic diseases--those that are inherited through the parents--also can cause mental handicaps. Lead or mercury exposure and the use of drugs or alcohol during pregnancy are causes as well.
Identification
A mental handicap may be hard to identify early in a child, because how it is presented may depend on the cause. Children with a mental handicap may continue infantile behavior longer than is considered normal. There may be developmental delays in the growing process and a failure to meet intellectual development milestones. Some children with a mental handicap do not exhibit the curiosity typical of their age group. Once a mentally handicapped child reaches school age, he normally exhibits poor performance on problem-solving, short-term memory and learning tasks. Learning ability, as well as daily living skills, communication skills and social skills, are evaluated to diagnose a mental handicap.
Levels
The average IQ for someone without a mental handicap is 100. An IQ in the 50 to 70 range is considered a mild mental handicap; an IQ in the 35 to 49 range is considered a moderate handicap; an IQ in the 20 to 34 range is considered a severe handicap and an IQ of less than 20 is a profound handicap. A person identified with a mild mental handicap normally can learn basic skills in school and daily living. A moderate to severe mental handicap normally means the ability to learn basic social, communication and self-help skills is still present, but acquiring these skills may be more difficult, and behavior problems may be more likely. Someone with a profound mental handicap may have the ability to learn basic self-help skills but will require constant supervision and care throughout life.
Prevalence
Statistics vary, but research in the U.S. and U.K. indicates that mental handicaps affect between 1 and 3 percent of the population. Of this percentage, doctors normally find a cause for the handicap in only about 25 percent of the cases. A study of school-age children in special education classes found that 1 in 10 had a mental handicap. People with mental handicaps may also have cerebral palsy and motor skill problems, seizure disorders, visual or hearing difficulties or behavioral problems.
Considerations
Each person with a mental handicap may exhibit the symptoms and complications differently. Behavioral issues include acting out, being overly impulsive, harming oneself or being unable to interact with others appropriately. Having a family member with a profound mental handicap affects the whole family, as life-long care is necessary and feelings of isolation may increase.
