Mental Retardation Definition

Whenever a kid has subpar intellectual functioning and deficiencies in adaptive skill areas such as personality, interaction, household dwelling and public usage, interpersonal and consciousness, self-direction, health and safety, effective education, recreation, and employment, this is referred to as mental retardation. When a child’s eyes, speech, and limbs appear normal yet he behaves inappropriately for his age, it might cause misunderstanding and false beliefs about his handicap.

Classification of Mental Retardation

In accordance with IQ levels, the American Association on Mental Retardation (AAMR) has divided mental retardation (MR) into four categories: (1) mild (IQ 50–70), moderate (IQ 35–40), severe (20–40), and profound (below 20).

Characteristics of Mental Retardation Child

Absence of sufficient motherhood and parenting skills throughout the early years retards a child’s pace of growth. Whenever a child’s possibilities at birth are normal, serious environmental insufficiency in the form of physical, emotional, social, and intellectual poverty during infancy and childhood causes the child’s intellectual development to be delayed. Educational disorganization also has a tendency to slow the growth of the individual.

Causes of Mental Retardation in Child

Mental retardation is caused by a variety of different circumstances. Prenatal, perinatal, and postnatal are the three phases that might cause mental retardation.

  • Prenatal stage: One encounters a variety of the illnesses listed below in this.

Chromosomal disorders:

Mental retardation can be caused by any anomaly, either in the form or number of chromosomes. Down’s syndrome, a genetic condition, is a common kind of mental impairment. During cell division, a portion of chromosome 21 attaches to another chromosome, frequently number 14, at the time of conception. The number of chromosome 21 in the reproductive cells is normal or balanced if the resultant sperm or ovum receives a chromosome 14 (or another chromosome) with a portion of chromosome 21 attached and keeps the chromosome 21 that lost a part due to translocation. It isn’t “autosomal” or “other,” it’s just a mistake in Chromosome 21’s translation (three copies instead of two).

Trisomy 13, and Trisomy 18, which are attributed to the presence of three chromosomes rather than two, and fragile X syndrome, in which the tip of the X chromosome falls off, are other abnormalities connected to MR.

Genetic disorder:

Mental retardation may be caused by a genetic flaw passed down from parents to children. Unless the problem does not run in the family, several disorders that cause mental retardation may be inherited by the kids. Phenylketonuria, a metabolic condition connected to MR, is brought on by the transmission of two genetic mutations, one from each parent.


If a woman has rubella (German measles) or herpes while pregnant, particularly during the first 3 months, the fetus’s maturing brain may be harmed.

Maternal diseases:

Children who inherit the mother’s illnesses, such as syphilis, etc., may grow up with mental retardation. Additionally, iodine excess or shortage in the mother’s deficiency can lead to MR and other disorders, including cretinism and central nervous system defects.

Exposure to X-rays:

Initially during early pregnancy, dangerous medications, particularly those used to fight cancer, some epileptic medications, and hormonal medications, if used by the mother, can harm the developing fetus.

  • Perinatal stage:

Childbirth traumas such as forceps birth, low birth weight (less than 2 kg), anoxia (lack of oxygen) shortly after birth, and preterm delivery (born between 28 and 34 weeks) have had an elevated risk of mental health impairment.

  • Postnatal stage: 

A child’s recurrent convulsions, malnutrition throughout the first 2 years of life, endocrine illnesses such as meningitis or encephalitis (brain infection), and head injuries can all cause MR.