Understanding Psychology (10th Ed)

 IDENTIFYING THE ROOTS OF MENTAL RETARDATION 
What produces mental retardation? In nearly one-third of the cases there is an iden-
tifi able cause related to biological or environmental factors. The most common pre-
ventable cause of retardation is  fetal alcohol syndrome,  produced by a mother’s use 
of alcohol while pregnant. Increasing evidence shows that even small amounts of 
alcohol intake can produce intellectual defi cits. One in every 750 infants is born with 
fetal alcohol syndrome in the United States (West & Blake, 2005; Manning & Hoyme, 
2007; Murthy et al., 2009).
Down syndrome, the type of mental retardation experienced by actor Chris 
Burke (discussed at the start of the chapter), represents another major cause of 
mental retardation. Down syndrome results when a person is born with 47 chromo-
somes instead of the usual 46. In most cases, there is an extra copy of the 21 st
chromosome, which leads to problems in how the brain and body develop (Sher-
man et al., 2007). 
In other cases of mental retardation, an abnormality occurs in the structure of 
particular chromosomes. Birth complications, such as a temporary lack of oxygen, 
may also cause retardation. In some cases, mental retardation occurs after birth fol-
lowing a head injury, a stroke, or infections such as meningitis (Plomin, 2005; Bittles, 
Bower, & Hussain, 2007). 
However, the majority of cases of mental retardation are classifi ed as  familial 
retardation, 
in which no apparent biological defect exists but there is a history of 
retardation in the family. Whether the family background of retardation is caused by 
environmental factors, such as extreme continuous poverty leading to malnutrition, 
or by some underlying genetic factor is usually impossible to determine (Zigler et 
al., 2002).
INTEGRATING INDIVIDUALS WITH MENTAL RETARDATION 
Important advances in the care and treatment of those with retardation have been 
made since the Education for All Handicapped Children Act (Public Law 94-142) 
was passed by Congress in the mid-1970s. In this federal law, Congress stipulated 
that people with retardation are entitled to a full education and that they must be 
educated and trained in the least restrictive environment. The law increased the 
educational opportunities for individuals with mental retardation, facilitating their 
integration into regular classrooms as much as possible—a process known as main-
streaming (Katsiyannis, Zhang, & Woodruff, 2005; Aussilloux & Bagdadli, 2006; 
Gibb et al., 2007).