Mental disorder - Mentally challenged people
An intellectual disability arises before, during or in the first months / years after birth. In any case before someone is eighteen years old. If someone has cognitive impairments later in life due to brain damage, for example due to trauma or stroke, you speak of a non-congenital brain injury (NAH) with cognitive (and other) limitations.
There are many different causes for intellectual disability: hereditary and chromosomal disorders (Down syndrome, fragile X syndrome, metabolic disorders), congenital disorders, lack of oxygen at birth, infections before or shortly after birth, being born prematurely (serious prematurity), damage due to drug, alcohol or drug use (fetal alcohol syndrome, FAS).
The severity of an intellectual disability is usually indicated with the IQ. Even though the IQ does not say anything about social functioning, it is an easy measure. The IQ of someone with an intellectual disability says something about their level of development or developmental age.
Table gives a classification of intellectual disabilities according to their severity.
Degree of intellectual disability
|I.Q||Developmental age (in years)||Operate|
|Weakness||70-85||> 11||'Together to school'|
|Light intellectual disability||50 / 55-70||7-11||Partly special education is needed|
|Moderate intellectual disability||35 / 40-50 / 55||4-7||Dependent; some training possible|
|Severe intellectual disability||20 / 25-35 / 40||2-4||Dependent|
|Very serious intellectual disability||<20/25||<2||Full care needed|