Currently considered a neurodevelopmental disorder, intellectual disability (formerly mental retardation) is a condition characterized by significant deficits in intellectual functioning and concomitant limitations in terms of adaptive functioning (personal autonomy, social participation, communication). The onset is typically located in the age of development and severity is generally traced back to one of four conventional levels: mild, moderate, severe, extreme. In milder cases, the characteristics may include various aspects including:
- learning difficulties relating to writing, reading, and numeracy;
- lack of understanding of the concept of time and money;
- impaired abstract thinking and executive functions (planning, strategy development, prioritization and cognitive flexibility);
- limited understanding of health risks;
- difficulty carrying out normal daily activities (e.g. shopping, using transport, managing finances and housing);
- immaturity in social relationships (inadequacy in relating to others, naivety and credulity)
The factors capable of causing the disorder are various and generally attributable to three types:
prenatal factors: genetic syndromes (eg Down syndrome) and metabolic disorders (eg phenylketonuria), brain malformations, maternal diseases or exposure of the mother to harmful agents or use of harmful substances (eg alcohol and drugs).
perinatal factors: events and complications related to pregnancy and childbirth.
postnatal factors: traumatic brain injuries, medical conditions occurring in childhood, seizure disorders, infections, severe and chronic social deprivation, various types of intoxication (eg lead or mercury).
Intellectual disability affects about 1% of the general population, and to a greater extent males than females. The intervention usually involves an integrated multidisciplinary approach aimed primarily at improving the degree of adaptation of the individual. An essential element is therefore given by the identification of the factors (intrinsic and / or extrinsic) that hinder the performance of normal activities, and by the modification of inappropriate behavior. Although the disorder tends to persist throughout life, early and adequate interventions can significantly improve the adaptive functioning of the individual, significantly improving the quality of life and allowing, in milder cases, to obtain satisfactory recoveries and adequate development.