Mental Retardation

Essential Concepts

Assessment and clarification of learning, cognitive, and developmental disorders are essential to providing appropriate interventions
Early diagnosis and appropriate and intensive interventions for developmental delay improve prognosis
A systems-based approach is needed to work with developmentally disabled children and families
Inventory strengths as well as deficits and areas of need
Other psychiatric disorders (mood, anxiety, behavioral) are more common in children with mental retardation.

Many children with mental retardation are never referred to a child and adolescent psychiatrist or mental health professional of any kind. Pediatricians, family practitioners, pediatric neurologists, special educators, speech and language and physical or occupational therapists tend to provide services for these children. Birth to Three Early Intervention provides crucial services in the early identification and early treatment intervention of children with developmental and cognitive disorders. However, trainees and practitioners in child and adolescent psychiatry need to be comfortable and competent working with children with these disorders, as the comorbidity with other psychiatric disorders of mood, anxiety, and behavior are extremely high. Working with children with developmental disabilities requires a high degree of comfort and sophistication in collaborating in a multidisciplinary system of care to provide the full range of services needed to optimize outcome.

Basic Principles

It should not be assumed that children with special learning needs will have other psychiatric difficulties. However, children with mental retardation have a three to four times higher incidence of other psychiatric disorders than children with average cognitive skills. Mentally retarded children are at high risk for social ostracism. Additionally, the neuropathology underlying the learning or cognitive dysfunction may contribute to certain aberrant behaviors. Executive and problem-solving skills are impaired concomitantly with the overall cognitive delay.

Diagnostic Criterion and Epidemiology

Mental retardation is diagnosed on Axis II in the DSM multiaxial diagnostic scheme. The diagnosis of mental retardation requires the concomitant impairment in cognitive functioning, as well as impairments in adaptive functioning (person’s effectiveness in meeting age-expected standards in communication, self-care, home living, social/interpersonal skills, use of community resources, self-direction, functional academic skills, work, leisure, health and safety). It is estimated that about 1% of the population meet these criteria. Tables 3.1 and 3.2 define the severity levels of mental retardation, as well as the possible etiologies.

Comorbid Mental Disorders

It is estimated that 30 to 70% of mentally retarded children also suffer from a psychiatric disorder. Neurobiological as well as environmental factors (stigmatization, feeling of failure in school) put these children at very high risk. The most common associated mental disorders are attention deficit
hyperactivity disorder, pervasive developmental disorders, mood and anxiety disorders, stereotypic movement disorder, and mental disorders due to a general medical condition (such as dementia due to head trauma).

Table 3.1. Mental Retardation (Axis II except Borderline on Axis I)