Childhood disintegrative disorder

# Overview
Childhood disintegrative disorder (CDD), also known as Heller's syndrome and disintegrative psychosis, is a rare condition characterized by late onset (>3 years of age) of developmental delays in language, social function, and motor skills. Researchers have not been successful in finding a cause for the disorder.
CDD has some similarity to autism, but an apparent period of fairly normal development is often noted before a regression in skills or a series of regressions in skills. Many children are already somewhat delayed when the illness becomes apparent, but these delays are not always obvious in young children.
The age at which this regression can occur varies, and can be from age 2-10 with the definition of this onset depending largely on opinion.
Regression can be very sudden, and the child may even voice concern about what is happening, much to the parent's surprise. Some children describe or appear to be reacting to hallucinations, but the most obvious symptom is that skills apparently attained are lost.  This has been described by many writers as a devastating condition, affecting both the family and the individual's future. As is the case with all pervasive developmental disorder categories, there is considerable controversy around the right treatment for CDD.
The syndrome was originally described by Austrian educator Theodore Heller in 1908, 35 years before Leo Kanner described autism, but it has not been officially recognised until recently. Heller used the name dementia infantilis for the syndrome.

# Signs and symptoms
A child affected with childhood disintegrative disorder shows normal development, generally up to an age of 2 years, and he/she acquires "normal development of age-appropriate verbal and nonverbal communication, social relationships, motor, play and self-care skills" comparable to other children of the same age. However, from around the age of 2 through the age of 10, skills acquired are lost almost completely in at least two of the following six functional areas:
- Language skills
- Receptive language skills
- Social skills & self-care skills
- Control over bowel and bladder
- Play skills
- Motor skills
Lack of normal function or impairment also occurs in at least two of the following three areas:
- Social interaction
- Communication
- Repetitive behavior & interest patterns

# Causes
The exact causes of childhood disintegrative disorder are still unknown. Sometimes CDD surfaces abruptly within days or weeks, while in other cases it develops over a longer period of time. A Mayo Clinic report indicates: "Comprehensive medical and neurological examinations in children diagnosed with childhood disintegrative disorder seldom uncover an underlying medical or neurological cause. Although the occurrence of epilepsy is higher in children with childhood disintegrative disorder, experts don't know whether epilepsy plays a role in causing the disorder." CDD has also been associated with certain other conditions, particularly the following:
- Lipid storage diseases: In this condition, a toxic buildup of excess fats (lipids) takes place in the brain and nervous system.
- Subacute sclerosing panencephalitis: Chronic infection of the brain by a form of the measles virus causes subacute sclerosing panencephalitis. This condition leads to brain inflammation and the death of nerve cells.
- Tuberous sclerosis (TSC): TSC is a genetic disorder. In this disorder, tumors may grow in the brain and other vital organs like kidneys, heart, eyes, lungs, and skin. In this condition, noncancerous (benign) tumors grow in the brain.

# Treatment
There is no permanent cure for CDD - loss of language and skills related to social interaction and self-care are rather serious. The affected children face permanent disabilities in certain areas and require long term care. Treatment of CDD involves both behavior therapy and medications.
- Behavior therapy: Its aim is to teach the child to relearn language, self-care and social skills. The programs designed in this respect "use a system of rewards to reinforce desirable behaviors and discourage problem behavior." The behavior therapy is used by a number of health care personnel from different fields like psychologists, speech therapists, physical therapists and occupational therapists. At the same time, parents, teachers and caregivers also use the behavior therapy. A consistent approach by all concerned result into a better treatment.
- Medications: There are no medications available to treat directly CDD. Antipsychotic medications are used to treat severe behavior problems like aggressive stance and repetitive behavior patterns. Anticonvulsant medications are used to control seizures.