What are developmental disorders?

Causes and Symptoms

According to the revised fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (known as the DSM-IV-TR), published in 2000 by the American Psychiatric Association, the developmental disorders may be categorized into five distinct disorders that all share the central feature of childhood development that is outside the norm in some manner. These disorders are included under the heading of pervasive developmental disorders in the DSM-IV-TR. The term pervasive is used to indicate the extensive developmental deficits found among these disorders. The five pervasive developmental disorders in the DSM-IV-TR are autistic disorder, Rett syndrome, childhood disintegrative disorder, Asperger syndrome, and pervasive developmental disorder not otherwise specified (PDD-NOS).

Autistic disorder is probably the best known of the disorders in the developmental disorders group. The disorder has an onset before age three but may not be formally diagnosed until some years later. Children with autistic disorder do not commonly show any unusual physical characteristics, but they demonstrate a number of behavioral, social, and affective symptoms. There are usually major deficiencies in the capacity to show social relatedness to others, including parents. The social smile is absent during infancy, and autistic children continue to show deficits in play activities and social attachments throughout their lives. There is an inability to understand or infer the feelings and mental state of other people around them. Language development is usually limited, with difficulties in communicating ideas even when the vocabulary is present. Delayed mental development occurs in a high percentage of children with autism, with greatest deficits in abstract reasoning and social understanding. Children from an early age do not show interactive play activity but rather engage in repetitious actions such as rocking and other unusual mannerisms. Children with autism usually form attachments to inanimate objects rather than to people. Their mood is usually marked with sudden changes and potentially aggressive outbursts. Although the exact cause in unknown, autistic disorder is considered to have a biological cause with a high genetic vulnerability. Research has indicated that two regions on chromosomes 2 and 7 contain genes involved with autistic disorder. Studies suggest that abnormal levels of serotonin and other neurotransmitters in the brain are found because there is a disruption of normal brain development early in fetal development caused by defects in the genes. The temporal lobe area of the brain has been implicated in the development of autism since this area is strongly associated with social development.

Rett syndrome features a period of normal development for approximately six months after birth that is followed by deterioration of functioning. Symptoms such as encephalopathy, seizures, breathing difficulties, loss of purposeful hand movements, loss of social engagement with others, poor coordination, and severely impaired language development then develop. The growth of the head circumference slows and produces microcephaly. The child begins to show repetitious movements such as hand-wringing and problems walking. The condition is progressive, and the skill level remains at the level of the first year of life. Children may live for ten years or more but must use a wheelchair as a result of muscle wasting. The cause of Rett syndrome has been identified as related to a genetic mutation. The gene is located at the Xq28 site on the X chromosome. Only one of the two X chromosomes need have the mutation in order for it to cause the disorder. This means that it is an X-linked dominant disorder. Rett syndrome is a rare condition usually found in females.

Childhood disintegrative disorder is diagnosed when there is marked regression or deterioration in a number of areas of functioning after age two. Children with this disorder begin to lose language and social skills previously developed in the first two years of life. Both bowel and bladder control as well as manual skills can be lost. It is common for these children to exhibit high levels of anxiety as the deterioration progresses. Children with this disorder also typically develop seizures. The cause of childhood disintegrative disorder is unknown, but it is considered to be related to some central nervous system pathology.

Asperger syndrome is marked with symptoms of severe and sustained impairments in social interactions. Repetitive patterns of behavior are commonly seen. In contrast to autism, children with Asperger syndrome do not exhibit significant delays in language or cognitive development. Common characteristics of Asperger syndrome include a lack of empathy toward the feelings of others, minimal social interactions, limited ability to form friendships, pedantic and monotonic speech, and intense fascination with trivial topics learned in rote fashion. The cause of Asperger syndrome is unknown but is believed to have a genetic base. Current research suggests that a tendency toward the condition may run in families. Children with Asperger syndrome are also at risk for other psychiatric problems, including depression, attention-deficit disorder, schizophrenia, and obsessive-compulsive disorder. Persons with Asperger syndrome have a variable
prognosis depending upon their cognitive abilities and language skills, but all continue into adulthood showing an awkward manner toward other adults and lack of comfort in social settings. Asperger syndrome is usually first diagnosed in children between the ages of two and six.

PDD-NOS is the fifth developmental disorder described in the DSM-IV-TR. It is viewed as a severe impairment in communication skills with deficiencies in social behavior. It differs from autistic disorder in terms of the severity of symptoms, and persons diagnosed with this disorder experience better functioning into adulthood than those with autistic disorder.

Treatment and Therapy

The goal for treatment of autistic disorder is to increase socially acceptable behaviors and decrease or extinguish unusual actions such as rocking and self-injurious behaviors. Therapy attempts to improve verbal and nonverbal communication skills to enhance interactions with other people. Therapy usually involves both educational and behavioral interventions with structured classroom training using behavioral techniques that employ rewards or positive reinforcements. Treatments for children with autistic disorder require a great deal of structure and repetition. Family members often participate in counseling sessions to help with the stressors of raising a child with autistic disorder. Medications are used as an adjunct to educational and behavioral treatments to diminish temper tantrums, self-injurious behaviors such as head banging, and hyperactivity. Antipsychotic medications such as risperidone and haloperidol are the most commonly used adjunctive treatments.

Rett syndrome has limited treatment options. The focus is on providing symptomatic relief whenever possible and structured behavioral techniques of positive rewards to concentrate on positive behaviors. Anticonvulsive medications are used to control seizures that can develop in this disorder and also diminish self-injurious behaviors. Physical therapy can assist with the distress associated with muscle deterioration.

Childhood disintegrative disorder is treated with similar methods as used in autistic disorder. Highly structured educational and behavioral programs are used to maintain the limited language and cognitive skills that had developed prior to the onset of the disorder.

Asperger syndrome treatments depend upon the level of functioning present among those with this disorder. Emphasis is usually placed upon improving social skills and adaptive functioning in social situations.

Treatment for PDD-NOS is largely the same as used with autistic disorder. Children with this disorder have a higher functioning of language skills than found with autistic disorder; consequently, the educational and behavioral treatments are supplemented with individual psychotherapy.

Perspective and Prospects

Autistic disorder was initially identified in 1867 by psychiatrist Henry Maudsley, but it was not until 1943 that Leo Kanner coined the term infantile autism and carefully described the associated signs and symptoms of the condition. Even with this description, many children with autism received the diagnosis of childhood schizophrenia. This tendency toward misdiagnosis continued into the 1980s. When considering the causes for the development of infantile autism, Kanner initially hypothesized that infantile autism was caused by emotionally unresponsive or “refrigerator” mothers who were unable to provide nurturance and emotional warmth to their newborn infants. Some children reacted to this emotional coldness by turning inward as a defense mechanism. Because of this defense, the child with autism focused on his or her inner world and did not develop communication skills. The child with autism usually focuses on inanimate objects rather than people and exhibits repetitious or self-stimulating behaviors such as rocking to gain personal satisfaction. Additions to this theoretical idea focused on the unresponsiveness of both parents toward the child and feelings of rage directed toward the child. Theories focusing on parental factors have since been discarded in favor of the current emphasis on identifying biological and genetic factors in the development of autism.

Rett syndrome was first identified by pediatrician Andreas Rett in 1966. Practicing in Austria, Rett based his descriptions on a pool of twenty-two girls who had developed normally until they were around six months of age. Rett published his findings in several German medical journals, but the information was largely ignored in the rest of the world. Awareness about the disorder increased when Rett published a description of the disease in English in 1977, but it was a 1983 article that appeared in the mainstream English-language journal Annals of Neurology that finally raised the recognition of this disorder.

Childhood disintegrative disorder was first described in 1908 by Viennese remedial teacher Theodor Heller. He described six children who had unexpectedly developed a severe mental deterioration between their third and fourth years of life, after previously normal development. Heller termed the condition dementia infantilis, and it was subsequently called Heller’s syndrome. The disorder is more often diagnosed in males than in females. Although the DSM-IV-TR uses two years of age as the standard for its diagnosis, most cases emerge when a child is between three and four years of age.

Asperger syndrome was first described in 1944 by Austrian pediatrician Hans Asperger, who called the condition autistic psychopathy. Asperger described a number of children, and his descriptions were close to Kanner’s idea of infantile autism. Asperger’s portrayals differed from Kanner’s, however, in that speech was less commonly delayed and the onset appeared to be somewhat later. The children that Asperger described were seen to have social behavior that was labeled as odd or unusual. Asperger called the children with this condition “little professors” because of their formal manner when talking about their favorite topics using great detail. Asperger also suggested that similar problems could be observed in the children's family members, particularly their fathers. Most of the scientific literature concerning Asperger’s discovery initially appeared in European professional journals until Asperger syndrome was made official in 1994, when the diagnosis was added to the DSM-IV.

In 2013, the American Psychiatric Association published the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, known as DSM-5. This edition made significant changes to a number of classification systems, perhaps most notably the classification of pervasive developmental disorders. Autistic disorder, Asperger syndrome, childhood disintegrative disorder, Rett syndrome, and PDD-NOS were subsumed under the category autism spectrum disorder. This change was met with criticism from some members of the medical community; however, others argued that the new system would aid medical professionals in making diagnoses.

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