Kaplan + Sadock's Synopsis of Psychiatry, 11e

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31.5 Autism Spectrum Disorder

integrative disorder is characterized by the loss of previously acquired development. Before the onset of childhood disinte- grative disorder (occurring at 2 years or older), language has usually progressed to sentence formation. This skill is strikingly different from the premorbid history of even high-functioning patients with autistic disorder, in whom language generally does not exceed single words or phrases before diagnosis of the dis- order. Once the disorder occurs, however, those with childhood disintegrative disorder are more likely to have no language abil- ities than are high-functioning patients with autistic disorder. In Rett syndrome, the deterioration occurs much earlier than in childhood disintegrative disorder, and the characteristic hand stereotypies of Rett syndrome do not occur in childhood disin- tegrative disorder. Course and Prognosis.  The course of childhood disin- tegrative disorder is variable, with a plateau reached in most cases, a progressive deteriorating course in rare cases, and some improvement in occasional cases to the point of regaining the ability to speak in sentences. Most patients are left with at least moderate mental retardation. Treatment.  Treatment of childhood disintegrative disorder includes the same components available in the treatment of autistic disorder. Asperger’s Disorder The former diagnosis of Asperger’s disorder is characterized by impairment and oddity of social interaction and restricted interest and behavior. Unlike the former autistic disorder, in Asperger’s disorder there are no significant delays in language or cognitive development. In 1944, Hans Asperger, an Austrian physician, described a syndrome that he named “autistic psy- chopathy.” His original description of the syndrome described individuals with normal intelligence who exhibit a qualitative impairment in reciprocal social interaction and behavioral oddities without delays in language development. Asperger’s disorder occurs in a wide variety of severities, including cases in which very subtle social cues are missed, but overall social interactions are mastered. Etiology.  Asperger’s disorder, a version of autism spectrum disorder, has a complex etiology including genetic contribu- tion and potentially environmental and perinatal contributing factors. Diagnosis and Clinical Features.  The clinical features include at least two of the following indications of qualitative social impairment: Markedly abnormal nonverbal communi- cative gestures, the failure to develop peer relationships at the expected level. Restricted interests and patterns of behavior are present, but when they are subtle, they may not be immediately identified or singled out as different from those of other chil- dren. According to DSM-IV-TR, individuals with Asperger’s disorder exhibit no language delay, clinically significant cogni- tive delay, or adaptive impairment. Currently, the clinical phe- notype of Asperger’s disorder is subsumed within the DSM-5 diagnosis of autism spectrum disorder.

several months of intellectual, social, and language function occurring in 3- and 4-year-olds with previously normal func- tion. After the deterioration, the children closely resembled chil- dren with autistic disorder. Epidemiology.  Epidemiological data have been compli- cated by the variable diagnostic criteria used, but childhood dis- integrative disorder is estimated to be much less common than the formerly diagnosed autistic disorder. The prevalence has been estimated to occur in about 1 in 100,000 boys. The ratio of boys to girls is estimated to be between 4 and 8 boys to 1 girl. Etiology.  The cause of childhood disintegrative disorder is unknown, but it has been associated with other neurological conditions, including seizure disorders, tuberous sclerosis, and various metabolic disorders. Diagnosis and Clinical Features.  The diagnosis is made based on features that fit a characteristic age of onset, clinical picture, and course. Cases reported have ranged in onset from ages 1 to 9 years, but in most, the onset is between 3 and 4 years. Whereas previously diagnosed as a separate entity, DSM-5 con- ceives of childhood disintegrative disorder as a subset of autism spectrum disorder. The onset may be insidious over several months or relatively abrupt, with abilities diminishing in days or weeks. In some cases, a child displays restlessness, increased activity level, and anxiety before the loss of function. The core features of the disorder include loss of communication skills, marked regression of reciprocal interactions, and the onset of stereotyped movements and compulsive behavior. Affective symptoms are common, particularly anxiety, as is the regression of self-help skills, such as bowel and bladder control. To receive the diagnosis, a child must exhibit loss of skills in two of the following areas: language, social or adaptive behavior; bowel or bladder control; play; and motor skills. Abnormalities must be present in both of the following catego- ries: reciprocal social communication skills, and restricted and repetitive behavior. The main neurological associated feature is seizure disorder. Ron’s early history was within normal limits. By age 2, he was speaking in sentences, and his development appeared to be pro- ceeding appropriately. At 3½ years of age, he abruptly exhibited a period of marked behavioral regression shortly after the birth of a sibling. Ron lost previously acquired skills in communication and was no longer toilet trained. Ron became more withdrawn and less interested in social interaction, exhibiting various self-stimulatory behaviors repeatedly. Comprehensive medical examination failed to reveal any conditions that might account for this developmental regression. Behaviorally, Ron exhibited features of autism spec- trum disorder. At follow-up at age 12, he spoke only an occasional single word and had severe mental retardation. (Adapted from Fred Volkmar, M.D.)

Differential Diagnosis.  The differential diagnosis of the formerly diagnosed childhood disintegrative disorder includes receptive and expressive language disorder, mental retardation with behavioral problems, and Rett syndrome. Childhood dis-