From the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR®). ISBN 978-0-89042-025-6
©2000 American Psychiatric Association
Pervasive Developmental Disorders
Pervasive Developmental Disorders are characterized by severe and pervasive impairment in several areas of development: reciprocal social interaction skills, communication skills, or the presence of stereotyped behavior, interests, and activities. The qualitative impairments that define these conditions are distinctly deviant relative to the individual’s developmental level or mental age. This section contains Autistic Disorder, Rett's Disorder, Childhood Disintegrative Disorder, Asperger’s Disorder, and Pervasive Developmental Disorder Not Otherwise Specified. These disorders are usually evident in the first years of life and are often associated with some degree of Mental Retardation, which, if present, should be coded on Axis II. The Pervasive Developmental Disorders are sometimes observed with a diverse group of other general medical conditions (e.g., chromosomal abnormalities, congenital infections, structural abnormalities of the central nervous system). If such conditions are present, they should be noted on Axis III. Although terms like ”psychosis" and "childhood schizophrenia" were once used to refer to individuals with these conditions, there is considerable evidence to suggest that the Pervasive Developmental Disorders are distinct from Schizophrenia (however, an individual with Pervasive Developmental Disorder may occasionally later develop Schizophrenia).
299.00 Autistic Disorder
Diagnostic Features
The essential features of Autistic Disorder are the presence of markedly abnormal or impaired development in social interaction and communication and a markedly restricted repertoire of activity and interests. Manifestations of the disorder vary greatly depending on the developmental level and chronological age of the individual. Autistic Disorder is sometimes referred to as early infantile autism, childhood autism, or Kanners's autism.
The impairment in reciprocal social interaction is gross and sustained. There may be marked impairment in the use of multiple nonverbal behaviors (e.g., eye-to-eye gaze, facial expression, body postures and gestures) to regulate social interaction and communication (Criterion Ala). There may be failure to develop peer relationships appropriate to developmental level (Criterion Alb) that may take different forms at different ages. Younger individuals may have little or no interest in establishing friendships. Older individuals may have an interest in friendship but lack understanding of the conventions of social interaction. There may be a lack of spontaneous seeking to share enjoyment, interests, or achievements with other people (e.g., not seeking to snare enjoyment, interests, or achievements with other people (e.g., not showing, bringing, or pointing out objects they find interesting) (Criterion Alc). Lack of social or emotional reciprocity may be present (e.g., not actively participating in simple social play or games, preferring solitary activities, or involving others in activities only as tools or "mechanical" aids) (Criterion Ald). Often an individual’s awareness of others is markedly impaired. Individuals with this disorder may be oblivious to other children (including siblings), may have no concept of the needs of others, or may not notice another person’s distress.
The impairment in communication is also marked and sustained and affects both verbal and nonverbal skills. There may be delay in, or total lack of, the development of spoken language (Criterion A2a). In individuals who do speak, there may be marked impairment in the ability to initiate or sustain a conversation with others (Criterion A2b), or a stereotyped and repetitive use of language or idiosyncratic language (Criterion A2c). There may also be a lack of varied, spontaneous makebelieve play or social imitative play appropriate to developmental level (Criterion A2d). When speech does develop, the pitch, intonation, rate, rhythm, or stress may be abnormal (e.g., tone of voice may be monotonous or inappropriate to context or may contain question like rises at ends of statements). Grammatical structures are often immature and include stereotyped and repetitive use of language (e.g., repetition of words or phrases regardless of meaning; repeating jingles or commercials) or idiosyncratic language (i.e., language that has meaning only to those familiar with the individual's communication style). Language comprehension is often very delayed, 299.00 Autistic Disorder and the individual may be unable to understand simple questions or directions. A disturbance in the pragmatic (social use) of language is often evidenced by an inability to integrate words with gestures or understand humor or nonliteral aspects of speech such as irony or implied meaning. Imaginative play is often absent or markedly impaired. These individuals also tend not to engage in the simple imitation games or routines of infancy or early childhood or do so only out of context or in a mechanical way.
Individuals with Autistic Disorder have restricted, repetitive, and stereotyped patterns of behavior, interests, and activities. There may be an encompassing preoccupation with one or more stereotyped and restricted patterns of interest that is abnormal either in intensity or focus (Criterion A3a); an apparently inflexible adherence to specific, nonfunctional routines or rituals (Criterion A3b); stereotyped and repetitive motor mannerisms (Criterion A3c); or a persistent preoccupation with parts of objects (Criterion A3d). Individuals with Autistic Disorder display a markedly restricted range of interests and are often preoccupied with one narrow interest (e.g., dates, phone numbers, radio station call letters). They may line up an exact number of play things in the same manner over and over again or repetitively mimic the actions of a television actor. They may insist on sameness and show resistance to or distress over trivial changes (e.g., a younger child may have a catastrophic reaction to a minor change in the environment such as rearrangement of the furniture or use of a new set of utensils at the dinner table). There is often an interest in nonfunctional routines or rituals or an unreasonable insistence on following routines (e.g., taking exactly the same route to school every day). Stereotyped body movements include the hands (clapping, finger flicking) or whole body (rocking, dipping, and swaying). Abnormalities of posture (eg, walking on tiptoe, odd hand movements and body postures) may be present, These individuals show a persistent preoccupation with parts of objects (buttons, parts of the body). There may also be a fascination with movement (e.g., the spinning wheels of toys, the opening and closing of doors, an electric fan or other rapidly revolving object), The person may be highly attached to some inanimate object (e.g., a piece of string or a rubber band).
The disturbance must be manifest by delays or abnormal functioning in at least one (and often several) of the following areas prior to age 3 years: social interaction, language as used in social communication, or symbolic or imaginative play (Criterion B). In most cases, there is no period of unequivocally normal development, although in perhaps 20% of cases parents report relatively normal development for 1 or 2 years. In such cases, parents may report that the child acquired a few words and lost these or seemed to stagnate developmentally.
By definition, if there is a period of normal development, it cannot extend past age 3 years. The disturbance must not be better accounted for by Rett's Disorder or Childhood Disintegrative Disorder (Criterion C).
Associated descriptive features and mental disorders. In most cases, there is an associated diagnosis of Mental Retardation, which can range from mild to profound. There may be abnormalities in the development of cognitive skills, The profile of cognitive skills is usually uneven, regardless of the general level of intelligence, with verbal skills typically weaker than nonverbal skills. Sometimes special skills are present (e.g., a 4 1/2-year-old girl with Autistic Disorder may be able to "decode" written materials with minimal understanding of the meaning of what is read [hyperlexia] or a l1-year-old boy may have prodigious abilities to calculate dates [calendar calculation]). Estimates of single-word (receptive or expressive) vocabulary are not always good estimates of language level (i.e., actual language skills may be at much lower levels).
Individuals with Autistic Disorder may have a range of behavioral symptoms, including hyperactivity, short attention span, impulsivity, aggressiveness, self-injurious behaviors, and, particularly in young children, temper tantrums. There may be odd responses to sensory stimuli (e.g., a high threshold for pain, oversensitivity to sounds or being touched, exaggerated reactions to light or odors, fascination with certain stimuli). There may be abnormalities in eating (e.g., limiting diet to a few foods, Pica) or sleeping (e.g., recurrent awakening at night with rocking). Abnormalities of mood or affect (e.g., giggling or weeping for no apparent reason, an apparent absence of emotional reaction) may be present. There may be a lack of fear in response to real dangers, and excessive fearfulness in response to harmless objects. A variety of self-injurious behaviors may be present e.g., head banging or finger, hand, or wrist biting). In adolescence or early adult life, individuals with Autistic Disorder who have the intellectual capacity for insight may become depressed in response to the realization of their serious impairment.
Associated laboratory findings. When Autistic Disorder is associated with a general medical condition, laboratory findings consistent with the general medical condition will be observed. There are group differences in some measures of serotonergic activity, but these are not diagnostic for Autistic Disorder. Imaging studies may be abnormal in some cases, but no specific pattern has been clearly identified. EEG abnormalities are common even in the absence of seizure disorders.
Associated physical findings and general medical conditions. Various nonspecific neurological symptoms or signs may be noted (e.g., primitive reflexes, delayed development of hand dominance) in Autistic Disorder. The condition is sometimes observed in association with a neurological or other general medical condition (erg., fragile X syndrome and tuberous sclerosis).
Seizures may develop (particularly in adolescence) in as many as 25% of cases. Both microcephaly and macrocephaly are observed. When other general medical conditions are present, they should be noted on Axis III.
The nature of the impairment in social interaction may change over time in Autistic Disorder and may vary depending on the developmental level of the individual. ln infants, there may be a failure to cuddle; an indifference or aversion to affection or physical contact: a lack of eye contact, facial responsiveness, or socially directed smiles; and a failure to respond to their parents’ voices. As a result, parents may be concerned initially that the child is deaf. Young children with this disorder may treat adults as interchangeable, may cling mechanically to a specific person, or may use the parent’s hand to obtain desired objects without ever making eye contact (as if it were the hand rather than the person that is relevant). Over the course of development, the child may become more willing to be passively engaged in social interaction and may even become more interested in social interaction. However, even in such instances, the child tends to treat other people in unusual ways (e.g., expecting other people to answer ritualized questions in specific ways, having little sense of other peoples boundaries, and being inappropriately intrusive in social interaction). In older individuals, tasks involving long-term memory [e g., train timetables, historical dates, chemical formulas, or recall of the exact words of songs heard years before] may be excellent, but the information tends to be repeated over and over again, regardless of the appropriateness of the information to the social context. Rates of the disorder are four to five times higher in males than in females. Females with the disorder are more likely, how ever, to exhibit more severe Mental Retardation.
The median rate of Autistic Disorder in epidemiological studies is 5 cases per 10,000 individuals, with reported rates ranging from 2 to 20 cases per 10,000 individuals. It remains unclear whether the higher reported rates reflect differences in methodology or an increased frequency of the condition.
By definition, the onset of Autistic Disorder is prior to age 3 years. In some instances, parents will report that they have been worried about the child since birth or shortly afterward because of the child’s lack of interest in social interaction. Manifestations of the disorder in infancy are more subtle and difficult to define than those seen after age 2 years. In a minority of cases, the child may be reported to have developed normally for the first year (or even 2 years) of life. Autistic Disorder follows a continuous course. In school-age children and adolescents, developmental gains in some areas are common (e.g., increased interest in social functioning as the child reaches school age). Some individuals deteriorate behaviorally during adolescence, whereas others improve. Language skills (e.g., presence of communicative speech) and overall intellectual level are the strongest factors related to ultimate prognosis. Available follow up studies suggest that only a small percentage of individuals with the disorder go on as adults to live and work independently. ln about one-third of cases, some degree of partial independence is possible. The highest functioning adults with Autistic Disorder typically continue to exhibit problems in social interaction and communication along with markedly restricted interests and activities.
There is an increased risk of Autistic Disorder among siblings of individuals with the disorder, with approximately 5% of siblings also exhibiting the condition. There also appears to be risk for various developmental difficulties in affected siblings.
Periods of developmental regression may be observed in normal development, but these are neither as severe or as prolonged as in Autistic Disorder. Autistic Disorder must be differentiated from other Pervasive Developmental Disorders. Rett's Disorder differs from Autistic Disorder in its characteristic sex ratio and pattern of deficits. Rett's Disorder has been diagnosed only in females, whereas Autistic Disorder occurs much more frequently in males. ln Rett's Disorder, there is a characteristic pattern of head growth deceleration, loss of previously acquired purposeful hand skills, and the appearance of poorly coordinated gait or trunk movements. Particularly during the preschool years, individuals with Rett's Disorder may exhibit difficulties in social interaction similar to those observed in Autistic Disorder, but these tend to be transient. Autistic Disorder differs from Childhood Disintegrative Disorder, which has a distinctive pattem of severe developmental regression in multiple areas of functioning following at least 2 years of normal development. In Autistic Disorder, developmental abnormalities are usually noted within the first year of life. When information on early development is unavailable or when it is not possible to document the required period of normal development, the diagnosis of Autistic Disorder should be made. Asperger’s Disorder can be distinguished from Autistic Disorder by the lack of delay or deviance in early language development. Asperger’s Disorder is not diagnosed if criteria are met for Autistic Disorder.
Schizophrenia with childhood onset usually develops after years of normal, or near normal, development. An additional diagnosis of Schizophrenia can be made if an individual with Autistic Disorder develops the characteristic features of Schizophrenia (see p. 298) with active-phase symptoms of prominent delusions or hallucinations that last for at least 1 month. In Selective Mutism, the child usually exhibits appropriate communication skills in certain contexts and does not have the severe impairment in social interaction and the restricted pattems of behavior associated with Autistic Disorder. In Expressive Language Disorder and Mixed ReceptiveExpressive Language Disorder, there is a language impairment, but it is not associated with the presence of a qualitative impairment in social interaction and restricted, repetitive, and stereotyped pattems of behavior. It is sometimes difficult to determine whether an additional diagnosis of Autistic Disorder is warranted in an individual with Mental Retardation, especially if the Mental Retardation is Severe or Profound. An additional diagnosis of Autistic Disorder is reserved for those situations in which there are qualitative deficits in social and communicative skills and the specific behaviors characteristic of Autistic Disorder are present. Motor stereotypies are characteristic of Autistic Disorder; an additional diagnosis of Stereotypic Movement Disorder is not given when these are better accounted for as part of the presentation of Autistic Disorder. Symptoms of overactivity and inattention are frequent in Autistic Disorder, but a diagnosis of Attention-Deficit/Hyperactivity Disorder is not made if Autistic Disorder is present.
A. A total of six (or more) items from (1), (2), and (3), with at least two from (1), and one each from (2) and (3):
1. qualitative impairment in social interaction, as manifested by at least two of the following:
a. marked impairment in the use of multiple nonverbal behaviors such as eye-to-eye gaze, facial expression, body postures, and gestures to regulate social interaction
b. failure to develop peer relationships appropriate to developmental level
c. a lack of spontaneous seeking to share enjoyment, interests, or achievements with other people (e.g., by a lack of showing, bringing, or pointing out objects of interest)
d. lack of social or emotional reciprocity
2. qualitative impairments in communication as manifested by at least one of the following:
a. delay in, or total lack of, the development of spoken language (not accompanied by an attempt to compensate through alternative modes of communication such as gesture or mime)
b. in individuals with adequate speech, marked impairment in the ability to initiate or sustain a conversation with others
c. stereotyped and repetitive use of language or idiosyncratic language
d. lack of varied, spontaneous make-believe play or social imitative play appropriate to developmental level
3. restricted repetitive and stereotyped patterns of behavior, interests, and activities, as manifested by at least one of the following:
a. encompassing preoccupation with one or more stereotyped and restricted patterns of interest that is abnormal either in intensity or focus
b. apparently inflexible adherence to specific, nonfunctional routines or rituals
c. stereotyped and repetitive motor mannerisms (e.g., hand or finger flapping or twisting, or complex whole-body movements)
d. persistent preoccupation with parts of objects
B. Delays or abnormal functioning in at least one of the following areas, with onset prior to age 3 years: (1) social interaction, (2) language as used in social communication, or (3) symbolic or imaginative play.
C. The disturbance is not better accounted for by Rett's Disorder or Childhood Disintegrative Disorder.
299.80 Rett's Disorder
Diagnostic Features
The essential feature of Rett's Disorder is the development of multiple specific deficits following a period of normal fimctioning after birth. Individuals have an apparently normal prenatal and perinatal period (Criterion A1) with normal psychomotor development through the first 5 months of life (Criterion A2). Head circumference at birth is also within normal limits (Criterion A3). Between ages 5 and 48 months, head growth decelerates (Criterion Bl). There is a loss of previously acquired purposeful hand skills between ages 5 and 30 months, with the subsequent development of characteristic stereotyped hand movements resembling hand-wringing or hand washing (Criterion B2). Interest in the social environment diminishes in the first few years after the onset of the disorder (Criterion B3), although social interaction may often develop later in the course. Problems develop in the coordination of gait or trunk movements (Criterion B4). There is also severe impairment in expressive and receptive language development, with severe psychomotor retardation (Criterion B5).
Associated Features and Disorders
Rett's Disorder is typically associated with Severe or Profound Mental Retardation, which, if present, should be coded on Axis II. There are no specific laboratory findings associated with the disorder. There may be an increased frequency of EEG abnormalities and seizure disorder in individuals with Rett's Disorder. Nonspecific abnormalities on brain imaging have been reported. Preliminary data suggest that a genetic mutation is the cause of some cases of Rett's Disorder.
Prevalence
Data are limited to mostly case series, and it appears that Rett's Disorder is much less common than Autistic Disorder. This disorder has been reported only in females. Co u rse The pattem of developmental regression is highly distinctive. Rett's Disorder has its onset prior to age 4 years, usually in the first or second year of life. The duration of the disorder is lifelong, and the loss of skills is generally persistent and progressive. In most instances, recovery is quite limited, although some very modest developmental gains may be made and interest in social interaction may be observed as individuals enter later childhood or adolescence. The communicative and behavioral difficulties usually remain relatively constant throughout life.
Differential Diagnosis
Periods of developmental regression may be observed in normal development, but these are neither as severe or as prolonged as in Rett's Disorder. For the differential diagnosis between Rett’s Disorder and Autistic Disorder, see p. 74. Rett’s Disorder differs from Childhood Disintegrative Disorder and Asperger's Disorder in its characteristic sex ratio, onset, and pattern of deficits. Rett’s Disorder has been diagnosed only in females, whereas Childhood Disintegrative Disorder and Asperger’s Disorder appear to be more common in males. The onset of symptoms in Rett's Disorder can begin as early as age 5 months, whereas in Childhood Disintegrative Disorder the period of normal development is typically more prolonged (i.e., at least until age 2 years). In Rett’s Disorder, there is a characteristic pattern of head growth deceleration, loss of previously acquired purposeful hand skills, and the appearance of poorly coordinated gait or trunk movements. In contrast to Asperger's Disorder, Rett’s Disorder is characterized by a severe impairment in expressive and receptive language development.
Diagnostic criteria for 299.80 Rett’s Disorder
A. All of the following:
1. apparently normal prenatal and perinatal development
2. apparently normal psychomotor development through the first 5 months after birth
3. normal head circumference at birth
B. Onset of all ofthe following after the period of normal development:
1. deceleration of head growth between ages 5 and 48 months
2. loss of previously acquired purposeful hand skills between ages 5 and 30 months with the subsequent development of stereotyped hand movements (e.g., hand-wringing or hand washing)
3. loss of social engagement early in the course (although often social interaction develops later)
4. appearance of poorly coordinated gait or trunk movements
5. severely impaired expressive and receptive language development with severe psychomotor retardation
299.1 0 Childhood Disintegrative Disorder
Diagnostic Features
The essential feature of Childhood Disintegrative Disorder is a marked regression in multiple areas of functioning following a period of at least 2 years of apparently normal development (Criterion A). Apparently normal development is reflected in age appropriate verbal and nonverbal communication, social relationships, play, and adaptive behavior. After the first 2 years of life (but before age 10 years), the child has a clinically significant loss of previously acquired skills in at least two of the following areas: expressive or receptive language, social skills or adaptive behavior, bowel or bladder control, play, or motor skills (Criterion B). Most typically, acquired skills are lost in almost all areas.
Individuals with this disorder exhibit the social and communicative deficits and behavioral features generally observed in Autistic Disorder (see p. 70). There is qualitative impairment in social interaction (Criterion C1) and in communication (Criterion C2), and restricted, repetitive, and stereotyped patterns of behavior, interests, and activities (Criterion C3). The disturbance is not better accounted for by another specific Pervasive Developmental Disorder or by Schizophrenia (Criterion D). This condition has also been termed Hellefs syndrvnm, denzentin ivifmrtilis, or disintegrzztive psychosis.
Associated Features and Disorders
Childhood Disintegrative Disorder is usually associated with Severe Mental Retardation, which, if present, should be coded on Axis II. Various nonspecific neurological symptoms or signs may be noted. There seems to be an increased frequency of EEG abnormalities and seizure disorder. Although it appears likely that the condition is the result of some insult to the developing central nervous system, no precise mechanism has been identified. The condition is occasionally observed in association with a general medical condition (e.g., metachromatic leukodystrophy, Schilder’s disease) that might account for the developmental regression. In most instances, however, extensive investigation does not reveal such a condition. lf a neurological or other general medical condition is associated with the disorder, it should be recorded on Axis lll. The laboratory findings will reflect any associated general medical conditions.
Prevalence
Epidemiological data are limited, but Childhood Disintegrative Disorder appears to be very rare and much less common than Autistic Disorder, although the condition is likely Luiderdiagnosed. Although initial studies suggested an equal sex ratio, the most recent data suggest that the condition is more common among males.
Course
By definition, Childhood Disintegrative Disorder can only be diagnosed if the symptoms are preceded by at least 2 years of normal development and the onset is prior to age 10 years. When the period of normal development has been quite prolonged (5 or more years), it is particularly important to conduct a thorough physical and neurological examination to assess for the presence of a general medical condition. ln most cases, the onset is between ages 3 and 4 years and may be insidious or abrupt. Premonitory signs can include increased activity levels, irritability, and anxiety followed by a loss of speech and other skills. During this time, the child may also lose interest in the environment. Usually the loss of skills reaches a plateau, after which some limited improvement may occur, although improvement is rarely marked. In other instances, especially when the disorder is associated with a progressive neurological condition, the loss of skills is progressive. This disorder follows a continuous course, and in the majority of cases, the duration is lifelong. The social, communicative, and behavioral difficulties remain relatively constant throughout life.
Differential Diagnosis
Periods of regression may be observed in normal development, but these are neither as severe or as prolonged as in Childhood Disintegrative Disorder. Childhood Disintegrative Disorder must be differentiated from other Pervasive Developmental Disorders. For the differential diagnosis with Autistic Disorder, see p. 74. For the differential diagnosis with Rett’s Disorder, see p. 76. In contrast to Asperger’ s Disorder, Childhood Disintegrative Disorder is characterized by a clinically significant loss in previously acquired skills and a greater likelihood of Mental Retardation. In Asperger’s Disorder, there is no delay in language development and no marked loss of developmental skills.
Childhood Disintegrative Disorder must be differentiated from a dementia with onset during infancy or childhood. Dementia occurs as a consequence of the direct physiological effects of a general medical condition (e.g., head trauma), whereas Childhood Disintegrative Disorder typically occurs in the absence of an associated general medical condition.
Diagnostic criteria for 299.10 Childhood Disintegrative Disorder
A. Apparently normal development for at least the first 2 years after birth as manifested by the presence of age-appropriate verbal and nonverbal communication, social relationships, play, and adaptive behavior.
B. Clinically significant loss of previously acquired skills (before age 10 years) in at least two of the following areas:
1. expressive or receptive language
2. social skills or adaptive behavior
3. bowel or bladder control
4. play
5. motor skills
C. Abnormalities of functioning in at least two of the following areas:
1. qualitative impairment in social interaction (e.g., impairment in nonverbal behaviors, failure to develop peer relationships, lack of social or emotional reciprocity)
2. qualitative impairments in communication (e.g., delay or lack of spoken language, inability to initiate or sustain a conversation, stereotyped and repetitive use of language, lack of varied make-believe play)
3. restricted, repetitive, and stereotyped patterns of behavior, interests, and activities, including motor stereotypies and mannerisms
D. The disturbance is not better accounted for by another specific Pervasive Developmental Disorder or by Schizophrenia.
299.80 Asperger's Disorder
Diagnostic Features
The essential features of Asperger’s Disorder are severe and sustained impairment in social interaction (Criterion A) and the development of restricted, repetitive patterns of behavior, interests, and activities (Criterion B). The disturbance must cause clinically significant impairment in social, occupational, or other important areas of functioning (Criterion C). In contrast to Autistic Disorder, there are no clinically significant delays or deviance in language acquisition (eg., single non-echoed words are used communicatively by age 2 years, and spontaneous communicative phrases are used by age 3 years) (Criterion D), although more subtle aspects of social communication (e.g., typical give-and-take in conversation) may be affected. Ln addition, during the first 3 years of life, there are no clinically significant delays in cognitive development as manifested by expressing normal curiosity about the environment or in the acquisition of age-appropriate learning skills and adaptive behaviors (other than in social interaction) (Criterion E). Finally, the criteria are not met for another specific Pervasive Developmental Disorder or for Schizophrenia (Criterion F). This condition is also termed Asperger's syndrome.
The impairment in reciprocal social interaction is gross and sustained. There may be marked impairment in the use of multiple nonverbal behaviors (e.g., eye-to-eye gaze, facial expression, body postures and gestures) to regulate social interaction and communication (Criterion A1). There may be failure to develop peer relationships appropriate to developmental level (Criterion A2) that may take different forms at different ages. Younger individuals may have little or no interest in establishing friendships. Older individuals may have an interest in friendships but lack understanding of the conventions of social interaction. There may be a lack of spontaneous seeking to share enjoyment, interests, or achievements with other people (e.g., not showing, bringing, or pointing out objects they find interesting) (Criterion A3). Lack of social or emotional reciprocity may be present (e.g., not actively participating in simple social play or games, preferring solitary activities, or involving others in activities only as tools or "mechanical" aids) (Criterion A4). Although the social deficit in Asperger’s Disorder is severe and is defined in the same way as in Autistic Disorder, the lack of social reciprocity is more typically manifest by an eccentric and one-sided social approach to others (e.g., pursuing a conversational topic regardless of others’ reactions) rather than social and emotional indifference.
As in Autistic Disorder, restricted, repetitive patterns of behavior, interests, and activities are present (Criterion B). Often these are primarily manifest in the development of encompassing preoccupations about a circumscribed topic or interest, about which the individual can amass a great deal of facts and information (Criterion Bl). These interests and activities are pursued with great intensity often to the exclusion of other activities.
The disturbance must cause clinically significant impairment in social adaptation, which in tum may have a significant impact on self-sufficiency or on occupational or other important areas of functioning (Criterion C). The social deficits and restricted patterns of interests, activities, and behavior are the source of considerable disability.
In contrast to Autistic Disorder, there are no clinically significant delays in early language (e.g., single words are used by age 2, communicative phrases are used by age 3) (Criterion D). Subsequent language may be unusual in terms of the individual’s preoccupation with certain topics and his or her verbosity. Difficulties in communication may result from social dysfunction and the failure to appreciate and utilize conventional rules of conversation, failure to appreciate nonverbal cues, and limited capacities for self-monitoring.
Individuals with Asperger's Disorder do not have clinically significant delays in cognitive development or in age~appropriate self-help skills, adaptive behavior (other than in social interaction), and curiosity about the environment in childhood (Criterion E). Because early language and cognitive skills are within normal limits in the first 3 years of life, parents or caregivers are not usually concerned about the child's development during that time, although upon detailed interviewing they may recall unusual behaviors. The child may be described as talking before walking, and indeed parents may believe the child to be precocious (e.g., with a rich or ”adult" vocabulary). Although subtle social problems may exist, parents or caregivers often are not concerned until the child begins to attend a preschool or is exposed to same-age children; at this point the child's social difficulties with same-age peers may become apparent.
By definition the diagnosis is not given if the criteria are met for any other specific Pervasive Developmental Disorder or for Schizophrenia (although the diagnoses of Asperger's Disorder and Schizophrenia may coexist if the onset of the Asperger’s Disorder clearly preceded the onset of Schizophrenia) (Criterion F).
Associated Features and Disorders
In contrast to Autistic Disorder, Mental Retardation is not usually observed in Asperger's Disorder, although occasional cases in which Mild Mental Retardation is present have been noted (e.g., when the Mental Retardation becomes apparent only in the school years, with no apparent cognitive or language delay in the first years of life). Variability of cognitive functioning may be observed, often with strengths in areas of verbal ability (e.g., vocabulary, rote auditory memory) and weaknesses in nonverbal areas (e.g., visual-motor and visual-spatial skills). Motor clumsiness and awkwardness may be present but usually are relatively mild, although motor difficulties may contribute to peer rejection and social isolation (e.g., inability to participate in group sports). Symptoms of overactivity and inattention are frequent in Asperger’s Disorder, and indeed many individuals with this condition receive a diagnosis of Attention-Deficit/ Hyperactivity Disorder prior to the diagnosis of Asperger’s Disorder. Asperger’s Disorder has been reported to be associated with a number of other mental disorders, including Depressive Disorders.
Specific Age and Gender Features
The clinical picture may present differently at different ages. Often the social disability of individuals with the disorder becomes more striking over time. By adolescence some individuals with the disorder may learn to use areas of strength (e.g., rote verbal abilities) to compensate for areas of weakness. Individuals with Asperger’s disorder may experience victimization by others; this, and feelings of social isolation and an increasing capacity for self-awareness, may contribute to the development of depression and anxiety in adolescence and young adulthood. The disorder is diagnosed much more frequently (at least five times) in males than in females
Prevalence
Definitive data regarding the prevalence of Asperger’s Disorder are lacking.
Course
Asperger's Disorder is a continuous and lifelong disorder. In school-age children, good verbal abilities may, to some extent, mask the severity of the child’s social dysfunction and may also mislead caregivers and teachers - that is, caregivers and teachers may focus on the child’s good verbal skills but be insufficiently aware of problems in other areas (particularly social adjustment). The child’s relatively good verbal skills but be insufficiently aware of problems in other areas (particularly social adjustment). The child’s relatively good verbal skills may also lead teachers and caregivers to erroneously attribute behavioral difficulties to willfulness or stubbornness in the child. Interest in forming social relationships may increase in adolescence as the individuals learn some ways of responding more adaptively to their difficulties - for example, the individual may learn to apply explicit verbal rules or routines in certain stressful situations. Older individuals may have an interest in friendship but lack understanding of the conventions of social interaction and may more likely make relationships with individuals much older or younger than themselves. The prognosis appears significantly better than in Autistic Disorder, as follow-up studies suggest that, as adults, many individuals are capable of gainful employment and personal self-sufficiency.
Familial Pattern
Although the available data are limited, there appears to be an increased frequency of Asperger’s Disorder among family members of individuals who have the disorder. There may also be an increased risk for Autistic Disorder as well as more general social difficulties.
Differential Diagnosis
Asperger’s Disorder must be distinguished from the other Pervasive Developmental Disorders, all of which are characterized by problems in social interaction. It differs from Autistic Disorder in several ways. ln Autistic Disorder there are, by definition, significant abnormalities in the areas of social interaction, language, and play, whereas in Asperger’s Disorder early cognitive and language skills are not delayed significantly. Furthermore, in Autistic Disorder, restricted, repetitive, and stereotyped interests and activities are often characterized by the presence of motor mannerisms, preoccupation with parts of objects, rituals, and marked distress in change, whereas in Asperger’s Disorder these are primarily observed in the all~encompassing pursuit of a circumscribed interest involving a topic to which the individual devotes inordinate amounts of time amassing information and facts. Differentiation of the two conditions can be problematic in some cases. In Autistic Disorder, typical social interaction pattens are marked by self-isolation or markedly rigid social approaches, whereas in Asperger’s Disorder there may appear to be motivation for approaching others even though this is then done in a highly eccentric, one-sided, verbose, and insensitive manner.
Asperger’s Disorder must also be differentiated from Pervasive Developmental Disorders other than Autistic Disorder. Rett' s Disorder differs from Asperger’s Disorder in its characteristic sex ratio and pattem of deficits. Rett’s Disorder has been diagnosed only in females, whereas Asperer’s Disorder occurs much more frequently in males. In Rett's Disorder, there is a characteristic pattern of head growth deceleration, loss of previously acquired purposeful hand skills, and the appearance of poorly coordinated gait or trunk movements. Rett’s Disorder is also associated with marked degrees of Mental Retardation and gross impairments in language and communication.
Asperger’s Disorder differs from Childhood Disintegrative Disorder, which has a distinctive pattern of developmental regression following at least 2 years of normal development. Children with Childhood Disintegrative Disorder also display marked degrees of Mental Retardation and language impairment. In contrast, in Asperger’s Disorder there is no pattern of developmental regression and, by definition, no significant cognitive or language delays.
Schizophrenia of childhood onset usually develops after years of normal, or near normal, development, and characteristic features of the disorder, including hallucinations, delusions, and disorganized speech, are present. In Selective Mutism, the child usually exhibits appropriate communication skills in certain contexts and does not have the severe impairment in social interaction and the restricted patterns of behavior associated with Asperger’s Disorder. Conversely, individuals with Asperger’s Disorder are typically verbose. In Expressive Language Disorder and Mixed Receptive-Expressive Language Disorder, there is language impairment but no associated qualitative impairment in social interaction and restricted, repetitive, and stereotyped patterns of behavior. Some individuals with Asperger's Disorder may exhibit behavioral patterns suggesting Obsessive-Compulsive Disorder, although special clinical attention should be given to the differentiation between preoccupations and activities in Asperger’s Disorder and obsessions and compulsions in ObsessiveCompulsive Disorder. In Asperger's Disorder these interests are the source of some apparent pleasure or comfort, whereas in Obsessive-Compulsive Disorder they are the source of anxiety. Furthermore, Obsessive-Compulsive Disorder is typically not associated with the level of impairment in social interaction and social communication seen in Asperger's Disorder.
The relationship between Asperger’s Disorder and Schizoid Personality Disorder is unclear. In general, the social difficulties in Asperger’s Disorder are more severe and of earlier onset. Although some individuals with Asperger’s Disorder may experience heightened and debilitating anxiety in social settings as in Social Phobia or other Anxiety Disorders, the latter conditions are not characterized by pervasive impairments in social development or by the circumscribed interests typical of Asperger’s Disorder. Asperger’s Disorder must be distinguished from normal social awkwardness and normal age-appropriate interests and hobbies. In Asperger’s Disorder, the social deficits are quite severe and the preoccupations are all-encompassing and interfere with the acquisition of basic skills.
Diagnostic criteria for 299.80 Asperger's Disorder
A. Qualitative impairment in social interaction, as manifested by at least two of the following:
1. marked impairment in the use of multiple nonverbal behaviors such as eye-to-eye gaze, facial expression, body postures, and gestures to regulate social interaction
2. failure to develop peer relationships appropriate to developmental level
3. a lack of spontaneous seeking to share enjoyment, interests, or achievements with other people (e.g., by a lack of showing, bringing, or pointing out objects of interest to other people)
4. lack of social or emotional reciprocity
B. Restricted repetitive and stereotyped patterns of behavior, interests, and activities, as manifested by at least one of the following:
1. encompassing preoccupation with one or more stereotyped and restricted patterns of interest that is abnormal either in intensity or focus
2. apparently inflexible adherence to specific, nonfunctional routines or rituals
3. stereotyped and repetitive motor mannerisms (e.g., hand or finger flapping or twisting, or complex whole-body movements)
4. persistent preoccupation with parts of objects
C. The disturbance causes clinically significant impairment in social, occupational, or other important areas of functioning.
D. There is no clinically significant general delay in language (e.g., single words used by age 2 years, communicative phrases used by age 3 years)
E. There is no clinically significant delay in cognitive development or in the development of age—appropriate self-help skills, adaptive behavior (other than in social interaction), and curiosity about the environment in childhood.
F. Criteria are not met for another specific Pervasive Developmental Disorder or Schizophrenia.
299.80 Pervasive Developmental Disorder Not Otherwise Specified (Including Atypical Autism)
This category should be used when there is a severe and pervasive impairment in the development of reciprocal social interaction associated with impairment in either verbal or nonverbal communication skills or with the presence of stereotyped behavior, interests, and activities, but the criteria are not met for a specific Pervasive Developmental Disorder, Schizophrenia, Schizotypal Personality Disorder, or Avoidant Personality Disorder. For example, this category includes "atypical autism"—presentations that do not meet the criteria for Autistic Disorder because of late age at onset, atypical symptomatology, or subthreshold symptomatology, or all of these.
DSM I, II, III and III-R definitions of Autism are here.
DSM I, II, III and III-R definitions of Autism are here.
