The new Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) came out in the summer of 1994. There have been numerous changes which affect the diagnoses of Autism and related disorders. This summary will review those changes and the possible impact of these changes on persons with Autism and related disorders.
First, the category of disorders under which Autism falls, Pervasive Developmental Disorders, are now coded in a different location in DSM-IV than in its predecessor, DSM-IIIR. It used to be the case that the Pervasive Developmental Disorders were coded on Axis II, the axis that was reserved for long-term, stable disorders with relatively poor prognosis for improvement. Pervasive Developmental Disorders are now coded on Axis I, the axis that is used to diagnose episodic and more transient clinical disorders. The possible implication of this move is the recognition that symptoms of these disorders can vary and possibly improve with intervention whereas the disorders which remain on Axis II, mental retardation and the personality disorders, are typically long-term and often unresponsive to treatment.
In addition to moving the axis on which these disorders are diagnosed, the diagnostic criteria for Autism has changed slightly, and three Autism-related disorders (which had been recognized in the European community's International Classification of Diseases (ICD) system for awhile) have been added to DSM-IV. In order for a diagnosis of Autism to be made, the person still needs to evidence problems in three broad areas: social interaction, communication, and stereotyped patterns of behavior. However, the number of symptoms which fall under these three broad areas have been reduced from 16 to 12 to make this diagnostic category more homogeneous. The individual needs to evidence 6 symptoms spanning the three broad areas with at least two symptoms indicating social interaction deficits, and one symptom in each of the communication and stereotyped patterns of behavior categories. The symptoms which fall under the social interaction category are: marked impairment in the use of multiple nonverbal behaviors; failure to develop age-appropriate peer relationships; lack of spontaneous seeking to share interests and achievements with others; and lack of social or emotional reciprocity. The symptoms which fall under the communication category are: delay in or lack of spoken language development (with no compensation through alternative modes of communication); in verbal persons, marked impairment in conversational skills; stereotyped and repetitive use of language; and lack of spontaneous age-appropriate make-believe or social imitative play. The symptoms which fall under the stereotyped patterns of behavior category are: preoccupation with at least one stereotyped and restricted patterns of interest to an abnormal degree; inflexible adherence to nonfunctional routines or rituals; stereotyped and repetitive motor mannerisms; and preoccupation with parts of objects. Besides at least 6 of these symptoms, there also needs to be delays in either social interaction, social communication, or symbolic or imaginative play. Another change is that the age of onset of these symptoms has to occur prior to age 3.
A new disorder added to the DSM system is Rett's Disorder. In order for this diagnosis to be made, all of the following need to be present: apparently normal pre- and perinatal development; apparently normal psychomotor development through the first 5 months of life; and normal head circumference at birth. In addition, all of the following symptoms need to occur after a period of normal development: deceleration of head growth between 5-48 months; loss of previously acquired purposeful hand skills between 5-30 months with subsequent stereotyped hand movements (e.g., hand-wringing); loss of social engagement; appearance of poorly coordinated gait; severely impaired expressive and receptive language development; and severe psychomotor retardation. The symptoms of Rett's Disorder are similar to Autism but the prognosis is poorer; and in Autism, the symptoms may or may not have occurred following a period of normal development.
Childhood Disintegrative Disorder is another new diagnosis in DSM-IV. This disorder is also similar to Autism, but there must clearly be evidence of apparently normal development for at least the first 2 years of life (with regard to communication, social relationships, play, and adaptive behavior). This category covers what some professionals refer to as "Regressive Autism" where the individual develops Autistic symptoms much later than a "typical" Autistic child. For a diagnosis of Childhood Disintegrative Disorder to be made, there must be a clinically significant loss of previously acquired skills (before age 10) in at least two areas: expressive or receptive language; social skills or adaptive behavior; bowel or bladder control; play; or motor skills. Additionally, there needs to be abnormalities of functioning in at least two of the following areas: qualitative impairment in social interaction; qualitative impairment in communication; and restricted, repetitive, and stereotyped patterns of behavior. This last criteria is the same as in Autism.
The final new Autism-related disorder added under the Pervasive Developmental Disorders section of DSM-IV is Asperger's Disorder. For this diagnosis to be made, there must be qualitative impairment in social interaction as manifested by at least 2 of the following: marked impairment in the use of multiple nonverbal behaviors (e.g., eye contact, gestures); failure to develop age appropriate peer relationships; lack of spontaneous seeking to share interests, or achievements with others; lack of social or emotional reciprocity; restricted repetitive and stereotyped patterns of behaviors, interests, and activities as manifested by at least 1 of the following: preoccupation with at least one stereotyped and restricted patterns of interest to an abnormal degree; inflexible adherence to nonfunctional routines or rituals; stereotyped and repetitive motor mannerisms; and preoccupation with parts of objects. There must additionally be clinically significant impairment in social, occupational or other functioning; and no clinically significant delay in language, cognitive development, adaptive behavior, or in curiosity about the environment. Asperger's Disorder is the diagnosis which will likely be made for persons who have traditionally been labeled as having "High Functioning Autism." It is the appropriate diagnosis for individuals who have evidence of many Autistic-like symptoms but for whom there are no language impairments.
The reasons for tightening the criteria for Autism and for adding Rett's Disorder, Childhood Disintegrative Disorder, and Asperger's Disorder to DSM-IV is to recognize that Autism is a disorder with many possible symptom variants. Because of this, individuals diagnosed with Autism in the past have been heterogeneous. This has made it difficult to conduct research to determine the etiology, prognosis, and appropriate treatment for individuals with Autism. Hopefully, as the DSM system recognizes the variability of Autistic-like behaviors across individuals, researchers can determine the etiologies and treatments for each of these related disorders. One question that remains unanswered due to this refinement in the DSM system is how the schools will recognize the need for services for individuals in all four of these diagnostic categories, not just for those diagnosed with Autism. Currently under PL 94-142, individuals with Autism must have services provided for them by the schools. However, individuals with Pervasive Developmental Disorder (PDD), the category that used to cover Asperger's Disorder-like symptoms and atypical Autism in DSM-IIIR, often had difficulty receiving services through the schools. Hopefully, the push for more homogeneity in individuals with Autism and Autism-related disorders like Rett's Disorder, Childhood Disintegrative Disorder, and Asperger's Disorder, will not result in some individuals losing out in much needed interventions.