Introduction

Diagnostic Criteria for Autism

The leading diagnostic guides for autism are the Diagnostic and Statistical Manual of Mental Disorders (DSM), published in print and electronically by the American Psychiatric Association, and the International Statistical Classification of Diseases and Related Health Problems (ICD) of the World Health Organization (WHO). The ICD offers more categories under the umbrella of autism.

Both diagnostic tools are clinical, philosophical, legal, and political. Courts throughout the world use the guidelines in these manuals to determine mental fitness, for example. The Americans with Disabilities Act (ADA) and the Individuals with Disabilities Education Act (IDEA) use the DSM to define some disabilities, including autism.

The more serious the symptoms, the more likely the individual is diagnosed with classical autism. Those with severe symptoms, but able to function with minimal assistance, are often categorized as high-functioning autistic. The least extreme cases, but likely the most common, are categorized as Asperger’s Syndrome or having a pervasive developmental disorder, not otherwise specified (PDD-NOS).

Potential Medical Classifications

Stella Waterhouse (1999) developed categories of autistic disorder based on possible causes. The definitions are not in wide use, possibly because the DSM and mental health professionals tend to be focused on symptoms. The Waterhouse autism categories are:

  • perceptual autism (linked to a damaged limbic system)
  • perceptual Asperger syndrome (linked to frontal lobe problem)
  • reactive autism (limbic system)
  • reactive Asperger syndrome (frontal lobe)
  • induced autism (limbic system)
  • induced Asperger syndrome (frontal lobe)
  • secondary autism (caused by accident or illness)

Until physical causes can be determined with confidence, symptomology will remain the primary diagnostic criteria for autism and other pervasive developmental disorders.

American Psychiatric Association

DSM-IV-TR Criteria for Autism

Autism Spectrum is diagnostic criteria 299.00 in the DSM-IV Revised, 2000.

  1. A total of six (or more) items from (A), (B), and (C), with at least two from (A), and one each from (B) and (C)
    1. qualitative impairment in social interaction, as manifested by at least two of the following:
      1. marked impairments in the use of multiple nonverbal behaviors such as eye-to-eye gaze, facial expression, body posture, 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 (note: in the description, it gives the following as examples: not actively participating in simple social play or games, preferring solitary activities, or involving others in activities only as tools or “mechanical” aids )
    2. qualitative impairments in communication as manifested by at least one of the following:
      1. 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)
      2. in individuals with adequate speech, marked impairment in the ability to initiate or sustain a conversation with others
      3. stereotyped and repetitive use of language or idiosyncratic language
      4. 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 two 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
  2. 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
    3. symbolic or imaginative play
  3. The disturbance is not better accounted for by Rett’s Disorder or Childhood Disintegrative Disorder

Asperger’s Syndrome

The DSM-IV does not include Asperger's Syndrome within the diagnostic matrix for autism, but both appear as developmental disorders. Diagnostic criteria for Asperger’s disorder according to DSM-IV-TR (American Psychiatric Association 2000):

  1. Qualitative impairment in social interaction, as manifested by at least two of the following:
    1. marked impairment in the use of multiple non-verbal 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.
  2. 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, non-functional 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.
  3. The disturbance causes clinically significant impairment in social, occupational, or other important areas of functioning.
  4. There is no clinically significant general delay in language (e.g. single words used by age two years, communicative phrases used by age three years.)
  5. 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.
  6. Criteria are not met for another specific Pervasive Developmental Disorder or Schizophrenia

World Health Organization

The ICD-10 Criteria for Autism

The International Statistical Classification of Diseases and Related Health Problems, Tenth Edition, 2006
[http://www.who.int/classifications/apps/icd/icd10online/ accessed 6 December 2006]

Note: The ICD uses “International English” for spelling and grammar.

F84: Pervasive developmental disorders: A group of disorders characterized by qualitative abnormalities in reciprocal social interactions and in patterns of communication, and by a restricted, stereotyped, repetitive repertoire of interests and activities. These qualitative abnormalities are a pervasive feature of the individual's functioning in all situations.

Use additional code, if desired, to identify any associated medical condition and mental retardation.

F84.0: Childhood autism: A type of pervasive developmental disorder that is defined by: (a) the presence of abnormal or impaired development that is manifest before the age of three years, and (b) the characteristic type of abnormal functioning in all the three areas of psychopathology: reciprocal social interaction, communication, and restricted, stereotyped, repetitive behaviour. In addition to these specific diagnostic features, a range of other nonspecific problems are common, such as phobias, sleeping and eating disturbances, temper tantrums, and (self-directed) aggression.

Autistic disorder; Infantile: autism or psychosis; Kanner’s syndrome;

Excludes: autistic psychopathy ( F84.5 )

F84.1: Atypical autism: A type of pervasive developmental disorder that differs from childhood autism either in age of onset or in failing to fulfill all three sets of diagnostic criteria. This subcategory should be used when there is abnormal and impaired development that is present only after age three years, and a lack of sufficient demonstrable abnormalities in one or two of the three areas of psychopathology required for the diagnosis of autism (namely, reciprocal social interactions, communication, and restricted, stereotyped, repetitive behaviour) in spite of characteristic abnormalities in the other area(s). Atypical autism arises most often in profoundly retarded individuals and in individuals with a severe specific developmental disorder of receptive language.

Atypical childhood psychosis; Mental retardation with autistic features

Use additional code (F70-F79), if desired, to identify mental retardation.

F84.2: Rett's syndrome: A condition, so far found only in girls, in which apparently normal early development is followed by partial or complete loss of speech and of skills in locomotion and use of hands, together with deceleration in head growth, usually with an onset between seven and 24 months of age. Loss of purposive hand movements, hand-wringing stereotypes, and hyperventilation are characteristic. Social and play development are arrested but social interest tends to be maintained. Trunk ataxia and apraxia start to develop by age four years and choreoathetoid movements frequently follow. Severe mental retardation almost invariably results.

F84.3: Other childhood disintegrative disorder: A type of pervasive developmental disorder that is defined by a period of entirely normal development before the onset of the disorder, followed by a definite loss of previously acquired skills in several areas of development over the course of a few months. Typically, this is accompanied by a general loss of interest in the environment, by stereotyped, repetitive motor mannerisms, and by autistic-like abnormalities in social interaction and communication. In some cases the disorder can be shown to be due to some associated encephalopathy but the diagnosis should be made on the behavioural features.

Dementia infantilis; Disintegrative psychosis; Heller's syndrome; Symbiotic psychosis

Use additional code, if desired, to identify any associated neurological condition.

Excludes: Rett's syndrome ( F84.2 )

F84.4: Overactive disorder associated with mental retardation and stereotyped movements: An ill-defined disorder of uncertain nosological validity. The category is designed to include a group of children with severe mental retardation (IQ below 35) who show major problems in hyperactivity and in attention, as well as stereotyped behaviours. They tend not to benefit from stimulant drugs (unlike those with an IQ in the normal range) and may exhibit a severe dysphoric reaction (sometimes with psychomotor retardation) when given stimulants. In adolescence, the overactivity tends to be replaced by underactivity (a pattern that is not usual in hyperkinetic children with normal intelligence). This syndrome is also often associated with a variety of developmental delays, either specific or global. The extent to which the behavioural pattern is a function of low IQ or of organic brain damage is not known.

F84.5: Asperger's syndrome: A disorder of uncertain nosological validity, characterized by the same type of qualitative abnormalities of reciprocal social interaction that typify autism, together with a restricted, stereotyped, repetitive repertoire of interests and activities. It differs from autism primarily in the fact that there is no general delay or retardation in language or in cognitive development. This disorder is often associated with marked clumsiness. There is a strong tendency for the abnormalities to persist into adolescence and adult life. Psychotic episodes occasionally occur in early adult life.

Autistic psychopathy; Schizoid disorder of childhood

F84.8: Other pervasive developmental disorders

F84.9: Pervasive developmental disorder, unspecified (PDD-NOS, not otherwise specified)

More on Asperger's Syndrome

Additional AS Criteria

Characteristics of Asperger’s syndrome as listed by Wing (1981), quoted in Bowler (2007):

  • More common in boys
  • Normal age of onset of speech
  • Impaired non-verbal communication
  • Flat intonation and absent or large, clumsy gestures
  • Impairment of two-way social interaction
  • Repetitive activities and resistance to change
  • Poor motor coordination
  • Clumsy, odd gait and posture
  • Circumscribed interests with good rote memory for facts on narrowly defined or unusual topics
  • Bullied at school because of perceived eccentricity

The Gillberg diagnostic criteria for Asperger’s syndrome (Gillberg 1991):

  1. Social impairment (extreme egocentricity) (at least two of the following):
    • difficulties interacting with peers
    • indifference to peer contacts
    • difficulties interpreting social cues
    • socially and emotionally inappropriate behavior.
  2. Narrow interest (at least one of the following):
    • exclusion of other activities
    • repetitive adherence
    • more rote than meaning.
  3. Compulsive need for introducing routines and interests (at least one of the following):
    • which affect the individual’s every aspect of everyday life
    • which affect others
  4. Speech and language peculiarities (at least three of the following):
    • delayed speech development
    • superficially perfect expressive language
    • formal pedantic language
    • odd prosody, peculiar voice characteristics
    • impairment of comprehension including misinterpretations of literal/implied meanings
  5. Non-verbal communication problems (at least one of the following):
    • limited use of gestures
    • clumsy/gauche body language
    • limited facial expression
    • peculiar, stiff gaze
  6. Motor clumsiness:
    • poor performance in neurodevelopmental test.

Testing for Asperger’s

Asperger’s scales and instruments used to evaluate children:

  • ASAS or Australian Scale for Asperger’s Syndrome (Garnett and Attwood 1998)
  • ASDI or Asperger’s Syndrome Diagnostic Interview (Gillberg et al 2001)
  • ASDS or Asperger Syndrome Diagnostic Scale (Myles, Bock and Simpson 2001)
  • ASSQ or Autism Spectrum Screening Questionnaire (Ehlers, Gillberg and Wing 1999)
  • CAST or Childhood Asperger Syndrome Test (Scott et al. 2002; Williams et al. 2005)
  • GADS or Gilliam Asperger Disorder Scale (Gilliam 2002)
  • KADI or Krug Asperger’s Disorder Index (Krug and Arick 2002)

Asperger’s scales and instruments used to evaluate adults:

  • ASQ or Autism Spectrum Quotient (Baron-Cohen e al. 2001b; Woodbury Smith et al. 2005)
  • EQ or Empathy Quotient (Baron-Cohen and Wheelwright 2004)
  • The Reading the Mind in the Eyes Test (Rutherford, Baron-Cohen and Wheelwright 2002)
  • FQ or Friendship Questionnaire (Baron-Cohen and Wheelwright 2003)
  • ASDASQ or Autism Spectrum Disorders in Adults Screening Questionnaire (Nylander and Gillberg 2001).