The way in which these disorders manifest themselves varies greatly from one child to another, hence the term “spectrum” or “continuum of disorders”, meaning that there are different ways in which the symptoms of this type of disorder appear and that the severity of these symptoms varies from case to case. The clinical picture is neither uniform nor absolutely demarcated, and its presentation ranges on a spectrum from more to less severe, varies over time, and is influenced by factors such as the degree of associated intellectual ability or access to specialized supports.
Individuals with ASD process information in their brains differently than others and develop at a different rate in each area. They are characterized by the presentation of clinically significant and persistent difficulties in social communication (marked difficulty in nonverbal and verbal communication used in interaction, absence of social reciprocity, and difficulties in developing and maintaining developmentally appropriate peer relationships), stereotyped motor or verbal behaviors, unusual sensory behaviors, excessive adherence to ritualistic routines and behavior patterns, and restricted interests.
The following criteria are proposed for the current diagnosis:
A. Persistent deficits in social communication and interaction in multiple contexts, manifested currently or in the past as follows:
1. deficits in social-emotional reciprocity.
2. Deficits in nonverbal communication behaviors used for social interactions.
3. Deficits in the development, establishment and understanding of relationships.
*Severity must be specified.
B. Restricted and repetitive repertoire of behaviors, interests, or activities, manifesting at least two of the following criteria currently or in the past:
1. stereotyped or repetitive motor movements, use of objects, or vocalization.
2. Insistence on monotony, inflexible attachment to routine, or ritualistic patterns of verbal or nonverbal behaviors.
3. Very restricted and fixed interests with an abnormal degree of intensity and focus.
4. Unusual reaction to sensory stimuli or unusual interest in sensory aspects of the environment.
*Severity should be specified.
C. Symptoms must be present from an early period of development (although they may not fully manifest until limited capacities no longer permit response to social demands, or be masked later by learned strategies).
D. Symptoms involve clinically significant impairments in social, occupational, or even other domains of functioning.
E. Intellectual disability (intellectual developmental disorder) or general developmental delay does not better justify these disorders.
It is also essential to specify the following points:
- Presence of intellectual impairment
- Presence of language impairment
- Associated with a known medical or genetic condition, or an environmental factor
- Associated with another neurodevelopmental, mental, or behavioral disorder
- Loss of acquired skills
- Paradigm shift
In recent years, with the publication of the DSM-V, there has been a very relevant change in the classification of this pathology. The DSM-IV established the section “Pervasive Developmental Disorders” which included 5 types:
- Autistic Disorder
- Rett’s Disorder
- Childhood disintegrative disorder
- Asperger’s Disorder
- Pervasive developmental disorder not specified
The DSM-V has created the term “Autism Spectrum Disorders” (ASD), itself included in the category “Neurodevelopmental Disorders”, which encompasses all of them with the exception of Rett’s Disorder, which is no longer part of this category. Instead of distinguishing between these subtypes, the DSM-V diagnostic definition specifies three levels of symptom severity, as well as the level of support needed, as developed above.