The concept of autism has changed significantly in the last years, thanks to advances in research. The last version of the most important international classification of mental disorders, the Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5), recognises these advances and includes autism within the neurodevelopmental disorders, debunking the old concept of a Pervasive Developmental Disorder (PDD).
However, the other international classification of mental disorders, the International Statistical Classification of Diseases and Related Health Problems-10 (ICE-10), maintains the old classification. Neurodevelopmental disorders are a group of disorders that originate in the gestation period. They are characterised by deficiencies in development that result in limitations to specific areas or overall limitations on the personal, social, academic and working level, etc.
In addition, autism has come to be called Autism Spectrum Disorder (ASD), because it recognises the autistic symptoms shared by all individuals in a broad range of phenotypes. That is why the autism subtypes have disappeared (Rett syndrome, Asperger syndrome, childhood disintegrative disorder, pervasive developmental disorder-not otherwise specified).
In this classification, the basic characteristics of autism are considered to be: a development of social interaction and communication that is clearly abnormal or deficient, and a very restricted repertoire of activities and interests.
Below are the diagnostic criteria for autistic spectrum disorder according to the DSM-5 (APA, 2013).
A. Persistent deficits in social communication and social interaction across multiple contexts, as manifested by the following, currently or by history
A.1. Deficits in social-emotional reciprocity, for example:
- abnormal social approach
- failure of normal back-and-forth conversation
- reduced sharing of interests, emotions, or affect
- failure to initiate or respond to social interactions
A.2.Deficits in nonverbal communicative behaviours used for social interaction, for example:
- poorly integrated verbal and nonverbal communication
- abnormalities in eye contact and body language
- deficits in understanding and use of gestures
- a total lack of facial expressions and nonverbal communication
A.3. Deficits in developing, maintaining, and understand relationships, for example:
- difficulties adjusting behaviour to suit various social contexts
- difficulties in sharing imaginative play or in making friends
- absence of interest in peers
B. Restricted, repetitive patterns of behaviour, interests, or activities, as manifested by at least two of the following, currently or by history (examples are illustrative, not exhaustive):
B1. Stereotyped or repetitive motor movements, use of objects, or speech, for example:
- simple motor stereotypes
- lining up toys
- flipping objects
- idiosyncratic phrases
B2. Insistence on sameness, inflexible adherence to routines, or ritualized patterns of verbal or nonverbal behaviour, for example:
- extreme distress at small changes
- difficulties with transitions
- rigid thinking patterns
- greeting rituals
- need to take the same route or eat …same food every day.
B3. Highly restricted, fixated interests that are abnormal in intensity or focus, for example
- strong attachment to or preoccupation with unusual objects
- excessively circumscribed or perseverative interests
B4. Hyper- or hyporeactivity to sensory input or unusual interest in sensory aspects of the environment, for example:
- apparent indifference to pain/temperature
- adverse response to specific sounds or textures
- excessive smelling or touching of objects
- visual fascination with lights or movement
B. Symptoms must be present in the early developmental period (but may not become fully manifest until social demands exceed limited capacities, or may be masked by learned strategies in later life.
C. Symptoms cause clinically significant impairment in social, occupational, or other important areas of current functioning.
D. These disturbances are not better explained by intellectual disability or global developmental delay.
Intellectual disability and autism spectrum disorder frequently co-occur. To make comorbid diagnoses of autism spectrum disorder and intellectual disability, social communication should be below that expected for general developmental level.
Individuals with a well-established DSM-IV diagnosis of autistic disorder, Asperger’s disorder, or pervasive developmental disorder not otherwise specified should be given the diagnosis of autism spectrum disorder.
Likewise, individuals who have marked deficits in social communication, but whose symptoms do not otherwise meet criteria for autism spectrum disorder, should be evaluated for “social (pragmatic) communication disorder". The main difference with ASD is that social communication disorder does not fill diagnostic criteria B, so there is no observation of restrictive or repetitive patterns of behaviour, interests or activities...
Apart from the diagnostic criteria, it should be specified if:
- it is accompanied or not by intellectual impairment,
- it is accompanied or not by language impairment,
- it is associated with a known medical or genetic condition or environmental factor,
- it is associated with another neurodevelopmental, mental or behavioural disorder, with catatonia
Also, the level of severity should be specified:
Level 1: needs help
Level 2: needs significant help
Level 3: needs very significant help
If we analyse the content of these diagnostic criteria, we observe that, independently from the two basic symptoms, criteria is included regarding the beginning of symptoms (C), in such a way that it is possible to diagnose autistic spectrum disorder if criteria A and B are seen during early childhood. The reason for this inclusion of this time criterion is in order to differentiate between ASD that, by definition, appears very early, from childhood disintegrative disorder, which manifests after a normal period of appearance which is no less than 2 years of age.