What is Autism?

    According to current classification systems autism and autism spectrum disorders (ASD) are developmental disorders behaviourally defined through qualitative impairments in social and communicative development and restricted behaviours, interests and activities (DSM-5, American Psychiatric Association, 2013). This lifelong developmental disorder is currently thought to have a neurobiological basis and a strong genetic component.

    Autism is considered a spectrum: ranging from individuals with less peculiarities in their behavior and experiences (i.e. severity level 1 – previously described and distinguished into individuals with high-functioning autism and Asperger syndrome) to more severely affected individuals (i.e. severity level 3 – previously described as Kanner autism, infantile autism, childhood autism or low-functioning autism). Current diagnostic criteria specify whether ASD occurs with or without accompanying intellectual and language impairments. Symptoms must be present in early developmental periods and cause clinically significant impairment in social and/or occupational functioning. ASD may be detected by a qualified clinician in children as young as 18 months, and can be reliably diagnosed at around 30 months (Gillberg et al., 1996). Early signs of the disorder, such as deficits in eye contact, may already be present in the first year of life (Jones & Klein, 2013). In recent years the importance of early diagnosis and intervention has been highlighted through the availability of early diagnostic tools, such as the M-Chat (Modified Checklist for Autism in Toddlers) or the CARS (Childhood Autism Rating Scale) as well as checklists for parents provided by autism organisations (e.g. Autism Speaks or Autism e.V.).

    In the social communication and interactions domain specific peculiarities present as deficits in social-emotional reciprocity (e.g. there is not necessarily a normally regulated back-and-forth conversation; emotion or affect can be shown differently or shared in another way; initiation or response to social interactions can fail). In communication there is a higher focus on immediacy and less on contents mediated by idioms. There can also be fewer nonverbal communication (e.g. less or no eye contact and body language or limitations in understanding and using gestures and facial expressions). In addition individuals with ASD can exhibit difficulties in developing, maintaining and understanding relationships (e.g. when it comes to participating in imaginary play or adjusting behaviour to suit various social contexts). Further, there may be difficulties with making friends or a seemingly general absence of interest in peers.

    In the domain of restricted patterns of behaviour, interests and activities, specific features include stereotyped motor movements, use of objects or speech (e.g. motor stereotypies; lining up toys or flipping objects; echolalia; idiosyncratic phrases). Furthermore there can be a desire for insistence on sameness or ritualized patterns of behaviour (e.g. need to take the same route or eat the same food every day) together with highly restricted, fixated interests that are unusual in intensity and focus (e.g. strong attachment to unusual objects; excessively circumscribed interests). There is also hyper- or hyporeactivity to sensory input (e.g. apparent indifference to pain/temperature; adverse response to specific sounds and textures) and unusual interests in sensory aspects of the environment (e.g. excessive smelling or touching of objects; visual fascination with lights or movements).


    • American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Washington, DC: Author.
    • Gillberg, C, Nordin, V, & Ehlers, S. (1996). Early detection of autism. Diagnostic instruments for clinicians. European Child & Adolescent Psychiatry, 5, 67-74.
    • Jones, W., & Klin, A. (2013). Attention to eyes is present but in decline in 2-6-month-old infants later diagnosed with autism. Nature, 504, 427-433.