Autism Spectrum Disorder: what it is, what its causes are and how to identify it

Around the clock the press speaks of this theme. Seven years ago, a weekly magazine spread the word: scientists would have discovered a way to diagnose autism without delay. Three characteristics of the new diagnostic model were evident: fast, cheap, technological.

No anamneses [1] : diagnosis in 10 minutes. No multidisciplinary teams : a radiologist. No traditional resources : a magnetic resonance imaging device.

Equipped with highly specialized knowledge in Biology, some researchers from the field of Medical Sciences, often working together with Psychologists, Linguists, Educators, and supported by Physicists and Mathematicians, develop software capable of measuring micro and macrostructural characteristics of brain tissues.

The software encodes this information. The encoding results in images. Through them one has an accurate view of the bundles of neuronal fibers that connect the brain regions. Images of these bundles in brains of people with typical and atypical development are compared. The type of diffusion of water molecules in brain tissues also constitutes information. With them one can find associations between the brain measurements [2] and the typical or atypical development profiles of several individuals.

How many people, having read the news, can identify the authors of the study, locate the publication and read the article in the language in which it was published, with full capacity to gauge its scientific value?

How to judge the information? Is she trustworthy? Does it make a useful contribution to parents and educators, educated, but without high-level scientific training? And from 2010 to here, year of publication of the article, the findings published in it were confirmed by other researchers in other research centers with brain imaging?

On the other hand, would there be ways of early identification of autism? What would they be? Are there risk factors?

Let’s do it by steps.

The official scientific description of autism

At the time of the study, the DSM 5 – Diagnostic and Statistical Manual of Mental Disorders, American Psyquiatric Association – had not yet been published. His previous version was in effect. But ICD 10 was already public. ICD is the International Code of Diseases of the World Health Organization.

DSM V and ICD are the world references for diagnosis, description and classification of diseases. With the difference that DSM V refers only to disorders that affect mental health.

At that time autism was already identified and described. The general terms of this identification and description remain today. The current nomenclature describes it as Autism Spectrum Disorder. There is convergence between DSM V and ICD 10.

Depending on DSM V and ICD 10, the following can be said about autism in general:

  • The use of the term spectrum in the term describing it reflects a dimensional and integrated understanding of the disorder. Several aspects of biopsychic development, socio-behavioral, may be affected, giving this process of development an atypical trajectory .
  • In the course of this trajectory, mental, cognitive and socio-behavioral abilities and abilities can deviate from the typical pattern . The arrangement formed by the suit of skills and abilities whose evolution was compromised or diverted, including the intensity of these deviations, gives rise to diverse biopsychic and socio-behavioral profiles. Thus, autism can be classified into gradations and in its description it is necessary to explain other associated medical or genetic conditions.
  • In Autistic Spectrum Disorder, developmental disorders of certain abilities and abilities intertwine and negatively affect two major domains of life. On the one hand, oral communication . On the other hand, social interaction . In the first case, due to failures in the development of processes related to the production and reception of speech and its cognitive and / or mental supports such as attention, inhibitory control, and representation of the mental state of participants in social interaction. In the second case because behaviors, interests, and actions are restricted and are expressed in a repetitive and / or stereotyped way.
  • Gravity is defined by the level of support required in terms of commitment in the field of communication and social interaction: it requires support, requires substantial support, and requires very substantial support.

A biomarker for autism?

In the first place, it should be reported that the news with which we started this article exaggerated the findings of the scientific article on which it was based. The researchers reported results from a study in which, through brain imaging, they found, in neuronal fibers that connect regions already recognized as involved in language, emotion and social cognition, differences between autistic and non-autistic patients. They concluded that the study opens promising avenues for the use of imaging in the diagnosis of autism.

There would then be a biological marker for autism: the observable differences in the bundles of neuronal fibers that connect areas of the brain involved in language, emotions and social cognition.

A study published four years later, in the year 2016, reviewed all findings from major studies comparing brain imaging of autistic and non-autistic individuals. Conclusion? The knowledge generated has been improved, continues to be promising and has confirmed the evidence of the neurobiological origin of autism, that is, there is a growing body of evidence that the origin of autism is linked to brain development. However, an uncontroversial biological marker has not yet been definitively established.

In February 2017, this is evidence of the advance, another important and numerous team of scientists, in a study published in the journal Nature – which together with the journal Science forms the pair of publications with the highest scientific prestige and reputation in the world – presented the following Evidences: children who at 24 months show typical autistic social behaviors, present in the first and second years of life, intracranial brain volume growth and hyperexpansion of the cerebral cortex thickness. Most of these studies used brain imaging obtained by functional magnetic resonance imaging techniques.

Behavioral Identifiers

Autism, we have seen, affects domains of communication and social interaction. In the human being, communication and social interaction are only fully and definitely functional at the end of childhood, and after adolescence. Thus, during the initial period of development, it is not easy to detect behaviors in which failures or deviations of patterns of linguistic communication and social interaction are evident. This detection is done, more often than not, in a clinical setting, by a specialized professional. It depends heavily on the existence of test batteries for assessing behaviors associated with autism. These tests need to undergo rigorous validation studies to be used. In Brazil we already have some. But there is no test that diagnoses autism.  Test batteries are instruments that help to compose the diagnosis. It requires extensive and thorough multidisciplinary teamwork.

Faced with the absence of a biologically definable and scientifically incontrovertible marker and information regarding behavioral signs, it is natural for educators and parents to seek information that enables them to detect these signs early in the course of development for the purpose of preventive monitoring. There has also been progress in this field. Even if the advancement of knowledge has not gained a speed that responds to the urgency with which we need it

After all, what are the causes of autism?

A conclusion is reached on this, supported by scientific evidence that gradually consolidates and forges a consensus: the disturbances of communication and social interaction, typical in Autism Spectrum Disorder, would have a neurobiological origin and would be associated with genetic and environmental factors .

There are also those who attribute the cause to the hypothesis of the absence of a “theory of mind” in autistics. This means that in autism there would be an inability to represent the mental states of other people. But the hypothesis does not have great scientific penetration. Although it is defended by an eminent and respected researcher in Cognitive Science: Uta Frith.

There are risk factors associated with autism. Some are environmental . For them a growing concern is the high variability of prevalence rates. Many scientific efforts are now being made to understand why such high prevalence rates of autism are found, for example, in some places such as South Korea.

There are also associated genetic factors. Recent studies account for the discovery of several genes involved in the controls of neuronal development. And we saw how there is evidence that disorders of neurobiological development are linked to the emergence of behaviors that characterize autistic behaviors.

To complete

It is seen that DSM V and ICD 10 standardize the description and provide criteria for identifying the mental health condition by identifying it as Autism Spectrum Disorder.

It is also seen that it mainly affects communication and social interaction and, thus, damages social functioning. The implications for the provision of education and health support are serious and weighty.

There is no consolidated data on prevalence in Brazil. In any case, if it is compatible with the world average, it will mean a huge contingent of affected people.

Autistic Spectrum Disorder involves a very diverse range of situations and conditions, probably of neurobiological origin, whose identification can only be made adequately by a multiprofessional team involving physician and psychologist at a minimum.


1- In Science, the word of a genius, isolated, is worth less than the consensus that is constituted in the field of studies, by the accumulation of evidence produced by several scientists, in several laboratories or different environments.

2 – Scientific information circulating in non-specialized journals and newspapers should be given little or no importance .

3 – It is important to have a reference for educational and health information . This person should be of your trust and have high scientific background.

4 – The worst approaches to autism are those that give parents and educators the opportunity to make informal observations to estimate the likelihood of autism in their students and / or children.

5 – No informal list of signs to watch is useful for parents or children.

6 – The best thing to do is to take care that there is:

  • good prenatal follow-up of the pregnant woman and the future baby.
  • Constant consultations with the pediatrician after birth and throughout childhood.
  • Clarified dialogue with the pediatrician to expand information on the development process of the baby in all aspects of its development, including those related to oral communication and social interaction .
  • Intense social-family interaction with the baby , especially in linguistic terms, from birth.
  • Privileged participation of the mother in providing food, organizing sleep and child hygiene. Talking with the child is never too much .
  • A quest to report to the pediatrician any observations that are in doubt .

[1] Anamnesis: make mention of a. From the Greek ana- “ backward”, by extension, “from the past”, +  mimneskesthai “remember” memory, remembrance. 

[2] Comparison of images of brain regions of autistic and non-autistic individuals would have revealed different patterns. This difference could be a way of distinguishing autistic children from non-autistic children through brain imaging.