What Is Autism?

What is Autism

A thinking person’s guide to autism

The meaning of the word ‘autism’

Autism is a behavioural diagnosis of a disability. If a person behaves in certain ways within the categories of communication and social interaction, repetitive behaviours and restricted interests, a qualified professional can assign the label of autism.

At the present time there is nothing else to ‘autism’ itself apart from those symptoms. In other words a diagnosis of autism is based solely on surface symptoms. The observable symptoms and the diagnosis of autism do not reveal anything about how and why those symptoms arise.

Every individual and family can experience autism differently, with a different set of impairments and symptoms, varying in their severity and frequency.

Autism beyond the behavioural diagnosis

Promising research into ‘diagnostic biomarkers’ is being carried out at present. Diagnostic biomarkers would be concrete biological tests to diagnose a condition such as autism, as opposed to a mere observation of surface symptoms. These tests would measure substances, for example damaged proteins in the blood, or the presence or absence of specific microbes in the saliva.

Extensive research demonstrates that children and adults with autism suffer more medical problems, and have far more abnormal biological findings, than their typical peers.

The current diagnostic criteria for autism, or Autism Spectrum Disorder ASD, encompass what is believed to be a highly heterogeneous condition – in other words the autism-related symtoms and behaviours can have different causes in different individuals. Even though many individuals can be diagnosed with the same behavioural label, different causative factors and mechanism could be at play in each case.

“My intact thoughts don’t transmit reliably to my motor system. I want to speak but I cannot.”
(Ido Kendar, author, “In Two Worlds”)

What causes the symptoms of autism?

Current research points to autism-related symptoms and behaviours being the downstream symptoms of physiological causes, including those linked to abnormal sensory processing and impaired motor function.

Experts used to claim that autism was caused by poor, detached parenting. This view evolved to attribute autism to genetic causes, a lifelong and static condition.

The most recent findings, however, point to early environmental influences being at least as important as genetic risk factors predisposing a baby to develop autism (1, 2, 2b). In addition to this, many of the ‘autism susceptibility genes’ are the genes that predispose a baby to negative consequences of environmental factors, such as immune stressors (1, 2, 3, 4, 5) or environmental pollutants (1, 2).

Many of those ‘autism risk’ factors – both genetic and environmental – can influence the development and functioning of the brain in a way that makes it difficult for a person to process the information that is received by their senses (sounds, vision, smell, touch), and to control how their body reacts to its surroundings.

“Patients diagnosed with autism overreact to stimuli… which matches their sense of being overwhelmed by incoming data, and that they are unable to control cortical activity according to varying levels of uncertainty.

These results indicated that increased cortisol was associated with increased sensory sensitivity and enhanced stress.

sensory symptoms start demonstrating relationships with adaptive functioning and language proficiency in the early years.”
(Gesundheit & Rosenzweig 2017)

Is autism static and lifelong?

In the past it has been commonly assumed that the symptoms of autism, that is the autism itself, are hard-wired, static and lifelong. However the research findings from the last decade firmly demonstrate that ‘autism’ is in many cases a changing state.

Numerous studies now confirm that normally developing children can suddenly lose their developmental milestones and previously acquired language and social skills, and regress into autism. The reasons why this happens are largely unknown, as unfortunately regressions are rarely a subject of detailed clinical investigations.

Those children who lose their previously acquired skills and regress into autism comprise over a third of all autism cases. Furthermore, there are an increasing number of reports of unusual patterns of regression—including repeated regressions, regressions involving losses of gross motor function, and/or regressions after age three years (1, 2, 3, 4).

Some children and adults on the autism spectrum present with decreasing symptoms, or even complete recovery from core autism symptoms (remember that there is nothing to autism apart from symptoms) and subsequent removal of the diagnosis of autism.

In addition to several published studies (1, 2, 3, 4), there is now a growing number of adult individuals with autism who have shared their first-hand experiences of both worsening/regression, as well improvements/recovery from autism symptoms.

These findings challenge the assumption that autism is static and lifelong, and provide strong “evidence that recovering from autism is indeed possible and opens up the possibility of improvement, even without optimal normalization.” Such research also adds weight to the suggestion that autism is a plural, and a highly heterogeneous, condition.

“This implies that any developmental disconnection in our cohort of autistic men is more likely to be ‘a weakening’ rather than an irreversible ‘failure’ of connectivity per se.

In other words, the functional architecture of brain in ASD, though not measureable at baseline, was still in place and revealed by riluzole.”
(Ajram 2017)

What is a medical comorbidity and why is it relevant to autism?


When the term comorbidity was coined in 1970, it meant ‘a distinct additional clinical entity’. Since then, the word comorbidity has been used to mean simultaneous, but unrelated pathologies or disease processes. So, for example, many children and adults with a diagnosis of autism also suffer epilepsy. Many more suffer sublinical (invisible) seizures. Epilepsy would in the past be considered to be comorbid to autism but also unrelated in terms of pathology or causes.

However, a growing body of scientific evidence is showing that epilepsy and autism are intrinsically linked in pathology and, increasingly, are responsive to same or similar treatments. The same can be said about any of the metabolic, gastrointestinal, inflammatory and other comorbidities commonly found in people with autism. In fact, just as with epilepsy, there is growing research to indicate that these conditions do not necessarily exist independently of the autism, but rather can potentially cause the surface symptoms used to diagnose autism.

“…there is a pressing need for all clinicians to approach ASD as a chronic health condition requiring regular follow-up and routine screening and treatment of medical and psychiatric issues.”
(Davignon et al. 2018)

The importance of comorbidity in autism

Studies and clinical experience have shown that many individuals on the autistic spectrum have a range of health problems, often concerning the gut and immune systems, but involving other areas and body systems as well. As discussed above, these medical problems have sometimes been characterized as simply comorbid in all cases, that is, as existing entirely independently of the symptoms of autism (i.e. autism itself). However there is no firm basis to such assumptions.

Current clinical and research evidence shows that these health problems, often serious and chronic, as in the case of epilepsy, exacerbate or cause what we have chosen to call autism.

For a more thorough discussion of autism and medical comorbidites, read our publication ‘Medical Comorbidities in Autism Spectrum Disorder:  A Primer for Health Care Professionals and Policy Makers’.

Medical comorbidity and premature mortality in autism

Premature mortality is significantly increased in autism owing to a multitude of medical conditions. Early deaths are estimated to be three to ten times higher than the general population, with one large scale Swedish study establishing the average life expectancy of a person with severe autism as only 39.5 years. While mortality is higher across variety of medical conditions, the single most common cause of premature death in severe autism is epilepsy.

In contrast, the average life expectancy in individuals with high-functioning autism/Asperger syndrome was found by the Swedish study to be 58 years. While this is much higher than the life expectancy in severe autism, it is still considerably lower than life expectancy in the general population.

“Autism is what we call a mosaic disease, it has many different facets to it… if you look into the literature, you’ll find that autism isn’t just a sort of neuropsychiatric, behavioural, and social disorder… It is a systemic disease, but the most obvious effect is the social and behavioural, and so it tends to be associated with that… What we have to do now using our modern technology is to take a step back, look at the whole problem as a systemic problem, and see how all the abnormal interactions that are occurring in the different organ systems in the body might impact on brain development and to give us the symptoms of autism, which are becoming all too familiar.”
Prof J Nicholson, Chair In Biological Chemistry, Imperial College London

How can physical factors influence behaviours?

This is an extremely complex question; however, two brief examples will help illustrate the relationship between comorbidity and autism sympoms, or those commonly present in autism, such as anxiety, irritability or depression.

A very common biomedical problem found in many individuals with autism is a low-level pro-inflammatory state, including neuroinflammation (1, 2, 3, 4, 5). Inflammation can directly and negatively influence levels of hormones and/or neurotransmitters: causing heightened adrenergic/fear responses, fluctuations in levels of serotonin, and increased levels of glutamate (an excitatory neurotransmitter).

All of those physical changes can have negative consequences on behaviours, cognitive function, sensory processing abilities, capacity to react to surroundings and ability to communicate. The firm evidence for this effect comes not only from the stunning results of experimental animal studies, but also from the well known changes in behaviour and mental states in individuals undergoing interferon-alpha and similar treatments.

Another illustrative set of examples of the ability of biomedical factors to influence mental states and cause behavioural regression and loss of previously mastered skills in both children and adults comes from medical literature on long-term consequences of encephalitis. Autoimmune encephalitis has been observed to cause autistic regression in previously typically-developing children (1, 2, 3, 4).

In addition to autoimmune encephalitis, there are numerous recorded cases of viral and bacterial encephalitis (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) causing marked disturbances in personality and behaviours in both children and adults, including regression in language and social communication skills, emergence of repetitive actions, motor and sensory dysfunction, aggressive and self-harming behaviours, irritability and tantrums, anxiety, sleep disturbances, and abnormal EEG activity in the brain, which are all hallmarks of idiopathic, or ‘common’ autism.

Factor I (nonsocial behavior)

  • Rarely has eye to eye contact with others
  • Difficult to engage in social interaction
  • Emotional responses not appropriate
  • Has frequent temper tantrums/irritable
  • Rarely initiates activities or interaction
  • Rarely smiles
  • Responds minimally to social interaction
  • Does not seem to enjoy play activities

Factor 2 (apathetic behavior)

  • Is easily frustrated
  • Appears underactive/passive
  • Seems withdrawn
  • Very subdued or quiet
  • Is lethargic


Factor 3 (immature, poorly integrated behavior)

  • Does not respond to comforting when distressed
  • Is mainly interested in objects rather than people
  • Movements and activities appear random and disorganized

Factor4 (flaccid, self-stimulating behavior)

  • Leu objects fall out of hands as if they didn’t exist
  • Rocks head, body in a repetitive way
  • Seems tense and unrelaxed

Factor 5 (attentions- deficit)

  • Has difficulty remaining focused on a task
  • Has a short attention span
  • Additional severity scale items not included in factor scales
  • Shows a lack of social responsiveness
  • Is fussy and cranky for no apparent reason


Children were classified as encephalopathic if they exhibited one or more of the following criteria: (a) Loss or delays in the acquisition of developmental milestones. Availability of this evidence was contingent on the child having reached an age where these skills should have been established. Clear loss or delays in developmental milestones was sufficient basis to be classified as encephalopathic, but necessarily co-occurred with lowered developmental scores. Expressive speech, walking, and crawling are the developmental milestones that were emphasized in this classification. Loss of developmental milestones consisted of marked regression or disappearance of established speech and/or loco-motion skills.
From: ‘The Development of a Q-Sort Behavioral Rating Procedure for Pediatric HIV Patients‘ Moss et al. 1994 link

“Allergic conditions are easily treatable; however, ASD children may be under-diagnosed and/or undertreated for allergic and other common childhood diseases, in part due to their impaired communication skills. Practicing physicians should be aware of the potential impact of allergic diseases on behavioral symptoms and cognitive activity in ASD children”
(Jyonouchi et al. 2010)

“If the gastrointestinal disorder is recognized and medical treatment is effective, the problem behaviours may diminish. When abdominal pain or discomfort is a setting event, psychotropic medications are likely to be ineffective and may even aggravate the problem if they have adverse gastrointestinal effects.”
(Buie et al. 2010)