Autism Spectrum Disorder
What is autism spectrum disorders (ASD)?
Autism spectrum disorders (ASD) are a group of neurodevelopmental conditions characterized by social and communication deficits and repetitive behaviours. Autism is seen as a spectrum, with symptoms that can range from very mild to severe. The World Health Organization (WHO) estimates the international prevalence of ASD at 0.76%; however, this only accounts for approximately 16% of the global child population. ASD is also more common in males; with the risk being 3–4-times higher in boys than in girls.
What are the signs of autism spectrum disorders ?
There are no reliable biomarkers for ASD, the diagnosis must be made based on observed behaviour. The Diagnostic and Statistical Manual of Mental Disorders (DSM) provides specific criteria for diagnosis and helps healthcare professionals.
Although individuals with ASD are very different from one another, the disorder manifests similarly in two key areas: social communication and sensory–motor behaviours.
Signs of ASD include:
- Delayed speech or communication difficulties
- Poor eye contact
- Lack of joint attention (not looking in the same direction as others)
- Limited interest in other people
- Repetitive movements (such as rocking, spinning, or hand flapping)
- Activities that could cause self-harm (such as biting or head-banging)
- Problems with coordination or odd movement patterns (such as clumsiness or walking on toes)
- Using few or no gestures by 12 months of age (for example, not waving goodbye)
- Not responding to name by 9 months of age
- Lack of facial expressions, such as showing happiness, sadness, anger, or surprise, by 9 months of age
What are the different types of autism spectrum disorders ?
There are 3 major types of ASD:
I. High-level or level 1 autism, previously known as Asperger's syndrome (a term no longer used by health professionals), is classified as a mild form of autism without intellectual disability. The main symptoms are impaired social interaction and restricted, stereotyped and repetitive interests and activities.
They may have difficulties socially connecting with others and struggle to grasp social settings in terms of communication such as body language, facial expressions, gestures, humor, and sarcasm.
II. Childhood disintegrative disorder (CDD), a rare condition that is typically observed after the age of three. It is one of the most severe parts of the spectrum. Due to its late onset, there will be a loss of previously gained skills in social, verbal, and motor (related to movement) functioning of the child. The child may lose abilities like movement, social and receptive skills.
III. Kanner’s syndrome, or infantile autism, occurs in early childhood and is a severe form of autism. The first symptoms appear before the age of three. The affected child may not make eye contact, smile, or point to objects, often experiencing significant communication difficulties and engaging in repetitive behaviors. Infantile autism causes sleep and eating disorders, temper tantrums, phobias, and aggression directed at self or others.
What conditions are associated with autism spectrum disorders?
- Irritability, aggression and self-injurious behaviors: Autistic individuals often experience elevated levels of irritability (temper tantrums, frustration or angry outbursts) and problem behaviors (physical aggression toward others).
- Attention Deficit Hyperactivity Disorder (ADHD), characterized as a neurodevelopmental disorder manifested by core symptoms of distractibility and impulsivity, either with or without hyperactivity.
- Anxiety disorders that differ from what is considered to be age-related normal anxiety or fear as they cause significant distress, are functionally impairing, are excessive for the situation, or persist beyond developmentally appropriate periods.
- Obsessive Compulsive Disorder (OCD), characterized by a pattern of obsessive thoughts and compulsive behaviors that interfere with daily activities and cause significant distress.
What are risk factors and causes of autism spectrum disorders?
ASD is a neurobiological disorder influenced by both genetic and environmental factors that impact brain development. Prenatal exposure to thalidomide and valproic acid have been reported to increase risk, while studies suggest that prenatal supplements of folic acid in patients exposed to antiepileptic drugs may reduce risk. Advanced maternal and paternal age have also both been shown to have an increased risk of having a child with ASD. However, there is no evidence linking vaccines, thimerosal, or mercury to ASD . Research continues to reveal factors that correlate with ASD risk, but no causal determinations have been made.
What treatments are available for autism spectrum disorders?
There is currently no standardized one-size-fits-all treatment for autism spectrum disorders. However, there are many ways to help minimize the symptoms and improve abilities. These approaches involve families, clinical practitioners, and educators:
Behavioral therapy
Educational and behavioral interventions play a central role in addressing communication, social skills, play, daily living competencies, academic skills, and inappropriate behavior. TEACCH (Treatment and Education of Autistic and related Communication-Handicapped Children) is commonly used for early intervention.
Pharmacological and dietary interventions
The most commonly prescribed drugs for individuals with ASD are aripiprazole, and risperidone, an atypical antipsychotic. Vitamin supplementation is also necessary, as deficiencies are observed in ASD.
Physical therapy and social skills training
These include activities and exercises that build motor skills and improve strength, posture, and balance. It also teaches children the skills they need to interact with others.
Sources:
- American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Washington DC: American Psychiatric Association; 1994.
- Baxter AJ, Brugha TS, Erskine HE, et al. The epidemiology and global burden of autism spectrum disorders. Psychol Med 2015;45:601-13
- Demily C, Poisson A, Peyroux E, et al. Autism spectrum disorder associated with 49,XYYYY: case report and review of the literature. BMC Med Genet 2017;18:9.
- Lord C, Brugha TS, Charman T, Cusack J, Dumas G, Frazier T, Jones EJH, Jones RM, Pickles A, State MW, Taylor JL, Veenstra-VanderWeele J. Autism spectrum disorder. Nat Rev Dis Primers. 2020 Jan 16;6(1):5. doi: 10.1038/s41572-019-0138-4. PMID: 31949163; PMCID: PMC8900942.
- Hodges H, Fealko C, Soares N. Autism spectrum disorder: definition, epidemiology, causes, and clinical evaluation. Transl Pediatr. 2020 Feb;9(Suppl 1):S55-S65. doi: 10.21037/tp.2019.09.09. PMID: 32206584; PMCID: PMC7082249.
- Genovese A, Butler MG. The Autism Spectrum: Behavioral, Psychiatric and Genetic Associations. Genes (Basel). 2023 Mar 9;14(3):677. doi: 10.3390/genes14030677. PMID: 36980949; PMCID: PMC10048473.
- Chaste P, Leboyer M. Autism risk factors: genes, environment, and gene-environment interactions. Dialogues Clin Neurosci. 2012 Sep;14(3):281-92. doi: 10.31887/DCNS.2012.14.3/pchaste. PMID: 23226953; PMCID: PMC3513682.
- Baird G, Cass H, Slonims V. Diagnosis of autism. BMJ. 2003 Aug 30;327(7413):488-93. doi: 10.1136/bmj.327.7413.488. PMID: 12946972; PMCID: PMC188387.
Published 2 Aug 2018 • Updated 19 Sep 2024
