Autism—commonly referred to as ASD, which stands for autism spectrum disorder—is the term used to address a collective group of disorders related to brain development that affect the behavioral skills of the sufferer. Autism is often addressed as a neurodevelopmental disorder in which neurological causes related to the brain lead to developmental disabilities in terms of social, behavioral, and communication skills.


This brain development disorder is characterized by repetitive behavior, difficulty in nonverbal and verbal communication, and inability to carry out social interactions along with normal leisure as well as play activities, all or some of which are observed at varying degrees in different patients.


The signs and symptoms of autism are observed more frequently in children, especially those between 2 and 3 years of age.



Types and categories of autism

ASD comprises a spectrum of disorders and thus is categorized in the following subtypes:


  • Autistic Disorder

This category of autism is often termed as “classic autism.” Those suffering from classic autistic disorder display considerable language delays, unusual interests as well as behavior, and challenges in communicating and interacting socially. Intellectual disability is also seen in many classic autistic cases.


  • Asperger Syndrome

Those suffering from Asperger syndrome display symptoms that are milder compared to autistic disorder. These patients encounter social challenges along with unusual interests and behavior, but they do not display intellectual disability or difficulties with language.


  • Pervasive Developmental Disorder – Not Otherwise Specified

This type is often abbreviated as PDD-NOS. Sufferers of this type display a few symptoms of autistic disorder or Asperger syndrome, but the patients may not display all symptoms. The symptoms are milder and they are fewer than that of autistic disorder, which causes major communication and social problems.


  • Childhood disintegrative disorder

This is a rare and severe disorder in which children develop normally and then, usually between the age of 2 and 4, lose their language, mental, and social skills along with experiencing seizure disorder.


Conditions similar to autism

Owing to similar symptoms, a few disorders can be found that are similar to autism spectrum disorder even though they are not the same. These conditions include:

  • Specific developmental disorder—in this condition the language disorder and other developmental disorders are similar to autism.
  • Intellectual disability—severe intellectual disability patients may behave similarly to autistic patients. Also, certain autistic patients might suffer from intellectual disability as well.
  • Schizophrenia—this condition, when developed in children, is often mistakenly considered to be autism.
  • Obsessive compulsive disorder (OCD)—symptoms of unusual and repetitive behavior might be similar in autistic and OCD patients, but OCD sufferers develop communication and social skills normally.
  • Selective mutism—in this condition, the child can speak in certain situations but is unable to speak and is mute in other situations.
  • Avoidant personality disorder—this condition is characterized by feelings of anxiety while having to deal with social situations, which is also seen in cases of autism.
  • Reactive attachment disorder—here a child suffers from a high degree of neglect and develops language and social skills only after receiving attention and love.


These are conditions that are thought to be autism as the symptoms mimic the disorder but are in fact different.