Autism spectrum disorder has a diverse group of conditions and can be categorized into 5 types.

Autistic disorder
Autistic Disorder is also known as classic autism. It is characterized by significant impairments in social interaction, communication, and the presence of repetitive behavior (speech) or interests. They are also overwhelmed by social and other stimulation.

According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), individuals with autism may have difficulties in understanding and responding to social cues, forming relationships, and may exhibit a preference for routine and sameness. The American Psychiatric Association defines it as one of the core types of autism spectrum disorder (ASD).

Asperger’s syndrome

Asperger’s syndrome is a sub type of autism spectrum disorder characterized by difficulties in social interaction and nonverbal communication, along with restricted and repetitive patterns of behavior and interests. Unlike classic autism, individuals with Asperger’s syndrome typically have average to above-average intelligence and language development. Common features may include intense focus on specific interests, difficulty understanding social norms, and challenges in interpreting nonverbal cues such as facial expressions or gestures. A point to note is that there is no significant delay in language or cognitive development.

Rett syndrome

Rett syndrome is a rare genetic disorder primarily affecting females, characterized by a regression of developmental abilities, including loss of speech and motor skills.

Typically, infants with Rett syndrome initially develop in line with expectations for the first six months of life. However, thereafter, they experience a regression, losing previously acquired skills such as crawling, walking, communication, and manual dexterity.

As the condition progresses, children with Rett syndrome may encounter escalating difficulties with muscle control, coordination, and communication. Seizures and intellectual disabilities are also common manifestations of the disorder. Although most of the time Rett Syndrome is caused by a gene mutation, it is rarely inherited.

Childhood disintegrated disorder

Childhood disintegrative disorder (CDD) is another rare kind of Autism, where a significant loss of previously acquired skills, such as language, social, and motor skills occur. This condition typically affects children between ages 2 and 10. Symptoms may include, but are not limited to,  rapid and severe decline in functioning, repetitive behaviors, social withdrawal, and difficulties with communication and adaptive behaviors.

Pervasive Developmental disorder/ PDD NOS ( Pervasive developmental disorder not otherwise specified )

When symptoms of the individual are not corresponding to any other specific disorder of ASD, then we term it as PDD NOS. Many children with PDD NOS may be too social. This diagnosis is made when the individual is suffering from some but not all symptoms or has relatively mild symptoms.

This is also called Threshold Autism. Individuals suffering from this have trouble in communication, play and interaction