Autism Spectrum: in the Disorder

 

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Which Disorders Fall into the ASD?

    Asperger's syndrome, pervasive developmental disorder (PDD-NOS), Rett syndrome, and childhood disintegrative disorder all fall or have fallen within this broad spectrum (Blatt). A shift was made in 2013 when the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders) revised the previously separated diagnosis of autism spectrum disorder. The change caused all these disorders to instead fall under the umbrella term of ASD (Bohnsack, 2025).

    Asperger's syndrome is a neurobiological disorder that used to be acknowledged PDD-NOS. This includes mild autism-like symptoms. For example, this could be normal intelligence and learning development, but strange behaviors in social settings. Asperger's syndrome is three to four times more prevalent in males than in females. A diagnosis is usually present between the ages of 5 and 9. Asperger's syndrome falls under ASD due to the repetitive behavior patterns, difficulty with eye contact, poor control over fine motor skills, which in turn gives the appearance of clumsiness, and a special obsessive interest. Usually, the obsession shows up in the form of a want to only speak and learn about their specific object and/or subject of interest ("Asperger syndrome").

    PDD-NOS was a developmental disorder. This was used when a diagnosis was not specified, and the diagnosis is no longer used. In the past, this disorder also included autism-like symptoms such as Asperger's syndrome. These children had symptoms such as an avoidant gaze, lack of facial expressions, abnormalities in speech, obsessive and repetitive behaviors, and delay of motor skill development. Females were affected four times less than males. The main treatment of this disorder was behavioral therapy to help these symptoms ("Pervasive Developmental Disorder").

    Rett syndrome results in decreased motor function, severe intellectual disability, and autism-like behaviors. It is a continuous and rare neurological disorder now acknowledged as a pervasive developmental disorder (PDD). Rett syndrome occurs from an inherited sex-linked defect, but sporadic mutations within a gene named methyl CpG binding protein 2 (MECP2) are the majority of cases. The X chromosome is where MECP2 is located. In turn, this causes the syndrome to almost always affect girls. The rarity is one in every 15,000 females. Symptoms are reduced muscle tone, compulsive hand movements, failure of the head to grow as they age, decreased body weight, and increased levels of ammonia in the blood, also known as hyperammonemia ("Rett Syndrome").

    Childhood disintegrative disorder (CDD) is a rare neurobiological disorder in which the patient experiences a deterioration in social skills, language, and intellectual function within the first two years of their birth. This disorder is also now acknowledged as PDD. Males are more likely to be affected by CDD than females. Most often, symptoms of repetitive behavior patterns, delayed development of speech, bladder control, seizures, and bowel function occur at the ages of three and four. Nonetheless, sometimes symptoms may not be shown until the age of nine or ten. Treatment involves therapies that work on behavior, language skills, and communication (Rogers).

    Finally, it may be concluded that Asperger's syndrome, pervasive developmental disorder (PDD-NOS), Rett syndrome, and childhood disintegrative disorder are all a part of or were a part of the autism spectrum (Blatt).