Other Conditions With Symptoms Similar to Autism

Autism and several other related disorders are grouped under the heading of autism spectrum disorders (ASDs), once known as pervasive developmental disorders (PDDs). These disorders all have similar symptoms.

Also, there are several medical conditions that can be confused with autism because of similar symptoms. Some of these medical conditions can occur along with autism but are not classified as ASDs. They include:

• Intellectual disability. People with severe intellectual disabilities may have many behaviors similar to those of autism but are not necessarily autistic. People who are autistic can also be intellectually disabled.
• Specific developmental disorders. Some developmental disorders, particularly language disorders, can mimic autism.
• Schizophrenia. When schizophrenia develops in childhood, which is rare, it can be confused with autism.
• Selective mutism. In selective mutism, a child is able to speak in some situations but unable to speak (is mute) in others.
• Obsessive-compulsive disorder (OCD). Some children with obsessive-compulsive disorder, like those with autism, have unusual interests and repetitive behaviors. But unlike children with autism, children with OCD are able to develop social and communication skills.
• Reactive attachment disorder. In this disorder, there is usually a history of severe neglect. Language and social skills usually begin to develop after a child is given love and attention.
• Avoidant personality disorder. This disorder is characterized by anxiety in dealing with social situations.

Specific diagnostic guidelines are used to distinguish autism from other conditions.^{footnote 1} Although other ASDs and certain medical conditions share some symptoms, they do not meet all of the diagnostic criteria for autism.