Autism spectrum disorder (ASD) refers to differences or challenges in social interaction and communication, restricted interests, and repetitive behaviors, and is often accompanied by sensory processing disorder (sometimes referred to as sensory integration disorder).
The autism spectrum has a very wide range, from those with very mild characteristics to those that are profoundly affected.
Currently, the DSM-5 notes three levels of autism. Keep in mind that individuals can shift between levels of functioning and display different strengths and weaknesses, but these levels can be helpful when determining what interventions are appropriate.