In 2013, the release of the American Psychiatric Association’s DSM-5 combined these separate labels into the single, umbrella diagnosis of Autism Spectrum Disorder (ASD)

Before 2013, several conditions were diagnosed separately:

Asperger Syndrome:

• Average or above-average intelligence
• No significant language delay
• Difficulties with social communication

Autistic Disorder:

• More pronounced social, communication, and behavioral differences

Pervasive Developmental Disorder–Not Otherwise Specified

• Symptoms that did not fully fit other categories

Childhood Disintegrative Disorder

• Rare condition involving loss of previously acquired skills

These diagnoses are now generally included under ASD.

Autism is now diagnosed under a single condition called Autism Spectrum Disorder (ASD). Instead of separate “types,” doctors describe autism as a spectrum because people can have different strengths, challenges, and support needs.

Current Classification is based on Levels of Support. Under this system, ASD is often categorized into three levels:

Level 1 (Requires Support)

• Difficulties with social interactions
• May struggle with organization and flexibility
• Can often live independently with some support

Level 2 (Requires Substantial Support)

• More noticeable communication and social challenges
• Repetitive behaviors are more evident
• Needs significant support in daily life
• Atypical social behavior, like walking away mid-conversation
• High interest in specific topics
• Noticeable distress when faced with change
• May need school accommodations like reading help or social skills support

Level 3 (Requires Very Substantial Support)

• Severe difficulties with communication and social interaction
• Strong need for routines
• Severe communication deficits, such as being nonspeaking
• Repetitive behaviors like rocking or spinning
• Extreme distress when asked to switch tasks
• May need one-on-one time with an education assistant and may use augmentative and alternative communication (AAC) tools, such as picture symbols
• Requires extensive support for daily activities

Common Features of Autism

People with autism may experience:

• Differences in social communication
• Repetitive behaviors or interests
• Sensory sensitivities (sound, light, touch, taste, etc.)
• Strong preferences for routines and predictability
• Unique strengths, such as attention to detail, memory, creativity, or deep knowledge in specific interests.