The primary difference between high and low functioning autism lies in the level of support an individual requires for daily living and the severity of their communication and social challenges.

Key distinctions include:

Communication Skills: Individuals with high functioning autism are often verbal and may have advanced language skills, though they might struggle with social nuances. In contrast, those with low functioning autism (often classified as level 3) typically have limited or no verbal speech and must rely on alternative communication methods like gestures or picture exchange systems.

Daily Living Independence: People with high functioning autism can often manage personal care and daily tasks with minimal support. Those with low functioning autism require substantial assistance for basic self-care, such as eating, dressing, or toileting.

Social Interaction: While individuals with high functioning autism may desire social connections but struggle to understand cues, those with low functioning autism often experience significant impairments and may show minimal engagement with others.

Behavioral Intensity: Low functioning autism is characterized by more intense, inflexible, and repetitive behaviors that can cause significant distress when routines are disrupted, whereas high functioning individuals may follow simpler routines with greater flexibility.