Autism Spectrum Disorder is a developmental condition that affects how individuals communicate, interact, and experience the world around them. The DSM-5-TR defines three autism severity levels which describe support needs, not intelligence or potential. Clinicians rate the level of support a person needs in two areas, social communication and restricted or repetitive behaviors, ranging from level 1 (requiring support) to level 3 (requiring very substantial support).1
The levels of autism are not static, and they are not progressive stages. Support needs can change with time and development. Even so, the defined levels provide a helpful framework for understanding autism presentations and support needs.
Level 1 autism (mild): requiring support.
At level 1, individuals may not need intensive assistance, but they still experience challenges with social communication, flexibility, and organization. They might struggle to initiate conversations, understand unspoken social rules, or shift between topics appropriately. Misinterpreting sarcasm, tone, or facial expressions is common.
Treatment at this level is typically provided on an outpatient basis and may include social skills training, speech-language therapy, behavioral interventions, and occupational therapy. Cognitive-behavioral therapy (CBT) can also be helpful for addressing anxiety and building coping skills.
Level 2 autism (moderate): requiring substantial support and structure.
People with level 2 autism demonstrate more obvious challenges with communication and behavior that can affect daily life. Verbal communication may be limited or idiosyncratic, and some individuals rely heavily on scripting, echolalia (repeating words or phrases), or visual supports to communicate. Conversations may be one-sided or difficult to initiate and sustain, and nonverbal cues such as eye contact, gestures, and facial expressions are often limited or absent.
Social interaction at this level is often restricted to familiar caregivers or structured environments. Individuals may struggle to understand shared interests or emotional reciprocity, making peer relationships difficult to form or maintain. Social anxiety or frustration may escalate quickly, particularly when routines are interrupted or expectations are unclear.
Level 2 individuals typically engage in more frequent and noticeable repetitive behaviors. These may include hand-flapping, rocking, vocalizations, or intense fixation on specific topics. Sensory sensitivities, such as aversion to loud noises, textures, or lights, are also more pronounced and may trigger autistic meltdowns or withdrawal.
Treatment at this level requires a more intensive, structured approach. Most individuals benefit from an interdisciplinary team that includes speech therapists, occupational therapists, behavioral specialists, and physicians. Applied Behavior Analysis (ABA) or other evidence-based behavioral therapies are often central to treatment, with interventions delivered more frequently or in longer sessions than at level 1. Educational accommodations, caregiver training, and access to mental health support can also help progress.
Level 3 autism (severe): requiring very substantial support and around-the-clock care.
Level 3 is the most intensive classification of autism, reserved for individuals who face the greatest challenges in both communication and behavior. Many individuals with severe autism are nonverbal or use very limited verbal language. They may rely on augmentative and alternative communication (AAC) tools such as picture exchange systems, communication devices, or sign language to express their needs and preferences.
Social interaction is extremely limited. Some individuals may appear unresponsive to others or uninterested in social engagement. Others may want to connect but are unable to do so effectively due to cognitive, sensory, or communication barriers. Even with frequent prompting or support, reciprocal communication is often minimal.
Repetitive behaviors and restricted interests are more intense and may interfere with health and safety. These can include persistent self-injurious behaviors (such as head-banging or biting), aggressive outbursts, or complete shutdown in response to overstimulation. Sensory sensitivities are often extreme, and even small changes in environment or routine can lead to overwhelming distress.
Individuals at level 3 often require around-the-clock supervision and hands-on assistance with basic daily tasks such as bathing, dressing, eating, and toileting. While not recognized as a DSM level, the term “profound autism” was proposed by the 2021 Lancet Commission. The term was refined in a 2026 research consensus, referring to people with autism aged 8 and older who need an adult available around the clock for safety and who also have an IQ below 50, very limited spoken language, or both.2,3 In CDC surveillance data, 26.7% of autistic 8-year-olds met a simplified version of this definition, and these children were more likely than other autistic children to have self-injury and seizures.4 Because of the complexity of their needs, individuals with profound autism typically benefit from highly specialized, structured environments that are equipped to provide medical care alongside behavioral and therapeutic support.
Nonverbal autism: communication without words.
Studies of children with autism suggest that roughly 25% to 30% use little or no spoken language by school age.5,6 Those with autism who are nonverbal or minimally verbal do not use spoken language as a primary mode of communication or they use only a few words or phrases inconsistently. This is sometimes referred to informally as “nonverbal autism,” though it is not a separate diagnosis under the DSM-5-TR.
For many nonverbal individuals, behavior is a form of communication. What looks like “challenging behavior” is often a way of expressing a need, discomfort, or distress. Changes in behavior can also be a sign of an underlying medical issue, such as gastrointestinal pain or disrupted sleep. A large study of children and adolescents with autism found that aggression was associated with sleep and gastrointestinal problems,7 and a consensus report advises that problem behavior may be the main sign of a medical condition.8 Physician oversight can identify medical causes that behavioral assessments are not designed to detect.
Level 3 autism in adults and what continued care looks like.
Much of the conversation around severe autism focuses on children, but autism is a lifelong condition. Adults with level 3 autism face many of the same challenges as children, often compounded by aging caregivers, co-occurring medical conditions, and the move out of pediatric services.
Adults with level 3 autism continue to require structured environments, behavioral support, and often around-the-clock supervision. Many live in residential programs, group homes with high levels of staffing and behavioral expertise, or remain with aging family caregivers. Co-occurring conditions, including epilepsy, depression, and gastrointestinal disorders, may be more common in adulthood.9 These conditions call for inpatient adult autism treatment with medical and behavioral care coordinated by one team.
Evidence-based inpatient treatment for severe autism.
For children, adolescents, and young adults with level 2 or level 3 autism whose needs exceed what can be managed at home or in outpatient settings, the New Directions Program provides an inpatient treatment environment with medical and behavioral care in one setting.
Located in a hospital-based setting, the New Directions Program from Nexus Health Systems serves patients ages 6 and up with level 2 or level 3 autism, including those with co-occurring medical needs. With around-the-clock medical oversight, behavioral therapy, and rehabilitative care, the team delivers integrated treatment that addresses communication, sensory needs, safety, daily function, and long-term planning.
Each patient receives a customized treatment plan developed by an interdisciplinary team, including physicians, psychologists, Board-Certified Behavior Analysts, therapists, and nurses. The program is designed to stabilize immediate concerns and build skills that support adaptive growth, social development, and a safe transition back to home, school, or other supportive settings.
If you are supporting a child or young adult with autism who needs a higher level of care, reach out to our admissions team to learn more and determine next steps.
