Autism Spectrum Disorder (ASD) is a complex neurodevelopmental condition characterized by persistent challenges in social communication, interaction, and restricted or repetitive behaviors. The question of how long individuals with ASD live is complex, often generating misunderstanding due to the vast range of support needs within the spectrum. This article provides evidence-based information regarding the longevity and associated health risks specifically for individuals diagnosed with severe autism.
Defining Severe Autism and Support Needs
Severe autism is clinically defined as Level 3, which signifies “requiring very substantial support.” Individuals in this category experience severe impairment in daily functioning due to pronounced deficits in verbal and nonverbal social communication skills. They exhibit very limited initiation of social interactions and often provide minimal response to social overtures from others.
Many individuals with Level 3 autism are non-verbal or use only a few words of intelligible speech, making it extremely difficult for them to communicate their internal state, pain, or medical symptoms. Their patterns of restricted, repetitive behaviors, fixed rituals, and extreme difficulty coping with change markedly interfere with functioning in all areas of life. This level of severity is frequently associated with co-occurring intellectual disability, which significantly increases the complexity of both support needs and health management.
Life Expectancy Data and Mortality Risks
Research consistently shows that individuals with severe autism, particularly those with a co-occurring intellectual disability, have a significantly reduced life expectancy compared to the general population. One large study found that individuals with both autism and intellectual disability had a mortality rate 2.83 times higher than those without these diagnoses. This increased mortality risk translates to a substantial reduction in lifespan, with estimates ranging up to a 30-year decrease compared to the general population.
The average age at death for individuals with autism spectrum disorder in some older studies was reported to be as low as 36 years. More recent data indicates that for men with autism and intellectual disability, life expectancy is reduced by over seven years, and for women with both diagnoses, the reduction can be nearly 15 years. A major contributing factor to this disparity is the alarmingly high rate of death from accidental injury.
Accidental deaths are a leading cause of diminished life expectancy, with individuals with autism being three times more likely to die from injuries than the general population. Specific causes of injury-related mortality are frequently suffocation, asphyxiation, and drowning. Children with autism are 160 times more likely to die from drowning than other children, often linked to the tendency for wandering or elopement. Additionally, sudden unexpected death, including sudden unexpected death in epilepsy (SUDEP), contributes to the higher mortality statistics.
Major Comorbidities That Impact Longevity
The reduced lifespan for individuals with severe autism is driven not by autism itself, but by the high prevalence of co-occurring medical and psychiatric conditions. Epilepsy and seizure disorders are highly prevalent in this population, affecting over 20% of those with co-occurring intellectual disability. The presence of comorbid epilepsy is a major negative prognostic indicator, and it is associated with a significantly higher mortality rate due to the risk of SUDEP.
Gastrointestinal (GI) issues are also extremely common, with prevalence estimates ranging from 46% to 84%. Chronic conditions such as constipation, chronic diarrhea, and gastroesophageal reflux disease (GERD) can cause persistent pain and discomfort. For individuals who are non-verbal, the inability to clearly communicate this internal pain can lead to misdiagnosis, chronic nutritional deficiencies, or behavioral changes that mask a severe medical problem.
Severe psychiatric comorbidities and behavioral challenges also impact longevity. Anxiety disorders are common and can contribute to chronic physiological stress, which may negatively affect long-term arterial health. Chronic health issues like sleep disorders, which affect an estimated 80% of individuals with ASD, further complicate overall health and contribute to daily challenges.
Improving Health Outcomes Through Targeted Support
Improving health outcomes for individuals with severe autism requires a proactive, multidisciplinary approach focused on early identification and management of comorbidities. Comprehensive medical monitoring is necessary, particularly for non-verbal individuals who cannot report symptoms of conditions like seizures or chronic pain. Coordinated care between specialists, including neurologists, gastroenterologists, and psychiatrists, is important to manage the complex interplay of co-occurring conditions.
Targeted interventions can mitigate the high risk of accidental death, which is a major driver of reduced life expectancy. Given the exceptionally high risk of drowning, swimming lessons are often considered a top-priority intervention for children diagnosed with autism. Specialized behavioral support is also helpful to address and manage challenging behaviors, such as self-injury and elopement, thereby reducing the risk of injury.
For individuals with limited verbal communication, ensuring access to Augmentative and Alternative Communication (AAC) aids is fundamental for promoting their ability to express needs, wants, and discomfort. Providing a structured and predictable environment can help reduce anxiety and frustration, which are often linked to challenging behaviors that can compromise safety. By addressing the underlying medical and systemic issues, it is possible to enhance the quality of life and potentially extend the lifespan for those with the highest support needs.