Research Reveals 90% of Autistic Adults Over 40 Remain Undiagnosed

A recent study from King’s College London has uncovered alarming data regarding autism diagnoses among older adults, revealing that 90% of autistic individuals over the age of 40 remain undiagnosed. This finding challenges the narrative that autism is a new or recently emerging condition, highlighting a significant gap in recognition and support for an often overlooked demographic.

The research, which focuses on autistic adults in midlife and older age, found that around 89% of those aged 40 to 59 and a staggering 97% of individuals over 60 lack a formal diagnosis. Lead author Dr. Gavin Stewart emphasized the implications of this underdiagnosis, stating, “These very high underdiagnosis estimates suggest that many autistic adults will have never been recognized as being autistic, and will have not been offered the right support.” This lack of acknowledgment can lead to increased risks for various health issues, including a four times higher risk of early dementia and a six times greater likelihood of suicidal ideation compared to their non-autistic peers.

The study highlights the urgent need for better understanding and recognition of autism in older populations. Autistic individuals have a life expectancy of approximately 75 years in the UK, six years shorter than that of non-autistic individuals who average 81 years. Older autistic adults also exhibit higher rates of serious health conditions, including cardiovascular disease, immune disorders, and gastrointestinal issues.

The findings are particularly striking in the context of the growing number of autism diagnoses in younger populations. Between 1998 and 2018, there was a remarkable 787% increase in autism spectrum disorder (ASD) diagnoses, predominantly among children and young adults. In contrast, older adults have not seen similar recognition despite the historical prevalence of the condition. The Centers for Disease Control and Prevention (CDC) reports that the rate of diagnosed autism among children has escalated from one in 150 in 2000 to one in 31 in 2020.

Historically, autism was often mischaracterized as “infantile autism,” limiting its recognition primarily to children and those with intellectual disabilities. Consequently, diagnostic criteria have evolved significantly since the 1980s, leading to increased awareness and recognition of the spectrum’s diversity. Despite this, many older adults remain unacknowledged in current statistics, leaving a critical gap in research and support.

Dr. Stewart pointed out that the high rates of underdiagnosis hinder the understanding of how autistic individuals age and complicate the provision of necessary services. For instance, a study conducted in the United States found that 35.1% of autistic adults aged 64 and older also had a diagnosis of dementia, compared to about 10% of the general population over 65. This discrepancy underlines the need for tailored healthcare solutions for older autistic individuals, who often encounter barriers to accessing appropriate support.

Social isolation poses another significant challenge, with around 20% of autistic adults over 40 reporting feelings of loneliness, a stark contrast to just 4% among their non-autistic peers. The study suggests that as autistic individuals age, they face unique challenges that require targeted interventions and support systems.

In light of these findings, Francesca Happé, Professor of Cognitive Neuroscience at King’s College London, emphasized the necessity for a comprehensive understanding of the aging autistic population. “Understanding the needs of autistic people as they age is a pressing global public health concern,” she stated. “We must adopt a lifespan approach that funds long-term research, integrates tailored healthcare, and expands social supports so that aging autistic people can live happy and healthy lives.”

This research, published in the Annual Review of Developmental Psychology, serves as a critical reminder that discussions around an “autism epidemic” often overlook the significant number of older adults who have never received a diagnosis. As awareness continues to grow, it is essential that healthcare systems adapt to include this largely invisible population in their strategies and services.