Many adults with autism go undiagnosed, as experts warn of overlooked symptoms

A growing number of adults in the United States may have autism spectrum disorder that went undiagnosed in childhood, experts say, with symptoms that are often overlooked or misunderstood.

The latest estimates link to a prevalence of about 1 in 36 children with autism in the United States, according to the Department of Health and Human Services, while roughly 1 in 45 adults are diagnosed with autism spectrum disorder, Autism Speaks reports. The New Jersey based nonprofit notes that many adults have not received a diagnosis or were misdiagnosed, highlighting a gap in recognition that persists even as advocacy grows. For adults who learn they are on the spectrum later in life, symptoms may have been present for years but were not recognized as part of autism. In daily life, masking — the effort to hide autistic traits to fit in — is common and can slow recognition of the condition.

Autism is defined by challenges with social communication and the presence of restricted or repetitive behaviors, according to the American Psychiatric Association. These core features can present differently from person to person, and ASD is considered a spectrum, meaning there is wide variation in how symptoms appear and evolve over time.

Some hallmarks of autism in adults include feeling awkward in social situations, difficulty understanding the feelings or thoughts of others, a preference to be alone, trouble making friends, and difficulty following or understanding social rules. Verbal and nonverbal cues can also differ, with some individuals struggling with eye contact, responding in a blunt manner, or taking statements literally. Importantly, many autistic adults do not display every characteristic, and behaviors and interests may change with age.

Repetitive or restrictive behaviors — such as following the same routine every day, noticing small details that others might overlook, and harboring very intense and specific interests — can also indicate autism, according to Autism Speaks. The organization notes that the presentation of these traits varies; some adults may show marked rigidity, while others exhibit subtler patterns.

Masking is a term used in the autism community to describe how an autistic individual hides symptoms to fit in and avoid drawing attention in social situations. Some people mask to avoid bullying, maintain friendships and succeed at work or school, Autism Speaks says. It is possible to mask without recognizing it, as some people adopt subtle stimming behaviors such as using fidget toys. Imitating speech or body language, forcing eye contact, or expressing facial expressions that feel unnatural are other forms of masking. While masking can help autistic adults navigate daily interactions, research has shown it can have negative effects on mental health, contributing to isolation and exhaustion, Autism Speaks notes.

Autistic girls and women have been found to be more socially adaptable than boys and men with the disorder, making them more likely to mask, according to research. The Centers for Disease Control and Prevention has reported that autism is about three times more common in boys than in girls. Experts like Alisha Simpson-Watt, a licensed clinical social worker and founder of Collaborative ABA Services, say masking often begins in childhood and can become ingrained, sometimes to the point that it feels like second nature. Cultural expectations can also influence masking, with social norms pressuring girls to be more accommodating or emotionally attuned, which can obscure signs of autism in women.

ASD is a spectrum, which means symptoms can vary widely from one person to the next. Simpson-Watt stresses that while core features remain the same, there are differences in social communication and repetitive behaviors, and how they present can differ across individuals. Recognizing the diversity of the spectrum is key to helping more adults receive the support and validation they need. For adults who believe they may have undiagnosed autism, the advice is to trust their instincts and pursue a formal evaluation. Start by speaking with a primary care physician or checking with an insurer for a list of qualified professionals who diagnose autism in adults. It is important to note that some insurance plans may have age related restrictions on coverage for autism evaluations, so initiating the process early can be beneficial.

Recognizing the diversity of presentations is also essential as people experience major life changes such as college transitions, career shifts, or changes in family status. These events can shift how autism presents itself, making ongoing evaluation and support important for adults who may not have had an earlier diagnosis. For those seeking clarity, a formal assessment often involves a comprehensive clinical interview, input from family or partners, and standardized testing to determine whether autism spectrum disorder is appropriate and to guide next steps for support and treatment.

Silence about adult autism can be harmful, educators and clinicians say, because untreated or unrecognized autism can affect mental health, employment, relationships and overall quality of life. As advocacy and education efforts expand, experts emphasize that understanding the spectrum’s diversity, including the likelihood of masking and gender differences, is crucial to improving access to diagnosis and services for adults who need them.

For adults who think they may have undiagnosed autism, the process can begin with a conversation about symptoms with a primary care clinician and then a referral to specialists who diagnose autism in adults. Insurance coverage and access to providers can vary, so early planning is advisable. As the autism community continues to push for better recognition, many stakeholders say the path to diagnosis for adults is becoming clearer, with a growing emphasis on validating diverse experiences and offering targeted supports to improve daily functioning and well being.

In the end, the goal is timely recognition and tailored support that respects each individual’s unique strengths and challenges. By acknowledging the breadth of autism in adulthood and promoting access to thorough evaluations, clinicians hope to reduce the long standing gaps in diagnosis and care for adults living with autism.