What Are the Signs of Autism in Adults?

Many people do not recognize the signs of autism until adulthood. And, even then, it’s often mistaken for ADHD or another comorbidity. Here, learn the signs of ASD beyond childhood.

By Christine O'Rourke-Lang, Ph.D. Verified Updated on July 10, 2024

“If you know one autistic person, you know one autistic person,” says Stephen Shore, Ed.D., president emeritus of the Asperger’s Association of New England, and advisory board member of the Autism Society. Signs of autism present themselves in each person in a different way. In many cases, a person does not recognize these signs as autism until adulthood.

By clinical definition, autism is a lifelong neurological disorder. Chances are, adults who are newly diagnosed had mild or subtle symptoms throughout their lives that have now begun to affect them. Despite the worry that a diagnosis later in life can bring, know that there are many professionals and individualized services available to help you reach your goals.

Signs of Autism in Adults

Difficulty understanding the “non-written” rules of language, resistance to change, and reluctance to engage socially are signs of autism spectrum disorder. Some children and adolescents reach adulthood without facing these struggles. However, when adulthood hits, and the routine and structure of school life are gone, along with parent and teacher support, symptoms become more apparent and impactful.

Thirty to 60 percent of individuals with autism are also affected by ADHD. Symptoms of ADHD and autism often overlap — and the signs of each condition may look different in adulthood than they did in childhood. For example, according to the Centers for Disease Control, hyperactivity in adults with ADHD may present itself as extreme restlessness or high activity levels that wear out friends and family.

A distinguishing factor between the two conditions is social connectivity. Adults with ADHD often exhibit inattentiveness, social anxieties, and challenges with controlling impulses. Social deficits as a whole are a defining characteristic of an adult autism diagnosis. When a person with ADHD speaks out of turn, it is probably due to lack of impulse control. With autism, talking over someone is likely due to an unawareness of the expectations of speakers and listeners, and a lack of understanding of social contexts.

Signs of Autism vs. ADHD in Adults

Below are specific behaviors adapted from the diagnostic symptoms of autism and ADHD according to the DSM-5.

Signs of Adult Autism

Challenges taking turns in a conversation
Monopolizing conversation with one’s own interests or thoughts
Difficulty making interpersonal connections
Hyperfocus on a specific topic or interest
Abnormalities in eye contact and body language
Not “picking up” on body language and facial cues of others
Literal interpretation of language
Inability to “see” the perspective of others
Misperception of language or social situations
Challenges with adjusting behaviors to match different social contexts
Frustration and anxiety over unexpected changes in routines and schedules
Extreme rigidity
Socially awkward, not “fitting in” with any social circles
Difficulties with completing everyday life activities independently
Challenges with accepting feedback or corrections
Lack of motivation to engage with others

Take the Autism Symptom Test for Adults

Signs of ADHD in Adults

Often getting sidetracked with duties or projects
Trouble with planning
Making careless mistakes at work
Lack of attention to detail
Challenges with organization and maintaining schedules/appointments/deadlines
Frequently misplacing things (keys, wallet, glasses, cell phone)
Distracted easily by other things occurring in the environment
Forgetful
Fidgety/challenges with remaining seated for extended periods of time
Impatience
Excessive talking
Speaking out of turn/interrupting conversations
Blurting out responses to unfinished questions
Often restless

Take the ADHD Symptom Test for Adults

Diagnosis of Autism in Adults

If you suspect you have some of the symptoms of autism, schedule an appointment with your primary-care physician or a mental health practitioner familiar with ASD (More information on how to get evaluated for autism as an adult here). To date, there are no standardized tests used to diagnose adults with autism. Diagnosis involves four steps:

Make an appointment to review concerns with your primary care physician (PCP)
Your PCP can refer you to a qualified mental health practitioner
An evaluation may be recommended that would include self-reporting of symptoms, behavior checklists, and direct interactions and observations with a clinician. This information is usually combined with observations from significant others or close family members
A follow-up appointment to review results and discuss treatment options

Strategies for Autistic Adults

Interventions for adult autism include therapy and setting up environmental accommodations that increase independence and improve quality of life. Interventions also depend on the level of support an autistic individual may need, and which personal differences they want to keep or change.

Cognitive behavior therapy (CBT), for example, may help autistic individuals cope with and understand the ways they experience the world differently compared to neurotypical individuals.

As far as accommodations and supports in and out of the home, they can include but are not limited to:

assistive technology devices
psychoeducation
sensory-friendly spaces
coaching to support long-term goals

Applied Behavior Analysis (ABA), a widely used intervention for autism (especially in autistic children), is also an option. However, many autistic individuals reject ABA, viewing it as a method that trains individuals to behave “less autistic.”

For autistic adults who may opt for ABA, a typical approach focuses on outlining the individual’s goals and challenges that affect daily functioning, and implementing strategies to improve them in real-life situations.