Autism Spectrum Disorder

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 symptoms of ASD and how Applied Behavior Analysis (ABA) can help both children and adults with autism.

Concept of autism and autistic development disorder as a symbol of a communication and social behavior psychology as a chalk drawing on asphalt in a 3D illustration style.
Concept of autism and autistic development disorder as a symbol of a communication and social behavior psychology as a chalk drawing on asphalt in a 3D illustration style.

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“If you know one person with autism, you know one person with autism,” 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:

  1. Make an appointment to review concerns with your primary care physician (PCP)
  2. Your PCP can refer you to a qualified mental health practitioner
  3. 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
  4. A follow-up appointment to review results and discuss treatment options

Strategies for Adults with Autism

The most effective therapy for autism is Applied Behavior Analysis (ABA). Often thought of as an intervention for children or more impaired individuals with autism, ABA is now used to treat ASD across the lifespan. The goals of ABA involve teaching socially significant repertoires leading to increasing appropriate behaviors, decreasing negative behaviors, and fostering good social relationships. Learning new skills through behavior therapy can overcome symptoms of ASD that are interfering with everyday life.

Here is the typical six-step approach used in ABA:

Step 1. Make a list of desired goals

Begin by identifying a person’s challenges and working to meet each one of them. Goals should be concrete and specify the behavior to be targeted. For example: “Wait until another person is finished speaking before beginning to talk” is a concrete goal. “Get better at conversation skills” is too vague. Developing a meaningful goal involves practicing a behavior as a person faces it in real-life situations.

Step 2. Prioritize goals

Challenges that occur most frequently and that have the greatest impact on daily functioning should be addressed first. When you make progress with one goal, move on to the next.

Step 3. Design strategies to address goals for skill development

Therapy may be broken down into small, incremental components to reach long-term goals. These smaller strategies must be thoughtfully planned, sequenced, and delivered in a systematic way. Examples of strategies include positive reinforcement, the use of visual cues and text prompts, direct or explicit instruction, social stories and scripts, role playing, video modeling, behavior checklists, self-monitoring, and task analyses.

Step 4. Practice applying skills in a functional way

In addition to sitting across from a therapist and working on strategies, practicing those skills “in real life” is a big part of the therapy process. Repeating a behavior, combined with opportunities for actively applying the skill in real life, along with immediate feedback, helps adults acquire and maintain a skill. Practicing to meet a goal in real life might involve working on a social script for ordering from a menu at a restaurant. The next step would be going to a restaurant when hungry for dinner and ordering a real meal from the real menu.

Step 5. Always have a Plan B

Most autistic adults like order and predictability. But they need to know how to handle unexpected changes. Behavioral interventions should focus on preparing appropriate responses when things do not go as planned. The most effective way to address disappointment and inflexibility is to systematically incorporate those scenarios into the therapy process. For example, in the restaurant situation above, the social script should involve practicing a greeting, previewing the menu to order independently “on the spot,” but it should also include a response to the waiter who may say, “Sorry, we are out of that tonight.”

Step 6. Monitor, evaluate, and celebrate progress

Any effective therapy should incorporate data collection and analysis to assess progress. The information gathered should tell you when to move on to a new objective as a goal is met, or when an additional strategy has to be employed to facilitate skill development. Positivity in the therapy process means highlighting each accomplishment and building on successes.

Signs of Autism in Adults: Next Steps


Christine Lang, Ph.D., is associate professor and chairman of the special education department at Mercy College, in New York City and Westchester, New York.

Updated on July 29, 2021

3 Comments & Reviews

  1. “Challenges,” “inability,” “lack,” “awkward,” do non-autistic people hear themselves when they describe people with autism? This is what you get when you speak on behalf of others rather than letting them speak for themselves. Instead of framing the mannerisms of autistic people as inherently flawed, let autistic people tell you the ways in which non-autistic people make their lives difficult.

    I encourage anyone reading this to check out the Autistic Self Advocacy Network (ASAN) at autisticadvocacy dot org for information for autistic people and their loved ones written by autistic people, which focuses on the joys, rather than the shortcomings, of being on the spectrum, and ways to best support the autistic people in your life.

  2. I really like this magazine but I think you need not only more Autistic contributors but also Autistic editors and staff. The reason being is you exclusively use person-first language (disliked by MOST autistic individuals) and praise ABA therapy, which is getting largely denounced nowadays for its ineffective and abusive methodology. Shame on you, ADDitude mag.

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