How to Diagnose Autism in Adults

Autism, clinically known as autism spectrum disorder (ASD), is a disorder that affects communication and social skills; may lead to increased sensitivity to sounds, smells, touch, and other things in the environment; some unusual behavior.

Most people with ASD are diagnosed as children, especially those with obvious symptoms. However, as autism is better understood, it is not uncommon for adults to wonder whether certain behaviors and traits in themselves (or a loved one) may be signs of ASD.

If you are one of them, this article will help you understand how to make a diagnosis of autism in adults. It covers characteristics and behaviors to look for, self-screening tools, and how mental health professionals typically evaluate adults, including ruling out other possible diagnoses.


Adults diagnosed with autism may be on the mild or high functioning end of the spectrum.

In the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), the manual used by mental health professionals to diagnose disorders, this is called “Severity 1”.

Many adults have mild autism symptoms, often related to social communication and sensory responses.

Often, however, until they become more aware of autism spectrum disorders are possibilities they consider themselves. Some people may not realize this until their son or daughter is diagnosed with autism, noticing similarities in the child’s characteristics, behaviors, or feelings to their own.

social communication symptoms

These relate to how you interact with other people. You may be aware that you have these symptoms since childhood, but you have learned to hide or manage them.

  • You are not sure what to wear in social situations or when to talk or keep quiet.
  • You used the wrong tone or wording when talking to someone. You may be speaking too loudly when you should be keeping your voice down.
  • You have difficulty understanding the body language or writing of others.
  • It’s hard to keep up with conversations, especially when you’re not interested in the topic.​​​ You have a hard time chatting.
  • You are so obsessed with a particular topic that it is almost impossible to change the subject.
  • You are not sure when it is appropriate to ask certain questions or express opinions; you may feel so uncertain that you do not say anything at all.
  • You have a hard time coping with change. You may stick to the same schedule, eat the same food, take the same route to work every day, and feel uneasy if your routine is interrupted.
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sensory and behavioral symptoms

Many of these are common in all people with ASD, but may be less pronounced in people with mild autism. They may look more like quirks than symptoms of autism.

  • You are very sensitive to light, sound, smell, touch and taste and do not like being touched or hugged.
  • You may need physical stress to feel calm. For example, if you are upset, you can hug yourself tightly.
  • You move in strange ways or make strange noises. This is a form of self-sedation called stimulation. Examples include pacing, rocking, spinning hair, and humming. If you’re in public, people may stare at you, but you can’t stop that behavior.
  • You have an “autism breakdown”. You will feel very frustrated and frustrated, unable to control what you say and do, and may even scare others.


While most people with autism are diagnosed in childhood, people with mild (grade 1) ASD may not be diagnosed until adulthood. This possibility will only come to their attention after learning more about the signs of ASD (eg, disliking being touched) and recognizing them in themselves or others (eg, children).


ASD’s self-screening tool is a questionnaire you can fill out yourself. Most are available online for free. They cannot confirm whether you have autism. However, they can help you decide whether you should have a professional for a formal evaluation.

The most common self-screening tools for ASD include:

  • Autism Spectrum Quotient (AQ-10): This is a 10-question screening tool adapted from a longer questionnaire called the Autism Spectrum Quotient (AQ). The AQ-10 is very popular, but be aware that some studies suggest it may not be the most reliable way to identify people with autism. You can take the AQ-10 test online.
  • Adult Repetitive Behavior Questionnaire 2 (RBQ-2A): This 20-item questionnaire focuses on Restricted and Repetitive Behaviors. It was found to be a highly effective screening tool for autism. You can use the RBQ-2A here.
  • Adult Social Behavior Questionnaire (ASBQ): The 44 questions in this tool focus on broad aspects of autism in adults. It is especially effective for mild ASD. It can be used to evaluate others as well as self-test.

Tests and Scales for Diagnosing Autism

Professional assessment

The only way to get an accurate diagnosis of autism in adults is to see a professional. They will observe your behavior, including how you speak and interact with them.

They will also have you complete one or more assessments that are more detailed than you can do yourself. In most cases, you will do this by answering the questions your doctor asks you out loud.

see who

Some health professionals may not immediately see autism as a possible diagnosis in adults. Women with ASD, in particular, are often overlooked.

This is why if you decide you need an evaluation, you should seek an evaluation from someone who has experience diagnosing ASD. Ideally, this person will have a background in working with adults, but this can be difficult to find.

In this case, Autism Speaks, a nonprofit ASD organization, recommends finding a developmental pediatrician, child psychiatrist, or pediatric neurologist who specializes in autism and considers evaluating adults.

You can also look for reputable local autism centers. One option: Belonging to the Center for Autism Autism Treatment Network.

diagnostic test

Tests you may be asked to take include:

  • Autism Diagnostic Observation Program, Second Edition (ADOS-2) Module 4: ADOS-2 is considered the gold standard for diagnosing autism in people of all ages. Module 4 is dedicated to adults and is not a questionnaire. Instead, the professional administering the test will observe how you respond to certain prompts. They evaluate what you say and what you do.
  • Developmental, Dimensional, and Diagnostic Interviews – Adult (3Di-Adult): This standard tool for diagnosing autism in adults focuses on how you communicate and interact in social situations. It also looks for restricted interests, such as obsessions with specific objects and certain behaviors.
  • Social Response Scale (SRS): This 65-question test is not typically used to diagnose autism, but to measure how impaired a person’s social skills are.
  • Autism Diagnostic Interview Revised (ADI-R): This test focuses on three main areas affected by autism: language and communication, social interaction, and repetitive behaviors or interests. The ADI-R has 93 questions.

Could it be Asperger’s Syndrome?

Asperger’s syndrome was once thought to be a separate autism-like disorder. However, in 2013 it was placed under the umbrella diagnosis of autism spectrum disorder (ASD) in the DSM-5. Today, the disorder once known as Asperger’s is often referred to as high-functioning autism.

Differential diagnosis

In adults, autism spectrum disorders can look a lot like other developmental or psychiatric disorders. These usually need to be ruled out in a process called differential diagnosis.

Autism is most often mistaken for Social Communication Disorder (SCD). People with SCD have difficulty using words and language correctly. For example, they may use overly formal words and tones in casual conversations with friends.

What’s more, studies have found that people with mental illness are not uncommon along with Autism Spectrum Disorder. For example, a 2019 meta-analysis found that among adults with ASD:

  • 33% have attention deficit hyperactivity disorder (ADHD)
  • 23% suffer from anxiety disorders
  • 12% suffer from depression
  • 10% suffer from obsessive compulsive disorder (OCD)
  • 10% have disruptive/impulse control/behavioral disorders
  • 5% suffer from schizophrenia
  • 5% have bipolar disorder

Providers may consider various additional evaluations based on other medical conditions they suspect.


Diagnosing autism in adults can be tricky. People who are not diagnosed as children may have mild symptoms that they unknowingly learn to mask or control.

That said, many traits and behaviors that a person may be aware of can be signs of autism, such as difficulty navigating social interactions and additional sensitivity to smell or touch.

People who suspect they may have autism can self-screen using free questionnaires found on the Internet. But to get a real diagnosis, it’s necessary to see a mental health professional.

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