There are several tests to diagnose autism in adults, but there is no single, accepted clinical approach to diagnosing the disorder in adults. Instead, many adults must go to their doctor or therapist after reading others’ personal accounts of autism and learning more about the symptoms of autism.

People who do not get the right diagnosis until later in life may have milder symptoms than those who are diagnosed as children. They will still struggle with communication, socializing, cognition, and motor skills. As a result, they will still benefit from behavior therapy.

Better Diagnosis Criteria

Autism spectrum disorder (ASD), commonly called autism, is a developmental disorder that does not have a specific genetic component that can be screened for in infants.

The condition is typically diagnosed on the basis of behavioral differences between people with autism and neurotypical individuals. This means that behavioral differences need to be noticeable. Since autism is a spectrum disorder, there are many symptoms that can range from mild to severe. Some symptoms may never occur, which can make getting an accurate diagnosis tough.

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) took several conditions like Asperger’s syndrome and listed them as part of ASD. This adjustment has helped clinicians refine their ability to diagnose autism in children and adults.

According to the Centers for Disease Control and Prevention (CDC), 1 in 54 children in the United States has a diagnosis of autism today. The rate has increased substantially, but this is not because there are more children being born with autism. It is because the diagnostic criteria for the condition has clarified how the condition will appear to pediatricians, so they have better awareness of the condition. This allows them to draw more accurate conclusions and get children the help they need sooner.

Autism in Adults: Being Diagnosed Late in Life Is Challenging

With the adjustments in both the DSM-5 and its predecessor, the DSM-IV, to the definition of autism, more people are also being diagnosed with this developmental condition later in life.

Typically, people who are on the autism spectrum but do not receive a diagnosis until adulthood have milder symptoms. They may feel like they do not belong; they may wonder why they struggle to maintain friendships or relationships; or they may first receive a diagnosis of a co-occurring condition like depression or anxiety, which developed because of social isolation or communication struggles with others.

Updated diagnostic criteria for autism also mean that adults who may have received different diagnoses in childhood might be re-diagnosed later in life. Some people may have worked to hide their symptoms from others, struggling to fit in, so their communication or socialization struggles went unnoticed.

Testing children for signs of autism is a much more established practice, so many adults who are on the autism spectrum end up self-diagnosing themselves. Then, they seek help from a doctor or therapist who can provide an actual diagnosis. A medical diagnosis is a vital step to getting the right type of behavior therapy to understand and manage symptoms.

How Adults Discover They May Be on the Autism Spectrum

A recent CDC study reported that 2.2% of American adults are on the autism spectrum. This information was based on projections of how many children had been diagnosed with autism or a related condition that the DSM-5 now considers autism.

There may be more adults with autism who are diagnosed much later in life. However, there are few screening tools that are designed specifically for adults, so many medical professionals rely on talking about childhood experiences or on information their client gathered while self-diagnosing, which the medical professional can expand on.

If you are an adult with autism, you might have:

  • Been diagnosed with a mental or behavioral health disorder, or an intellectual disability, as a child but now understand those symptoms as closer to autism.
  • Felt socially isolated, different, or alone without understanding how to solve the problem.
  • Read about autism and recognized symptoms in yourself or feel acutely that your experience is being described.
  • A child in your family who has been diagnosed with autism, and you recognize the symptoms in yourself based on their diagnosis.

Since more people are discussing their personal experiences with clinical diagnoses, especially later-in-life diagnoses, through social media, more adults have begun to self-diagnose based on these personal stories. If you are one of these adults, finding a therapist or general practitioner can help you get screened for autism using one, or a few, screening questionnaires and a one-on-one discussion.

While you may suspect you have autism, you can’t officially diagnose yourself. You need a doctor to assess you and make an official diagnosis.

Current Diagnostic Tests for Autism in Adults

There are several tests that can help clinicians diagnose autism in adults.

  • ADOS 2 Module 4: The Autism Diagnostic Observation Schedule, 2nd Edition, Module 4 is specifically used to diagnose autism in verbally fluent adults. There are several questions regarding common symptoms of autism, including those related to language and communication, reciprocal social interactions, and restricted or repetitive behaviors. The clinician will score each of these areas 1 to 3, and then provide a diagnosis based on the total score.
  • ADI-R: This is a survey typically used to diagnose children, based on interviewing their parents. However, some clinicians may use it to diagnose adults with autism, using the same interview questions but instead asking about their childhood experiences.
  • 3Di Adult: The Developmental, Dimensional, and Diagnostic Interview – Adult Version was developed specifically to help clinicians understand signs of autism in their adult clients. It has shown higher sensitivity and accuracy than other tests.
  • AFQ: The Actions and Feelings Questionnaire focuses on differences in motor cognition. This involves how humans process and understand their physical movements, which can help adults relate to the world. This includes social processing, which can help identify adults who are on the autism spectrum.
  • RAADS-14: The Ritvo Autism and Asperger Diagnostic Scale-Revised is an 80-question survey to detect autism. The RAADS-14 is the streamlined 14-question version.
  • AdAS Spectrum: The Adult Autism Subthreshold Spectrum is another highly sensitive and accurate questionnaire developed to screen for autism symptoms in adults.

While these are a few of the many potential screening tools to help adults who are on the autism spectrum, there is no single set of approved tools for adults. If you are an adult and you think you are on the autism spectrum, it’s a good idea to get a second opinion or ask about potentially taking multiple tests, so you can best understand all your symptoms.

It may be important for you to conduct your own research so you can discuss your experiences with your doctor or therapist. Assessing your own potential symptoms of autism will not get you access to appropriate treatment, as a formal diagnosis from a doctor or counselor will, but it can give you a better understanding of your own experience. This can encourage you to pursue further treatment if needed.

Work With a Professional

Several websites offer “self-diagnosis” tests or quizzes for autism, but these are not definitive or even approved by medical practitioners who understand autism spectrum disorder. Reading information about autism, and the experiences of people who were diagnosed as adults, can be more helpful. This information can guide you into a discussion with your doctor, so you can get therapeutic support.

Adult Symptoms of Autism

Potential symptoms of autism in adults, which can help you screen whether you might be autistic or not, include:

  • Trouble understanding what others are thinking or feeling.
  • Being confused by idioms or expressions, such as “don’t count your chickens before they hatch.”
  • Inventing your own words or expressions to describe things.
  • Wanting to have a few close friends or one best friend, but never maintaining those relationships and being unable to understand why they do not last.
  • Trouble regulating your emotions.
  • Difficulty managing the natural give and take of a conversation. Instead, you talk more about your favorite subject or take focus in the conversation if the topic is something you understand.
  • Participating in solo activities in your leisure time or participating in a limited range of activities.
  • Strict consistency to daily or weekly routines and extreme difficulty when there are changes.
  • Discomfort looking others in the eye, preferring instead to look at a wall, your shoes, or somewhere else so you can listen better.
  • Being clumsy, bumping into things, dropping things, or tripping over your own feet frequently.

If these and other symptoms of autism feel very familiar, find a therapist who specializes in autism, or ask your doctor for a referral to a specialist. These professionals can help you get the right treatment based on your symptom severity.

Some disorders are common in people with autism, so you may need assistance with other conditions. For example, co-occurring anxiety and depression are very common in adults who are diagnosed with autism later in life. Therapists and doctors can help you mitigate the symptoms of these co-occurring disorders as well.


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First U.S. Study of Autism in Adults Estimates 2.2 Percent Have Autism Spectrum Disorder. (May 2020). CNN.

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