Signs of autism in adults

Autistic adults

Autism can impact children, but autism doesn't go away when you grow up, so adults who are autistic stay that way for life. On the other hand, because adults are more mature and experienced, many of them learn to live with their autism, and sometimes it's harder to tell that they're autistic. For example, like most adults, they are better at restraining themselves in public, they manage their emotions better and they have the tools to function despite their challenges. Many have memorized how to pretend to act like others, or how to hide their peculiarities. Often, they have great difficulties, but they try to keep them to themselves. Also, many autistic adults grew up at a time when research on the subject was less advanced, making diagnosis more difficult.

Why could an adult be autistic without having been diagnosed as a child?

Late diagnosis of autism in adults is a problem. Autism can vary considerably in terms of symptoms and severity. While some individuals may have intellectual disabilities or verbal communication difficulties, others may have cognitive abilities that are average or above. This makes diagnosis particularly difficult, especially in adults who were not diagnosed in childhood.

Difficult access to diagnosis

Four out of five adults report difficulties accessing an assessment and obtaining an official diagnosis. Many adults are also victims of misdiagnosis.

80% would have difficulty accessing the diagnostic process.

Source : Hop’ toys

Autism without intellectual disability

A large part of the problem concerns those who have no associated intellectual disability. These people have verbal communication skills and a cognitive level that is average or better. As a result, a large proportion of these people are not diagnosed until adulthood, and some never are. Yet the absence of intellectual disability does not prevent them from experiencing social difficulties.

Autistic woman

It seems that women are diagnosed later than men. This could be due to real differences in the manifestations of autism, or to sociological factors relating to gender. They would find it easier to imitate others and hide their particularities. Their need for solitude is more easily tolerated, and their interests are often more socially accepted. Many women have also been wrongly diagnosed with depression, bipolar disorder or borderline personality disorder, for example.

Evolving knowledge of autism

Many autistic people grew up at a time when there was less research on the subject. This lack of knowledge may have made their diagnosis more difficult or led to misdiagnosis.

Symptoms and signs of autism in adults

Social maladjustment

Adults showing mild autistic traits may often seem socially awkward. This awkwardness can manifest itself in a variety of ways, including not understanding the nature of conversations or talking too much about themselves, without leaving room for others to express themselves. In addition, they may ignore certain social cues, such as facial expressions and body language.

Specific or special interests

Wrongly referred to as restricted interests, specific or special interests are central to the functioning of autistic people, and can sometimes be confused with the ordinary passions we can all have. However, what distinguishes an ordinary interest or passion from the specific interests of autistic people is their nature and intensity.

They are so characteristic of autism that they form part of the diagnostic criteria defined by ICD-10 and DSM-5.

They are included in the category of repetitive and restricted behaviours (although the word restricted should be avoided).

These interests can manifest themselves as a preoccupation with one or more subjects that may be deemed unusual or excessively circumscribed in terms of definition. For example, it could be a strong attachment to uncommon objects, such as wanting to know and collect every type of light bulb in existence, or knowing all the train timetables in a region.

They can also manifest themselves in the amount of time devoted to an interest that might seem ordinary. For example, an autistic child might have a passion for cats, which is common. However, the amount of time he or she devotes to this interest would be considered out of the ordinary, especially in an adult.

Men and boys are more likely to have interests considered “abnormal” by others.

Repetitive behaviours

Lower-order repetitive behaviors

 These include movements such as clapping hands, manipulating objects, rocking the body, and vocalizations such as grunting or repeating phrases (echolalia).

Higher-order” repetitive behaviours

They include autistic traits such as routines and rituals, the importance of similarities, and special interests.


Autistic people can be inflexible to routines or rituals. For example, they may feel extreme distress at small changes.

Sensory hypersensitivities and hyposensitivities

It’s not a diagnostic criterion, but sensory hypersensitivities and/or hyposensitivities are very common in autistic people.

Sensory hypersensitivity

Sensory hypersensitivity is an above-average perception of certain senses. It’s not a matter of having superhero senses, it’s that the brain prioritizes this information, which can become overwhelming.

Sensory hypersensitivity

Sensory hypersensitivity is a lower-than-average perception of certain senses. It’s not a matter of having paralysis of the senses, it’s that the brain retains or masks this information, which can become problematic.

Distinct reactions to several stimuli

Eye contact

Some autistic people make no eye contact at all. Others focus on a part of the face other than the eyes, and some have learned to look into the eyes, but may do so awkwardly, and this may seem insistent or inappropriate. The point is that eye contact, even when learned, can remain atypical, different from the norm.

Co-occurring conditions

Most of the time, autism is accompanied by other peculiarities, challenges, differences and/or disabilities. Examples include intellectual disability, dyslexia, Tourette’s syndrome, epilepsy, ADHD, eating disorders, anxiety, sleep disorders and depression.

Signs visible from childhood

Many of the signs and symptoms of autism are visible in early childhood. To consult them, see

The complete list of possible differences

Autism varies so much from person to person, and is so difficult to identify in adults, especially those who have learned to mask, that it’s important to think about all aspects of life and daily living, to draw up a list of everything that’s different about the person. This list is essential for a clear diagnosis. This page is designed as an aide-memoire for analyzing every aspect of a person’s functioning in order to bring out the differences.