Much of this article hinges upon challenging the misconception that autistic people aren’t able to apply a complex theory of mind—hence the etymology of the term “autism.”

High-masking autistic individuals often utilize a intensely analytical process known as "deep compensation" to achieve effective Theory of Mind (the capacity to understand other people by ascribing mental states to them, including the knowledge that others' beliefs, desires, intentions, emotions, and thoughts may be different from one's own) or “cognitive empathy” which differs from “affective empathy.” This can (often) allow autistic people to navigate even complex social situations “successfully,” albeit with greater effort and time. “Success” here varies based on history of intensely observing social behaviours, researching and practicing socializing, and trial and error, often having “better” outcomes in familiar scenarios.

Years or decades of practice masking can lead to very “effective,” though time-limited, masking of autistic traits (which is not healthy or desirable, generally). This is especially common among autistic people with average or above-average IQ and lower support needs. It can be very challenging to identify some autistic adults unless a thorough assessment is completed by an assessor with specialized experience.

Autism, as a neurodevelopmental disorder, is typically expected to be diagnosed during childhood. This common assumption contributes to the misconception that a diagnosis of autism in later stages of life is improbable. However, there are numerous reasons why autism might go unnoticed or undiagnosed in childhood, such as:

1. Misattribution and Co-occurring Conditions: An autism diagnosis may be overlooked when behaviours typical of autism are mistakenly attributed to anxiety, trauma, shyness, or other similar concerns (see diagnostic overshadowing). This misattribution is common due to the high rates of conditions that can co-occur with autism, complicating the recognition of underlying autistic traits. This issue is particularly pronounced if healthcare providers selectively focus only on certain aspects of a client’s experience, or if we “twist facts to suit theories, instead of theories to suit facts”—a classic example of confirmation bias.

2. Family Dynamics: When parents are neurodivergent or exhibit traits associated with the broad autism phenotype, autistic behaviours in their children may seem normal to them thus can go unnoticed. Considering the significant genetic links in autism, such scenarios are far more common than might be expected.

3. Abuse or Neglect: Traumatic experiences can mask or overshadow signs of autism, and when caregivers are disengaged from their parenting responsibilities, they are less likely to notice (or act on, if they do notice) autistic differences.

4. Stigma: A surprising number of parents who are told by a doctor, therapist, or teacher that their child is showing some autistic traits and that an assessment is advisable, but then the parents choose not to proceed any further. I empathize somewhat with these parents, as historically there has been a lot of stigma related to autism, but I believe this is an unwise choice and is detrimental to autistic people in almost all cases. It is extremely useful to know that you are autistic, if you are. Tragically, I hear variations of this story from many clients (probably 30 to 40%), often concluding with “growing up, my family didn’t believe in getting treatment for mental health concerns.”

5. Gender Bias in Diagnosis: Girls and women are often under-diagnosed with autism due to gender stereotypes and the misconception that autism predominantly affects males, leading to a bias in recognition and referral for diagnosis. This broadly applies to most marginalized groups, unfortunately.

6. Lack of services: Many regions, particularly more rural areas, have fewer mental health services or specialists available.

See this 2020 research for more details.

Social masking is very prevalent among autistic adults with average or above-average IQ, and this masking can make it hard to detect autistic traits. These clients often will have spent decades learning, with increasing subtlety, how to hide their autistic traits in response to all the implicit and explicit criticism and rejection they receive for social differences. Masking can lead to the under-recognition of autistic traits during social and clinical exchanges, particularly if the observer is not actively alert to this phenomenon.

Common Misconceptions and Factors that contribute to the challenges of identifying autism in adults:

1. Masking: described above. Adults who camouflage their autism traits in daily life likely engage in extensive masking and possess a functional to excellent theory of mind (attained via non-standard means). Without these abilities, their autistic traits would likely have been identified in childhood. This level of masking, which involves both shallow and deep compensation strategies, is exhausting and discouraged, as it can lead to burnout and other health issues. Again, masking can lead to the under-recognition of autistic traits during social and clinical exchanges, particularly if the observer is not actively alert to this phenomenon.

2. Gender Differences in Presentation: Autism tends to be diagnosed more often in males than females, which may have some genetic origins, and this certainly seems to be impacted by how people who are “assigned female at birth” tend to be socialized in the Western world. Autistic women quite often get mis-diagnosed or under-diagnosed with anxiety, borderline personality disorder, or bipolar disorder.

   Historically, many women’s health issues have been minimized, misdiagnosed, and dismissed in clinical and research contexts; see here, here, or here for background reading. Generally, the less social privilege you have, the more likely your experiences are to be marginalized in most of the world’s healthcare systems.

3. Evolution of Diagnostic Criteria: The diagnostic criteria for autism have undergone significant changes over time. Initially, the focus was mostly on autistic people with very high support needs, often overlooking presentations with average intelligence or lower support needs. Prior to DSM5 in 2013, you couldn’t have both an autism and ADHD diagnosis, even though these are now understood as having very high co-occurrence. Additionally, autism is (stereotypically) considered by some to be a “childhood condition,” and some healthcare providers may make the assumption that if you weren’t diagnosed as autistic in childhood then you almost certainly aren’t autistic.

4. Challenges in the Differential Diagnosis: Due to the significant overlap in traits between autism and other conditions, as well as the high incidence of co-occurring disorders, accurate diagnosis of high-masking autism can be challenging and requires extensive data collection and in-depth knowledge.

   Misdiagnoses or under-diagnoses frequently obscure the identification of autism in adults. Conditions such as anxiety, borderline personality disorder, PTSD, or ADHD are commonly diagnosed instead of autism, leading to a scenario where autism's primary characteristics are overlooked in favour of managing these other diagnoses which may or may not be accurate. These co-occurring diagnoses may exist alongside or even represent underlying autistic traits. Recognizing this complexity is important to understanding the full scope of the autistic experience in adults.

5. Societal and Cultural Factors: Societal and cultural norms can significantly influence the identification of autism. In some cultures, traits associated with autism may not be seen as problematic or may be attributed to other factors.

   Eye contact, for example, is used very differently in some parts of the world, as are other non-verbals. Many autistic people learn that eye contact is expected and force themselves to use it, and after decades of practice, sometimes only nuanced differences in eye contact modulation and integration with speech exist. Similarly, many autistic people use strategies to simulate or avoid the use of most eye contact in conversation (e.g., look at bridge of nose or eye brow instead, or take notes to indicate I’m paying attention but I have to look at my notes so I can’t look at you, inviting you to be next to me to see what I’m doing rather than across from me, etc.), with varying levels of success. Almost all high-masking autistic adults have at least a moderate understanding of the utility and expectations related to eye contact and can force themselves to use it temporarily, despite the discomfort (this is not encouraged).

   Regardless, there are a few countries were shaking your head for ‘yes’ and ‘no’ are (basically) reversed! As a clinician, it is all too easy to be unaware of some of these kinds of nuances and misinterpret something.

6. Lack of Awareness and Education: No one is an expert in everything, and expertise varies even within specialized fields. For example, as a psychologist my expertise does not extend to treating eating disorders or addictions, and I am not the right person to assess or treat those concerns. Further, I specialize in autistic adults; I do not assess or work with autistic children. Similarly, while doctors are highly specialized (in fields like psychiatry, surgery, or family medicine), public expectations often unrealistically assume that doctors have a broad knowledge base in all areas.

   This misconception extends to autism, particularly in adult presentations. Despite advancements, I frequently encounter healthcare professionals who are not adequately informed about the adult autistic experience, yet they are expected to offer diagnostic impressions, guidance, and support. The historical lack of autism awareness among educators and healthcare providers, coupled with limited parental understanding, has played a significant role in missed or delayed diagnoses. This knowledge gap was more pronounced for those who attended school in the 1980s, 90s, or early 2000s than it is today—and these the adults we’re talking about seeking a “late-diagnosis” now.

   This 2015 Study of Physician Knowledge and Experience with Autism in Adults highlights this issue. They interview 922 medical doctors and stated “Most providers reported lacking skills and tools to care for this adult patient population. A high proportion of adult providers were not aware that they had patients with ASD.”

   This 2019 systematic review covered Primary Care Physicians’ Knowledge of Autism and Evidence-Based Interventions for Autism. The authors concluded that primary care physicians “in a majority of studies had inadequate knowledge of autism and its associated treatments.” A search of the literature reveals a moderate amount of other related studies.

   My critique here is not intended to be directed at doctors. Similar challenges are evident across all healthcare sectors that I engage with and whose work I encounter (e.g., nurses, psychologists, clinical social workers, etc.). Of course, I also meet some healthcare workers who have incredibly deep knowledge and competence related to autism. The focus on physicians in my discussion stems from more accessible research or straightforward search terms, rather than a comprehensive reflection of physicians in particular. This possibly indicates a broader gap in research on this crucial topic across different healthcare disciplines.

7. Impact of Appearance/Social Presentation on Autism Recognition: Factors such as level of physical attractiveness can play a large role in perception of autistic masking and whether an autism diagnosis is believed or not. A colloquial term for this is “pretty privilege,” and extensive research over decades has shown that the more conventionally attractive a person is the more we pay attention to them, like them, want them to like us, want to help them out, empathize with them (especially with women), and so on. To some degree, the DSM5-TR addresses the effect of presentation and certainly functioning, stating that autistic “individuals with relatively better skills overall may experience different or even greater psychosocial challenges.”

8. Double Empathy Problem, Theory of Mind, and Alexithymia: Autistic individuals often perceive, think, and communicate differently from non-autistic individuals due to neurobiological variances, including differences in theory of mind and the frequent presence of alexithymia. These differences can become more pronounced in complex situations, and can lead to significant miscommunications. This is encapsulated in the “double empathy problem,” which posits that understanding often decreases as differences in perspective increase. This phenomenon is easily observed in cultural or socioeconomic disparities but is particularly relevant in autism, where differences in theory of mind are pronounced.

   Consider an autistic adult reflecting upon their unique experiences of emotions, sensory sensitivities, trauma, autonomic dysfunction, or burn out. Identifying whether one’s own subtle, internal experiences are atypical can be very challenging—especially given that approximately 50% of autistic people also have alexithymia. This challenge is compounded for those with difficulties in social communication (i.e., many autistic people), often making it hard to convey their nuanced experiences accurately to healthcare professionals.

   The risk of miscommunication is heightened when the listener is not autistic, leading to potential misdiagnoses. This risk is further heightened by masking, people-pleasing, difficulty regulating emotions, rejection sensitivity dysphoria, medical trauma, and so on. These issues can make interactions with healthcare professionals overwhelming (further reducing effective communication), particularly if the autistic individual's concerns are not taken seriously—a common and unfortunate reality.

   Miscommunication in such contexts can lead to misdiagnosis, with autistic individuals potentially receiving incorrect labels for their experiences. This misattribution risks inappropriate treatment, including unhelpful medication and support services, underscoring the need for healthcare professionals to develop a deeper understanding of autism's nuances. Training in recognizing autistic communication styles and adopting collaborative approaches to diagnosis and treatment can significantly improve care for autistic adults.

9. Misc: Some locations simply do not have adequate access to medical services, so the person might have otherwise been identified as autistic early on if they lived in a major city, but that’s not always the case. The internet allowed for vast sharing of information, and it’s never been easier to find great information about adult autistic experience, so people who wouldn’t have come across the information in past decades now are far more likely to do so and then wonder if they are autistic—though of course this brings along increased sharing of inaccurate information as well.

   
   The above is a long list, but hopefully it can help readers appreciate the complexity of the issue and dispel some oversimplifications or misconceptions.

In discussions about autism, it’s vital to approach with humility and openness, especially if one's familiarity with the DSM5-TR autism criteria might not be current. It may help to reflect:

• How many of the DSM5-TR criteria of autism can I, right now and without looking, list off?

• How much accurate detail can I provide on each criteria?

• Do I know which criteria go in which category?

• Do I know which criteria are mandatory for an autism diagnosis vs which aren’t?

• Did my list contain anything that’s simply not found in the criteria?

• Do I know what changed in the autism criteria when the DSM5 came out in 2013? Or what changed in autism definitions when the DSM5’s text revision released in 2022?
  

I mean this without judgement: holding strong opinions on the likelihood of someone being autistic without having a thorough understanding of the DSM criteria and how they appear in adults can inadvertently lead to overlooking subtleties in high-masking autism. There are many areas in the vast and complex field of mental health that are outside my expertise, and I try to be curious and open-minded when I encounter those rather than feel I need to have an immediate and definitive stance on everything.

It’s okay to “not know” everything. A current gap in specific knowledge does not detract from one’s competence as a medical or mental health professional. However, responses rooted in defensiveness or arrogance can be counterproductive. “The biggest threat to human intellect isn’t being ignorant, but being under the illusion of knowledge.” I recognize and value the continuous efforts made by healthcare professionals towards their ongoing learning and professional development. My appeal here is for openness to expanding our collective understanding of adults who exhibit high levels of masking in autism. For those interested in a deeper look, I have included a list of resources at the end of this article.

Recent data from the CDC illustrates a significant increase in the identification of autism, with rates escalating from 1 in 54 children in 2016 to 1 in 36 of all children by 2020. This rise suggests not only a potential increase in the prevalence of autism but also improvements in our ability to recognize and diagnose the condition more effectively.

Further, research shows that autistic people are over-represented in medical settings. A 2016 study found that people with autism were 2.3 times more likely to visit emergency departments compared to non-autistic people, and another 2016 study indicated that autistic adolescents and young adults accessed such services 4 times more frequently. Further, research suggests that 2.4 to 9.9% of adults in psychiatric inpatient settings are autistic. These statistics not only reflect the challenges faced by autistic individuals in navigating a world not designed for them but also highlight the critical need for healthcare professionals to deepen their understanding of autism. These statistics also show that healthcare professionals encounter autistic individuals within clinical settings frequently, and for many practitioners, perhaps much more often than previously understood.

The over-representation of autistic individuals in healthcare settings, paired with the growing prevalence of autism, emphasizes the necessity for healthcare professionals to refine their understanding of autism. This involves moving beyond old stereotypes and common misconceptions. To foster more effective and compassionate healthcare practices, therapists, nurses, and doctors are encouraged to embrace ongoing education about autism, including understanding its diverse presentations and best practices (e.g., sensory-friendly environments, appropriate communication strategies, specialized services, etc.).

Misconceptions about autism, particularly related to autistic people with high-masking presentations, persist widely even among healthcare professionals. We owe it to our autistic clients, patients, friends, and family to dispel these and update our knowledge. Keep in mind that autism manifests uniquely in each person, and the ideas shared here will not apply universally to all.

Heterogeneous Presentation? Autism is known as a “spectrum” but even so, there is surprising diversity in its presentation, and future research will surely evolve our current understanding. This diversity can complicate assessment, necessitating more time and specialization, and relates to the idea that “if you’ve met one autistic person, then you’ve met one autistic person.” Presentation, level of support needs, academic and professional achievement, hobbies, romantic connection, and social circles can differ markedly across autistic individuals.

Autism is a Male Disorder? Historically, autism diagnoses were more commonly made in males, leading to a persistent misconception. However, current understanding acknowledges that autism is significantly underdiagnosed in females and non-binary individuals, largely due to differences in presentation and biases within diagnostic criteria. This field is evolving and while definitive answers remain elusive, it's clear that autism spans all genders, necessitating a more inclusive approach to diagnosis and support.

Autistic people lack empathy? Empathy is multifaceted, encompassing cognitive (understanding others' thoughts and feelings) and affective (sharing emotional experiences) dimensions, see 1 or 2 and the related concept of theory of mind. Some autistic people experience differences in cognitive empathy (and emotional regulation, related to executive functioning differences), and many exhibit a heightened affective empathy and are often criticized for excessive sensitivity—to emotions, social situations, trauma, sensory experiences, and so on. This emotional landscape is further complicated by alexithymia, affecting around 50% of autistic people, which can impact self-care and emotional intimacy.

The social, sensory, and emotional nuances of autism can make some forms of everyday interactions daunting (the more nuanced the situation, the more challenging it can become (e.g., humour, romance, important career moments), leading to a preference for solitude despite a desire for connection. These challenges are exacerbated by societal tendencies to pathologize rather than support autistic differences, contributing to significant anxiety and the exhaustion of masking these differences to conform. In early 2024, I assessed a professional in her 40s who explained “I’ll always work alone when possible because I find other people distracting and often unhelpful. But working in total isolation (at my house for example), isn’t really my preference either. I like to see and be seen, I just don’t necessarily want to interact. I find total isolation is unrewarding but it’s definitely easier and emotionally less wearing,” (used with permission). The emotional wear she was referring to is from a lack of acceptance of autistic differences, and the exhaustion that results from trying to hide or mask those differences all day.

Autism is a childhood disorder? From a medical lens, autism is classified as a neurodevelopmental condition, and it persists throughout an individual's life. Autistic children become autistic adults. Instances where autism goes unnoticed or undiagnosed in childhood simply reflect missed diagnoses, not the absence of autism during early life. See section 1 of this article for a discussion on the numerous, yet unfortunately common reasons contributing to this kind of oversight.

High-masking = “normalcy”? Autistic masking involves both conscious and unconscious attempts to conceal one's authentic self, trying to adapt to societal expectations and coexist. While this practice may make individuals appear more "typical," it requires substantial effort and can lead to increased stress, anxiety, burnout, identity confusion, and potential delays in receiving diagnosis or support. High levels of masking are a coping strategy rather than an indicator of "normalcy,” but its nuance may lead to the under-recognition of autistic traits during social and clinical exchanges, particularly if one is not actively alert to this phenomenon. Notably, it can be challenging for people to stop masking during any particular moment, such as during a healthcare encounter, but this is more navigable when people feel safe and understood.

Everyone’s a little bit autistic? Distinguishing between temporary, episodic experiences and chronic, trait-like conditions is essential in healthcare. While it's true that many people may occasionally experience social awkwardness, feel intense interest in a hobby, or exhibit traits resembling anxiety or depression, these episodic moments do not equate to the lifelong, comprehensive experience of being autistic. Suggesting otherwise to autistic people is invalidating, potentially making them feel unsafe and misunderstood. Recently a client reported to me that their psychiatrist told them in a dismissive manner that “just because you don’t like loud noises doesn’t make you special.” In such contexts where rapport is already fragile or ruptured, attempting to normalize experiences with phrases like “we all feel a bit awkward sometimes” can come across as dismissive or even mocking, rather than empathetic and supportive. While I trust that most psychiatrists have good intentions and a genuine desire to help, the frequency with which my clients report such interactions—and the frequency with which similar experiences are echoed in many autistic communities—is deeply troubling.

Inflexibility and routines are just stubbornness? For many autistic individuals, routines and a predictable environment are key mechanisms for regulating anxiety as well as cognitive and sensory overload. This desire for sameness and predictability often intensifies when feeling distressed, overwhelmed, or burned out.

Sensory sensitivities are just picky preferences or dramatic over-reactions? These sensitivities are neurological and can significantly impact daily functioning and comfort. They tend to feel worse or more overstimulating during times of distress and burnout. Exposure therapy is generally ineffective for altering autistic sensory sensitivities and can be extremely distressing. What might seem like “improvement” often results from the individual masking their discomfort. A non-autistic person might imagine how it would feel for them to have an incredible headache or hangover but then have to attend a noisy children’s birthday party.

Autistic people either have an intellectual disability or are “savants”? Autism occurs across a wide range of intellectual functioning, including average to above-average intelligence, and autism presents somewhat differently in these people. Above-average intelligence often correlates with higher-masking presentations (which is not healthy or desirable). Autistic people often have “uneven cognitive profiles” which can also complicate the matter.

The nuances of autism in high-masking adults are easy to overlook or misunderstand. I encourage those who are interested in or work closely with autistic adults to revisit the DSM-5-TR criteria in brief here, and ideally review the full details in the DSM (~14 pages). This resource is invaluable for clarifying the precise requirements for a diagnosis and dispelling some common misconceptions.

The criteria outlined in the DSM-5-TR offer a fairly comprehensive, if abstract, framework for understanding autism. In adults, the A series criteria (social/emotional) tend to be the more subtle areas that deserve the most time and attention in an assessment. The social/emotional autistic traits are typically where most energy is being spent masking, and they are less straightforward than the B series criteria. Note that autistic people who aren’t diagnosed in childhood often exhibit effective or even exceptional social masking abilities.

The B series criteria, while important, are much more straightforward and easier to investigate. Note that only any 2 of the 4 B series criteria are required for a diagnosis, so a person can use no stimming behaviours and still be autistic, or have no “special interests”, or no sensory sensitivities (or mostly have hypo-sensitivities, which can be much harder to notice), and so on. Clarifying the exact nature and origins of a person’s traits related to autism’s B series criteria is often very important in a differential diagnosis—especially with personality disorders.

A careful and thorough differential diagnosis (criteria E) is a key aspect of assessing adults who may be autistic, as is gathering as much collateral information as is reasonably possible from their current life and developmental years (criteria C). It’s understood that the older a person becomes, the more challenging it can be to gather information about their youth, and if needed, a diagnosis can be made without it. If autistic traits weren’t impacting the person’s functioning and quality of life (criteria D), then they probably wouldn’t be speaking with you about it, but of course this is an important criteria to investigate as well.

Accurate autism assessment in adults requires a detailed understanding of the DSM5-TR criteria in addition to extensive content knowledge, with special attention given to the subtleties of the A series criteria often obscured by high-masking behaviours. This increases the likelihood of accurate diagnoses, addressing common misconceptions and enabling appropriate support for those who often mask their autistic traits (which can be very challenging to stop doing, even when we intend to).

Awareness of the high prevalence of co-occurring conditions in autistic individuals is crucial for healthcare providers to offer effective clinical support. A 2019 meta-analysis highlighted significant rates of additional diagnoses among autistic people, as an example of the potential complexity of their healthcare needs:

• 28% had ADHD

• 20% had an anxiety disorder

• 13% had sleep-wake disorders

• 12% disruptive, impulse-control, and conduct disorders

• 12% had depressive disorders

• 9% had OCD

• 5% had bipolar disorder

• 4% had schizophrenia spectrum disorders

Further, approximately 50% of autistic people have alexithymia, which profoundly affects emotional awareness/health, relationships, and (chronic) stress management capabilities. The prevalence of epilepsy, tic disorders, autonomic dysfunction, trauma and stress-related issues (including gastrointestinal problems, sexual dysfunction, cognitive and memory complaints), and various chronic illnesses like hyperlipidemia are also notably higher in this population.

Autonomic dysfunction is more common in autistic people. It may present subtly and with an insidious onset, making it challenging to articulate their experience effectively—particularly for clients with alexithymia. Sleep quality problems occur at significantly higher rate in autistic people versus non-clinical groups. This 2022 meta-analysis stated that “sleep problems were significantly associated with more clinical symptomatology and worse daytime functioning. Subgroup analyses demonstrated that sleep problems were most strongly associated with internalizing and externalizing symptoms and executive functioning, followed by core autism symptoms, family factors, and adaptive functioning.”

Stimulant medication is often considered for autistic individuals due to the high co-occurrence of ADHD. However, more research is needed, as autistic people commonly report substantial side effects from stimulants, including worsened sensory sensitivities and difficulties with tasks that involve both emotions and executive functioning, such as tolerating ambiguity or task switching. Standard psychotherapy treatments for mental health concerns like anxiety or trauma don’t always align well with the autistic experience, leading to frustration. However, when therapies are adapted to the autistic client's understanding, they can be highly beneficial. Even better would be to include resources and approaches created by autistic people. Of course, these approaches will be unavailable if a healthcare worker is unaware (or unaccepting) that their client is autistic.

Autistic people tend to think and communicate differently than most non-autistic people, favouring concrete, precise, and direct communication. Connecting autistic individuals with neurodivergent communities and resources, alongside informed and empathetic non-autistic clinical support, can enhance care. Like any cultural or identity factor, practitioners have to keep in mind that every autistic person has a unique experience of being autistic. The quality of the therapeutic relationship has been repeatedly shown to be one of the most important factors impacting outcomes in a wide variety of healthcare settings (e.g., in surgery, psychotherapy, physiotherapy, etc.). It is just as important to create good, safe relationships with autistic clients as it is with any other client—possibly more so given the lifetime of criticism, dismissal, and self-doubt most late-diagnosed autistic people have experienced.

This kind of information is critical for medical professionals when trying to understand and treat autistic clients. Without recognizing an individual's autism—or worse, dismissing an existing diagnosis—there is a heightened risk of misdiagnosis, inappropriate, or delayed treatment for co-occurring conditions.