Autism’s Confusing Cousins
A differential diagnosis for the weird and the awkward
“I think that these days what we mean by “autism” is basically “weird person disease.””
Sorbie Richner, Rich Girl Rehab
“Accurate diagnosis requires consideration of multiple diagnoses. Sometimes, different diagnoses can overlap with one another and can only be differentiated in subtle and nuanced ways, but particular diagnoses vary considerably in levels of public awareness. As such, an individual may meet the diagnostic criteria for one diagnosis but self-diagnoses with a different diagnosis because it is better known.”
Sam Fellowes, Self-Diagnosis in Psychiatry and the Distribution of Social Resources
Unsurprisingly, these days I meet many people in the psychiatric clinic who are convinced that they have autism, or suspect (with various degrees of confidence) that they have autism, or report being diagnosed with autism at some point in their lives by some clinician. And for a fair number of such individuals, I cannot say with reasonable certitude that they have autism. The reasons they give for considering autism vary widely, but tend to be along the lines of…
“Eye contact makes me very uncomfortable.”
“I suck at small talk.”
“I have rigid routines.”
“I hyper-focus on my hobbies.”
“I am always fidgeting.”
“Social interaction exhausts me.”
“I really bad at making friends.”
“I don’t fit in; people find me weird.”
What’s interesting about many of the items above is that the number one diagnostic possibility in my mind is an anxiety disorder of some sort. I remember seeing a woman who was a classic example of someone with high neuroticism, poor self-esteem, and severe social anxiety, and she had believed for much of her life that she was autistic because some random doctor somewhere at some point (she couldn’t even remember who or what sort of assessment this involved) had told her that she had autism, and she believed it because it fit in with her experience of being awkward-shy-weird.
It is common for me to meet individuals who think they have autism and find myself thinking, “schizoid,” “obsessive compulsive,” “cluster B,” “social anxiety,” “generalized anxiety,” “trauma,” “socially awkward,”… None of these, however, have the mimetic virality of autism.
I don’t want to come across as being skeptical of the reality of autism as a diagnosis or as asserting that most people are misdiagnosed. Autism exists, to the extent that any psychiatric disorder exists. Not everyone is misdiagnosed, perhaps even most people. I am not trying to say, “autism is bullshit.” It’s not. I offer the diagnosis of autism as a clinician perhaps as often as I find myself doubting it.
What intrigues me is that people are drawn to autism as a diagnosis because it seems to offer recognition of something they’ve lived with: they may be deeply awkward, terribly shy, or bad with people, they may struggle with social interactions, they may find other people annoying, other people may find them weird, they may have a hard time connecting to others, they may have been bullied, and they may have directed their loneliness or introversion towards peculiar interests or hobbies. Autism seems to them to capture all that. It seems like an apt and appealing narrative. But autism may also be the only relevant diagnosis they’ve heard of or are familiar with. They haven’t seen any cool TikToks about being schizoid. No one’s offering them quizzes about being schizotypal. A random pediatrician or primary care doc is not going to tell them they have an obsessive-compulsive style of personality. So when some professional doubts that they have “autism,” they see it as a dismissal or rejection of their “lived experience.” Of course, I am weird-anxious-awkward. How can you say otherwise? What they don’t know is that the choice is not between autism or nothing, but rather between autism and about a dozen other diagnostic possibilities.
So for the sake of our collective sanity, let’s consider a few of them…
To be diagnosed with autism spectrum disorder according to DSM-5, a person must have ongoing difficulties in social communication and interaction in all three areas: trouble with back-and-forth social connection, problems with nonverbal communication like eye contact and body language, and difficulty making or keeping friendships. They also must show at least two types of repetitive or restricted behaviors, such as repetitive movements or phrases, needing things to stay the same, having very intense focused interests, or being unusually sensitive (or under-sensitive) to things like sounds, textures, or lights. These patterns must have been present since early childhood (even if they weren’t noticed until later when life got more complicated), lead to substantial impairment in functioning, and can’t simply be explained by intellectual disability (or other psychiatric disorders).
To “have” autism is simply to demonstrate this cluster of characteristics at the requisite level of severity and pervasiveness. It doesn’t mean that the person has a specific type of brain attribute or a specific set of genes that differentiates them from non-autistics. No such internal essence exists for the notion as currently conceptualized.
Autism spectrum is wide enough to have very different prototypes within it. On one end we have profound autism, representing someone with severe autistic traits who is completely dependent on others for care and has substantial intellectual disability or very limited language ability. At the other end, we have successful nerdy individuals with autistic traits and superior intelligence, often seen in science or academia, à la Sheldon Cooper. (Holden Thorp, editor-in-chief of the Science journals and former UNC chancellor, for example, has publicly disclosed his own autism diagnosis.) This wide range is confusing enough on its own, even without considering other conditions that can present with autism-like features.
Autism cannot be identified via medical “tests.” It is identified via clinical information in the form of history, observation, and interaction, and the less information available or the more unreliable the information provided is, the more uncertain we’ll be. To have autism is basically a judgment call that one is a good match to a descriptive prototype. We can get this judgment wrong, and we sometimes do get it wrong. (There is nothing wrong with this fallibility as such, as long as we recognize it. Lives have been built on foundations less sturdy.)
Autism as a category or identity has taken on a life of its own. I am aware that not everyone in the neurodiversity crowd accepts the legitimacy of clinician judgments or clinical criteria as outlined in the diagnostic manuals, such as the DSM and ICD. There are other ways to ground the legitimacy of self-diagnoses, in theoretically virtuous accounts or pragmatic uses, which require distinct considerations of their own; I don’t reject that. But here, I am concerned with autism as a clinical diagnosis and the accuracy of autism understood in terms of alignment with clinical diagnosis. Would competent and knowledgeable clinicians with access to all relevant clinical information concur that the person’s presentation meets diagnostic criteria for autism? If you don’t really care about that, this post is not for you.
In discussing the differential diagnosis below, I am relying on currently accepted clinical conceptualizations for convenience of public communication. These clinical constructs are subject to their own debates. Personality disorders, for instance, are increasingly being conceptualized dimensionally, and their very characterization as disorders of personality is under dispute. The diagnostic boundaries between conditions are scientifically unclear and often reflect clinical convention.
Schizoid Personality
Schizoid personality describes people who have little desire for close relationships and prefer solitary activities. Unlike people who are simply shy or socially anxious, individuals with schizoid personality style genuinely don’t find relationships rewarding or necessary. They typically appear emotionally detached or cold, show restricted emotional expression, seem indifferent to praise or criticism, and have few if any close friends or confidants. They often live quietly on the margins of society, pursuing solitary interests or jobs. They keep their inner worlds (which can be quite rich) private and don’t seek emotional intimacy with others.
In autism, social difficulties stem from genuine challenges with processing social information: difficulty reading facial expressions, understanding implied meanings, picking up on social cues, knowing unwritten social rules, etc. Individuals with schizoid personality are thought to typically understand social conventions but they may nonetheless have difficulty making sense of other people’s behavior.1 They withdraw from genuine disinterest as well as some degree of impairment in social cognition. Schizoid personality also lacks the additional features of autism (repetitive or restricted behaviors, various sensory sensitivities).
Schizotypal Personality
Schizotypal personality describes people who have odd or eccentric beliefs and unusual perceptual experiences, and these can lead to difficulties in close relationships. Whereas schizoid personality involves disinterest in relationships, schizotypal describes strange ways of thinking and perceiving the world. People with schizotypal personality might, for instance, believe in telepathy, feel they have special powers, or think random events have special meaning for them, or have unusual perceptions (like feeling a presence in the room or hearing whispers). They typically have few close friends. They can experience social anxiety that doesn’t improve with familiarity, and they may appear paranoid or suspicious of others’ motives. Both schizotypal personality and autism can involve social difficulties and odd or eccentric behavior, but in schizotypal personality, the peculiarity fits within a broader pattern of magical thinking and eccentric tendencies.
Obsessive-Compulsive Personality
Obsessive-compulsive personality describes people who are preoccupied with perfectionism and control. They tend to be rigid rule-followers who want things to be done “the right way.” They have difficulty delegating tasks, and get caught up in details to the point of losing sight of the main goal. They can be workaholics. They can ignore fun and friendship, are rigid when it comes to moral or ethical issues, and are controlling and stubborn. Obsessive-compulsive personality and autism both involve rigid adherence to routines, rules, and particular ways of doing things. In obsessive-compulsive personality the rigidity is based on anxiety about loss of control. They’re consciously or unconsciously trying to manage anxiety through control and perfectionism. In autism, the need for sameness and routine has different functions. It provides predictability in a world that can feel confusing or helps with sensory regulation instead of anxiety-driven perfectionism.
Social Phobia
Severe social anxiety is a strong, persistent fear of social situations in which a person might be judged, embarrassed, or humiliated. Social anxiety disorder can be crippling and overwhelming for many. People with this condition are overly worried about saying something stupid, looking foolish, being humiliated, or being rejected. They tend to avoid social situations altogether, which can lead to social isolation as well as employment difficulties and relationship problems. Both social anxiety and autism involve social difficulties and social withdrawal. Social anxiety tends to get much better in comfortable, safe environments (like with close family or friends) whereas autistic social differences tend to be more consistent across contexts.
Borderline Personality
People with borderline personality disorder experience extreme mood swings and chaotic relationships, alternating between idealizing and devaluing others . They have intense emotional instability, an unstable sense of self, and a fear of abandonment . It may look like autism in terms of social issues, emotional dysregulation, rigid thinking and feeling different than the crowd. The main differences are that borderline centers on intense preoccupation with relationships and emotional chaos, and that autism is marked by pervasive problems understanding social cues and communication2; borderline features rapidly shifting identity and relationship-triggered mood swings, while autism includes stable self-concept, sensory sensitivities, restricted interests, and literal communication that aren’t present in borderline; and borderline symptoms fluctuate dramatically with relationship stability while autistic traits remain consistent across contexts.
Social Communication Disorder
Social communication disorder is a DSM-5 disorder in which a person has significant ongoing difficulty using verbal and nonverbal communication appropriately in social situations. People with social communication disorder have trouble with the “pragmatic” aspects of language, or knowing how to use language effectively in social situations. They may have difficulty taking turns in conversation, figuring out how much detail to give, adapting their style of speech to suit the situation, understanding implied meaning or hints, interpreting non-verbal cues such as body language and facial expression, or knowing how to start, sustain or end conversations naturally. It affects life functioning and makes it difficult to develop friendships and relationships. The social communication problems of social communication disorder look nearly identical to the “Criterion A” features of autism. But unlike autism, people with social communication disorder do not have repetitive behaviors, restricted interests, sensory sensitivities or need for sameness and routine.
Social communication disorder is rarely diagnosed in place of autism, in part because autism provides eligibility for important services, insurance, educational supports, and legal protections that are not consistently available to social communication disorder. This creates significant practical motivations for families and clinicians to choose the autism diagnosis. Plus, autism has an evidence base, validated assessment tools, clear intervention protocols and a large supportive community with a neurodiversity-affirming culture, while social communication disorder does not. There is no community, very little research, no specific treatments and little professional awareness as it was only added to the DSM in 2013. The service delivery, insurance, and educational systems are all built around autism and not social communication disorder. And because both disorders require similar interventions for the social-communication difficulties, there’s little practical reason to differentiate between the two, especially when the boundary between these two (whether or not the restricted/repetitive behaviors are truly absent or just subtle) is often blurry and clinicians are often not sure the differentiation even matters.
Trauma-Related Disorders
Trauma-related disorders, especially those caused by early developmental trauma, profound neglect, or disrupted attachment, can look like autism with social withdrawal and avoidance of eye contact (defensive protection, not social processing issues), delays and challenges in communication (due to lack of language exposure or trauma effects on brain development), emotional dysregulation and meltdowns (due to emotional dysregulation, not sensory overload), repetitive self-soothing behaviors (anxiety management, not stimming), sensory sensitivities (hypervigilance, not sensory processing differences), and rigid need for routine (anxiety-driven safety-seeking, not cognitive processing style).
Severe early deprivation can result in “quasi-autistic” patterns that can be quite difficult to differentiate. The key differences are that trauma-related problems often improve a great deal in safe, nurturing environments with adequate psychological treatment; they often vary more with context (worse around triggers); they tend to be associated with recognizable adverse experiences rather than being present from very early infancy; and they do not involve the restricted interests and true deficits in processing social communication of autism.
Social Awkwardness (not a formal diagnosis)
Social awkwardness is not a psychiatric disorder. I am using it to refer to social ineptness without meaningful impairment that falls within what is considered normal or typical human variation. This can be mistaken for autism because both may involve limited friendships, preference for solitude, conversation difficulties, reduced eye contact, and intense interests, particularly fueled by online self-diagnosis culture and broad autism awareness. The key distinctions are that socially awkward individuals understand what they should do socially but find it difficult or uninteresting (versus genuinely not understanding unwritten rules), show significant improvement with practice and maturity, are more comfortable in specific contexts, lack the sensory sensitivities and restricted/repetitive behaviors required for autism diagnosis, and generally achieve life goals despite awkwardness rather than experiencing clinically significant impairment.
Other conditions to consider in the differential diagnosis of autism
Selective Mutism, Intellectual Disability (without autism), Stereotypic Movement Disorder, Attention-Deficit/Hyperactivity Disorder (ADHD), Schizophrenia Spectrum Disorders, Avoidant Personality Disorder, Attachment Disorders, Generalized Anxiety Disorder, Obsessive-Compulsive Disorder, and Rett Syndrome (a characteristic pattern of developmental regression after initial normal development, typically 6-18 months).
Additional Caveats
Misdiagnosis can go both ways. Comorbidity is possible and expected. Someone can be autistic and have maladaptive personality patterns, trauma histories, or anxiety disorders that complicate the presentation. Developmental context, response to relationships, and subjective experiences are all very important in looking beyond the surface presentation to understanding the meaning and functions of behaviors.
See also:
The schizotypy-autism overlap is a complicated clinical and scientific story; I am bypassing it in this post but plan to address it later.
Patients with BPD show disturbances of mentalization that can manifest as deficits of social cognition.
We could solve this issue if we focused on making context-specific theories about shared factors and personality traits of each of these rather than treating them as separate entities with separate etiologies and interventions and one single, APA/FDA-approved theory for each.
When people find the label that resonates and internalize it, then any change whatsoever in their life, personality system, or "symptom" set will threatens their very identity. Thus: a new DSM diagnosis with each new medical field interaction fuels identity crises. What is instead happening are extreme personality traits that have not been suitably actualized in a reliably appropriate manner, and so, manifest various DSM categories across life chapters.
Thus, rather than looking at broad categories like Schizoid PD, Borderline PD, ASD, and such and such, I believe it's more useful to look at many combinations (Forms) of underlying constructs like hyper-systemizing, alexithymia, high sensory sensitivity, extreme error detection (eg, inconsistency detection), elevated conscientiousness or openness, and so on. From these alone, it is not difficult to create a process model that spits out a different DSM category each time. If so, it shows we should focus on said traits as causal "unto themselves" rather than (weakly) emergent DSM categories that are unreliable from the start by virtue of their ever-changing natures. That is, Big 5 traits tend to be extremely stable across 5 year durations but schizophrenia does not have this same reliability.
You mentioned OCPD, which is strongly correlated with abnormally high conscientiousness and abnormally low openness to experience: hence, generalized behavioral rigidity. But rather than trying to "treat OCPD", I'm saying people should focus on increasing trait openness to experience in this one (literally n=1) example, which would necessarily lead to cognitive plasticity at the expense of over-control and over-inhibition. There are now dozens of long-term (multi-year) longitudinal studies showing that psilocybin increases trait Openness in dozens of DSM categories without meaningful safety effects.
Notice, however, I did NOT say "We should indiscriminately treat OCPD with ANY psychedelic". It is not even implied. Instead, I said people should focus on influencing the underlying personality traits unique to each individual rather than their diagnosis (hence, n=1), that just so happen to manifest many kinds of DSM categories every few months or years when aggregated in a sample. Modifying one's personality traits to change oneself is not a controversial idea.
An excellent source of theories about how such combinations of traits in the DSM manifest is Evolutionary Psychopathology by Del Giudice (2018). Unfortunately, people misinterpret the book as arguing DSM categories are themselves "evolutionary adaptations" or moral prescriptions. But he rejects this. Instead, the UNDERLYING personality traits (which have a biological basis) are possible adaptations-to-context (NOT society at large nor the entire gene pool), such that, when the context abruptly changes afterwards, become maladaptive and therefore manifest a new DSM category on each occasion. This suggests contexts, not individuals, are what become broken. Yet if persons and contexts are always changing then so will DSM categories. Therefore, we should focus on the suspiciously unchanging (highly reliable) contexts and personality traits correlated to suffering and breakdown, rather than ever-changing DSM categories diagnosed post-hoc that are apparently unmeasurable.
(Edited to reduce word count)
This is a great, very compassionate while still being skeptical. The word I hear most often is "neurodiverse". I have had similar experiences encountering people who self-diagnose in a way that might risk shutting down alternate possibilities. Referencing neurodiversity as a stand-in for the autism spectrum seems to have the appeal of being somewhat nonclinical while still authoritative, and also, perhaps, references a soft etiological claim, suggesting that the cause is rooted in determined neuroscience, possibly immutable. This has real implications for how people see themselves and their possibilities for change.
Aside from the consideration of different classification categories, for example, we could consider different contributing factors. Eg attachment issues (and not even necessarily formal trauma) can contribute to rigidity, repetitive soothing behaviors, certainly social awkwardness. But that is something that can be addressed! Whereas a "Neuro" label (sometimes, not always!) runs the risk of a sort of determined fatalism.