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.
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. In schizoid personality, the person typically understands social conventions but simply isn’t motivated to engage with them. They withdraw from genuine disinterest. 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, unusual perceptual experiences, and difficulties with close relationships. Unlike schizoid personality (which involves simple disinterest in relationships), schizotypal includes strange ways of thinking and perceiving the world. People with schizotypal personality might believe in telepathy, feel they have special powers, think random events have special meaning for them personally, or have unusual perceptual experiences (like feeling a presence in the room or hearing whispers). They typically have few close friends, experience social anxiety that doesn’t improve with familiarity, and 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 comes from magical thinking, paranoid ideas, and perceptual distortions.
Obsessive-Compulsive Personality
Obsessive-compulsive personality describes people who are preoccupied with orderliness, perfectionism, and control. These individuals are rigid rule-followers who want things to be done “the right way,” have difficulty delegating tasks, and get caught up in details and lists to the point where they lose sight of the main goal. They tend to be workaholics who neglect leisure and friendships, are inflexible about matters of morality or ethics, and are often stubborn and controlling. Both obsessive-compulsive personality and autism can involve rigid adherence to routines, rules, and specific ways of doing things. In obsessive-compulsive personality, the inflexibility comes from anxiety about loss of control. The person is trying to, consciously or unconsciously, manage anxiety through control and perfectionism. In autism, the need for sameness and routine serves different functions. It provides predictability in a world that feels confusing or it helps with sensory regulation rather than anxiety-driven perfectionism.
Social Phobia
Severe social anxiety is an intense, persistent fear of social situations where a person might be judged, embarrassed, or humiliated. Social anxiety disorder involves overwhelming fear that interferes with daily life. People with this condition worry excessively about saying something stupid, looking foolish, or being rejected. They often avoid social situations entirely, which can lead to isolation, difficulty maintaining employment, and problems forming relationships. Both social anxiety and autism involve social difficulties and withdrawal. Social anxiety usually improves significantly in comfortable, safe environments (like with close family or friends), while autistic social differences tend to be more consistent across all contexts.
Borderline Personality
Borderline personality disorder involves intense emotional instability, unstable relationships, fear of abandonment, and a shifting sense of self, with people experiencing rapid mood swings and chaotic relationships that alternate between idealization and devaluation of others. While it can resemble autism through social difficulties, emotional dysregulation, rigid thinking, and feeling different from others, the key distinctions are that borderline centers on intense relationship preoccupations and emotional chaos, whereas autism involves genuine difficulty understanding social cues and communication; 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 condition in DSM-5 where someone has significant, ongoing difficulty using verbal and nonverbal communication appropriately in social contexts. People with social communication disorder struggle with the “pragmatic” aspects of language, that is, knowing how to use language effectively in social situations. They may have trouble understanding when to take turns in conversation, knowing how much detail to give, adjusting their speaking style for different situations, understanding implied meanings or hints, picking up on nonverbal cues like body language and facial expressions, and knowing how to start, maintain, or end conversations naturally. This makes forming friendships and relationships difficult and affects life functioning. The social communication problems in social communication disorder look nearly identical to the “Criterion A” features of autism. However, unlike autism, people with social communication disorder don’t show repetitive behaviors, restricted interests, sensory sensitivities, or the need for sameness and routine.
Social communication disorder is rarely diagnosed in favor of autism primarily because autism provides access to critical services, insurance coverage, educational support, and legal protections that social communication disorder does not reliably offer, creating strong practical incentives for families and clinicians to prefer the autism diagnosis. Additionally, autism has an established evidence base, validated assessment tools, clear intervention protocols, and a large supportive community with a neurodiversity-affirming culture, while social communication disorder has none of these. It has no community, minimal research, no specific treatments, and little professional awareness since it was only introduced in the DSM in 2013. Service delivery, insurance, and educational systems are built entirely around autism rather than social communication disorder, and since both conditions require similar interventions for social-communication difficulties, there’s little practical incentive to make the diagnostic distinction, especially when the boundary between them (whether restricted/repetitive behaviors are truly absent or just subtle) is often unclear and clinicians are often unsure the distinction really matters.
Trauma-Related Disorders
Trauma-related disorders, particularly from early developmental trauma, severe neglect, or disrupted attachment, can mimic autism through social withdrawal and avoidance of eye contact (defensive protection rather than social processing difficulties), communication delays and difficulties (from lack of language exposure or trauma’s impact on brain development), emotional dysregulation and meltdowns (from emotional dysregulation rather than sensory overload), repetitive self-soothing behaviors (anxiety management rather than stimming), sensory sensitivities (hypervigilance rather than sensory processing differences), and rigid need for routine (anxiety-driven safety-seeking rather than cognitive processing style).
Severe early deprivation can create “quasi-autistic” patterns that can be genuinely difficult to distinguish. The critical distinctions are that trauma-related difficulties typically improve significantly in safe, nurturing environments and with adequate psychological treatment, show more variability across contexts (worse with triggers), are tied to identifiable adverse experiences rather than present from earliest infancy, and lack the restricted interests and genuine social communication processing deficits of autism.
Social Awkwardness
Social awkwardness refers 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
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:
Society could solve much if this issue if they focused on making context-specific theories about shared factors and personality traits of each of these constructs 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 hence internalize it, but then any change whatsoever in their life, personality system, or "symptom" set occurs, then this automatically threatens their very identity. Thus: a new DSM diagnosis with each new medical field interaction also causes an identity crisis. What is instead happening are extreme personality traits that have not been suitably actualized in a reliable manner, and so, manifest various DSM categories across different 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 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, this is useful because it proves we should focus on said traits as causal 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, cognitive rigidity. But rather than trying to "treat OCPD", I'm saying people should here focus on increasing trait openness to experience in this one (literally n=1) example, which would 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 of DSM categories without meaningful safety effects.
Notice, however, I did NOT say "We should indiscriminately treat OCPD with psilocobyn". It is not even implied. Instead, I said people should focus on influencing the underlying personality traits unique to each individual person (hence, n=1), that just so happen to manifest many kinds of DSM categories every few months or years. Modifying one's personality traits, especially one at a time, with the goal of changing oneself is not a controversial idea.
An excellent source of theories about how such combinations of traits shared across the DSM can manifest is Evolutionary Psychopathology by Del Giudice. Unfortunately, people misinterpret the book as arguing DSM categories are themselves "evolutionary adaptations". But he explicitly rejects this. Instead, the UNDERLYING personality traits are possible adaptations-to-context (NOT society), 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. But 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, rather than ever-changing DSM categories diagnosed post-hoc that are apparently unmeasurable.
I'm so glad you made this post. I see this so much and it can be so discouraging to see ASD diagnoses applied indiscriminately, particularly because the ASD interventions aren't helpful if the individual's symptoms are much better explained by another more appropriate diagnosis. A big red flag is the criterion B - many people just don't meet that despite being given the diagnosis.