The line between autism and schizoid personality disorder can sometimes be blurry, but a closer look reveals the difference may lie in social capacity versus motivation.

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Have you or someone close to you always felt that it’s:

  • a challenge to connect with others
  • preferable to spend lots of time alone
  • or feel emotionally vested in circumstances

If so, you may be curious about autism spectrum disorder (ASD) and schizoid personality disorder.

If you’re already familiar with these conditions, you may wonder what the similarities and differences are. They can at first seem identical, but there are key differences. So how can you tell one from the other?

Autism diagnoses exist on a spectrum, meaning that the symptoms vary in type and degree. While severe autism may include learning disabilities, high functioning autism can have elevated learning capacities. Autism is collectively underpinned by difficulties with social behaviors.

As one of 10 different types of personality disorders, schizoid personality disorder is unique from ASD. Personality disorders similarly disrupt people’s ability to bond with others, solve problems, or adapt to changing environments. Personality disorders resemble the basic structure of autism but aren’t quite as complex.

Autism symptomsSchizoid PD symptoms
repetitive behaviors/speechodd or eccentric speech
inflexibility/strict routinesconcrete/obsessional thinking
special, fixed interestsunusual preoccupations
social withdrawalsocial withdrawal
emotionally detachedemotionally detached
sensory issuesunusual perceptual experiences

Although both disorders have a list of defining symptoms, there is a key difference between them.

Generally, ASD involves challenges in social capacity due to early neurodevelopmental challenges. On the other hand, the focus of schizoid personality disorder involves challenges in social motivation, according to this 2021 study.

So what’s the difference between social capacity and social motivation?

Social capacity in autism

In autism, there are unique neurodevelopmental challenges that begin in early childhood. According to Autism SA, signs of autism can be identified as early as 18 months. Childhood caretakers and pediatricians would likely have noticed developmental challenges early in life.

Broadly, neurodevelopmental challenges in autism affect the way folks:

  • communicate
  • interact
  • behave

Some effects are difficulties with:

Since these skills are essential components of social function, underdevelopment results in difficulties with friendships and romance throughout life.

Such challenges don’t mean an autistic person can’t start or maintain relationships. Rather, like any relationship, it will take intention and work to understand each other.

Social motivation in schizoid personality disorder

In schizoid personality disorder, neurodevelopmental challenges and their effect on social capacity aren’t considered a defining factor. The focus is rather on social motivation. A person who’s socially motivated seeks social interaction and the formation of relationships.

Lacking social motivation differs from lacking social capacity because motivation signifies desire, whereas capacity signifies capability.

For example, an autistic person can be strongly motivated to pursue intimacy and connection. In contrast, someone living with schizoid personality disorder might often be content alone.

While it’s generally accepted that autistic folks are socially motivated, this notion is not completely certain.

Research from 2018 highlighted the “social motivation hypothesis or the potential for autism to also be defined by a lack of social motivation. This proposition could challenge whether or not autism and schizoid personality disorder truly differ in this regard.

Like most personality disorders, the cause of schizoid personality disorder is currently unknown. Kamron Fariba and Vikas Gupta, authors of “Schizoid Personality Disorder,” speculate that the condition may be:

  • inherited
  • related to environmental factors
  • involve brain function changes

Diagnosing schizoid personality disorder

The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria for schizoid personality disorder requires four or more of the following symptoms:

  • almost always chooses solitude and solitary activities
  • avoidance of close relationships and lack of desire for them
  • lack of close friends other than immediate family
  • lack of interest in sex with others
  • emotional detachment or lack of emotional expression
  • indifference to praise or criticism
  • experiences minimal pleasure from activities

Symptoms must occur over a long time and in multiple settings. Notably, the criteria are shorter and simpler than the autism criteria.

Diagnosing autism

According to the DSM-5, an autism diagnosis includes challenges that persist throughout life in three of the following areas across multiple settings:

  • challenges with social and emotional reciprocity (e.g., cannot hold a basic back and forth conversation or respond to social interactions)
  • challenges with nonverbal communication (e.g., trouble with eye contact, body language deficit)
  • challenges in understanding, maintaining, and developing relationships

It must also include two of four types of restricted and repetitive behaviors as follows:

  • repetitive movements, phrases, or characteristic movements (e.g. lining up objects)
  • inflexibility toward routines, small changes, transitions
  • restricted or fixated interests
  • under or overactivity to senses (e.g., indifference to pain, excessive smelling of objects)

Furthermore:

  • Symptoms must have begun in early childhood
  • Symptoms must impair social, occupational or other important areas of function

Given that autism and schizoid personality disorder resemble each other, they can be mistaken. A 2014 study found a strong relationship between several traits in both conditions. The overlap was particularly true for traits that result in disorganized social relationships, such as odd speech, beliefs, or behavior.

Generally, here are some reasons why the two disorders can be mistaken:

  • schizoid personality disorder can resemble mild cases of autism in adults
  • autism can outwardly appear as schizoid personality disorder
  • autism includes most symptoms of schizoid personality disorder

If they do occur, diagnostic mistakes are likely to be made in adulthood. This is because children are regularly evaluated by healthcare professionals for delays in developmental milestones including social behaviors.

So, the key traits of autism occurring in childhood, such as difficulty with reduced eye contact, limited speech, and repetitive behaviors, are likely to be detected early in life.

In schizoid personality disorder, these traits are observed not as difficulties in performance but lack of desire to do so.

The notion that social motivation may also be reduced in those living with autism challenges whether or not both conditions are truly independent.

Further, this 2021 study noted that autistic traits may outright precede cases of schizoid personality disorder. Though if they did, it says they would likely be mild traits.

It’s possible that schizoid personality disorder could ultimately end up on the autism spectrum in the future.

Since its main causes are poorly understood, it might involve some degree of neurodevelopmental changes. Regardless, it’s currently recognized as an independent condition.

Ultimately, the resemblance between both conditions suggests that they can indeed co-exist.

But if you show signs of autism, schizoid personality disorder likely wouldn’t be co-diagnosed.

Autism is a more complex condition that affects multiple aspects of your behavior and function. It doesn’t only involve skills related to social function, but also includes unique characteristics like:

  • restricted and repetitive behaviors
  • fixed interests
  • inflexibility

Schizoid personality disorder is more likely to be recognized in adulthood, whereas autism is almost always first recognized in childhood. This is an important and defining distinction. While both disorders resemble each other, this makes them distinguishable.

The conditions are similar enough that the line between autism and schizoid personality disorder traits is sometimes rather blurry. What is clear, is that both are manageable with:

If you think you may be living with either condition, it’s best to speak with a mental health professional. Psychologists are trained to diagnose and treat personality disorders as well as autism and can help you get any care that you may need.