Autism and schizophrenia are different conditions, although some people live with both.

Before autism spectrum disorder (ASD) became a distinct diagnosis in 1994, it was considered part of schizophrenia spectrum disorder (SSD).

This meant that if a child showed symptoms of autism, health professionals would give them a diagnosis of childhood-onset schizophrenia.

Now, clinicians and researchers have a clearer understanding of the differences between the two diagnoses, keeping in mind the similarities they might share.

Schizophrenia vs. autism

Autism wasn’t conceptually separated from SSD until 1971. The change wasn’t technically acknowledged in the Diagnostic and Statistical Manual of Mental Disorders (DSM) until the 4th edition was released in 1994.

Nowadays, each condition has different diagnostic criteria. You need to meet these criteria in order to get a diagnosis from a health professional. These criteria include causes, symptoms, age of onset, and, in some cases, need for symptom management.

Causes

The specific causes of ASD and schizophrenia have not yet been established. Experts believe a combination of factors is involved in both conditions.

Some common possible causes of autism include:

  • genetics and biology
  • older paternal age at the time of conception
  • exposure to toxins during pregnancy
  • history of autoimmune disease or diabetes in the pregnant parent
  • childbirth complications
  • atypical brain growth due to different causes

Schizophrenia may have genetic causes, just like autism. Other possible causes or contributing factors include:

  • pregnancy and childbirth complications
  • traumatic childhood experiences
  • early exposure to particle pollution and excess noise
  • social isolation or neglect
  • maternal age of less than 19 years or more than 40 years
  • structural brain differences

Some causes, like advanced maternal age and pregnancy complications, may be contributing factors to both autism and schizophrenia.

Symptoms

Although sometimes confused with one another, autism and schizophrenia have different features.

“Autism is defined by the presence of social communication deficits and restricted and repetitive behaviors,” explains Jessica Myszak, PhD, a psychologist and director of the Help and Healing Center in Glenview, Illinois.

Not everyone who’s autistic experiences the same features or has the same needs for support, though.

According to the latest edition of the DSM, there are three main levels of support that autistic people may fall into:

  • level 1 requires some support
  • level 2 requires substantial support
  • level 3 requires very substantial support

Based on this, some common symptoms of autism may require different levels of support, depending on the person. These include:

  • difficulty establishing eye contact
  • differences in speech development compared with nonautistic children of the same age
  • preference for following the same routines
  • increased or decreased reactions to sensory experiences, including touch and sound
  • difficulty matching speech and behavior to the situation
  • hard time expressing emotions or perceiving other people’s emotions
  • focused or narrow interests
  • stimming or self-soothing repetitive behaviors like hand flapping
  • disrupted sleep patterns

By comparison, Myszak describes schizophrenia as, “a brain disorder, which can include delusions, hallucinations, difficulty thinking, communication difficulties, and other symptoms.”

Schizophrenia symptoms are grouped into three categories:

Negative symptoms of schizophrenia are different from signs of autism. But sometimes, they are confused with each other.

flat affectreduced emotional expressions
disorganized speech or reduced verbal communicationatypical communication patterns
low energy or motivationless spontaneous social interaction
difficulty focusing on interactionsdifficulty connecting to peers or surroundings

“It is difficult to distinguish between [some] SSD symptoms and autism symptoms in clinical practice,” says Elizabeth Lombardo, PhD, author, keynote speaker, and psychologist in Chicago. “Sensory difficulties in people with autism, for example, could be mistaken as hallucinations in schizophrenia, with severe therapeutic implications.”

Onset

An important difference between autism and schizophrenia is the time when most symptoms first develop.

Usually, autism signs appear earlier than those of schizophrenia.

“Autism signs develop early in childhood, but symptoms [of schizophrenia] often do not appear until adolescence at the earliest,” Lombardo explains.

Sometimes an autism diagnosis isn’t reached until adolescence or early adulthood, though. This may be the case for autistic people who don’t need substantial support.

On rare occasions, schizophrenia is diagnosed in children. With childhood-onset schizophrenia, symptoms are identified before age 13.

Outlook

Autism is a neurodevelopmental disorder that manifests with moderate or significant behavioral and cognitive differences.

Autism is a wide spectrum. In some cases, it may require substantial support.

Autism cannot be cured. Many advocates emphasize that it doesn’t need to be cured, either.

“[Autism] can be significantly impairing, limiting ability to hold a job and live independently. But many autistic individuals can also be very successful in work due to having a unique perspective and focus,” Myszak says.

Schizophrenia is considered a psychiatric disorder that requires symptom management. Without treatment, you might have a hard time in different aspects like work and relationships.

Getting a correct diagnosis is crucial. This is because, as Myszak points out, schizophrenia, “is most commonly treated with medication, and with consistent medication, many symptoms can be significantly improved.”

This isn’t the case with autism. If an autistic person gets a misdiagnosis, they could be improperly medicated.

“Numerous therapies… can be helpful [for autism] — occupational therapy, speech therapy, and applied behavior analysis (ABA),” Myszak says. “[ABA] is often recommended for young children, but is controversial with autistic adults. Most autistic children and adults benefit from adaptations and accommodations.”

Is schizophrenia part of the autism spectrum?

No. Autism isn’t part of the schizophrenia spectrum and schizophrenia isn’t part of the autism spectrum.

Sometimes autistic people experience symptoms of psychosis if they also live with schizophrenia. Psychosis is not a formal symptom of autism.

Psychosis may be difficult to identify if the autistic person has a limited ability to communicate, though.

In some cases, if a young autistic person experiences psychosis, a clinician may assess for a diagnosis of childhood-onset schizophrenia.

Dual diagnosis: Can you have both autism and schizophrenia?

Yes. Symptoms of autism and schizophrenia usually occur separately, but an individual can have both.

“There is a genetic component for both autism and schizophrenia, with both of these conditions running in families,” Myszak says. “These two conditions can co-occur.”

Autistic people are 3.55 more likely to receive a schizophrenia diagnosis than nonautistic folks, Myszak says, citing a 2018 review.

Experts aren’t sure if this is because they live with both conditions or they’re misdiagnosed, according to a 2019 review.

Let’s recap

Autism and schizophrenia are two different conditions with separate criteria needed for diagnosis.

They may share some similarities when it comes to contributing factors and symptoms. The physiological cause of these symptoms isn’t the same, though.

Although rare, it’s possible for someone to live with both conditions.

In general, schizophrenia requires professional treatment. On the other hand, autism may need different levels of support and accommodations, depending on the needs of the autistic person.