Sensory processing disorder vs. autism: How do they differ?

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Experts define SPD as difficulty detecting, modulating, and interpreting sensory stimuli to the point of causing trouble with daily routines and participation in activities.

It causes a person to experience reduced or heightened emotional, behavioral, or psychological responses to whatever sensory stimuli activated their sense(s) in the first place.

Sensory stimuli refer to any event or object that causes a person’s senses to detect it and elicit a response from the person. Some forms of stimuli can include:

• light
• touch
• sound
• heat

Internal processes can also activate one or more senses.

A person may perceive the stimuli through one or more systems within their body, including:

• auditory processing (hearing)
• taste
• touch
• visual processing (seeing)
• position or movement of a person’s head (vestibular)
• proprioceptive (stimuli from within a person)

SPD affects an estimated 5%–16% of children in the United States.

It occurs in about 90% of people living with ASD and about 50-64% of people living with attention deficit hyperactivity disorder (ADHD).

Isolated SPD can also occur independent of clinical conditions.

Unlike ASD or ADHD, SPD does not have an entry in the Diagnostic and Statistical Manual of Mental Disorders, 5th edition, text revision (DSM-5-TR). Experts still debate whether it should receive an entry.

Learn more about sensory processing disorder.

Symptoms

SPD causes an atypical reaction to sensory stimuli. A person may experience reduced or heightened emotional, behavioral, or psychological responses to stimuli that most other people would not react strongly to.

It can cause a person to experience a fight, flight, or freeze response. This can present as:

• withdrawal
• aggression
• a preoccupation with the expectation of sensory input

One or more of three behavioral patterns often occur, which include:

• Sensory under-responsiveness: People may not respond or show low response to sensory cues, may mouth objects, appear uninterested, or daydream frequently.
• Sensory over-responsiveness: People may have an exaggerated response to stimuli compared to other people. This may include a fearful or anxious reaction to movements, such as changing head positions, not having both feet on the ground, or touching. They may also have a strong reaction to certain foods or avoid social situations.
• Seeking out sensory input: People may constantly touch, crash into objects or people, move, and have limited or no awareness of personal space or boundaries. It can lead to concerns for safety or awkward, clumsy movements.

ASD is a neurological and developmental disorder. It can affect how a person behaves, interacts with others, learns, and communicates. A person may receive a diagnosis at any age, but it often occurs when a person is still a young child.

ASD is a spectrum disorder. This means there is a wide range in the type and severity of symptoms a person experiences.

ASD can affect any race, gender, or ethnicity. However, it is four times more likely to occur in children assigned male at birth compared to those assigned as female. Other risk factors may include:

• having older parents
• siblings with ASD
• complications at birth
• genetic or chromosomal conditions, such as fragile X syndrome or tuberous sclerosis

In 2020, an estimated 1 in 36 eight-year-old children received an ASD diagnosis, according to the Centers for Disease Control and Prevention (CDC).

Learn more about autism.

Symptoms

A child typically starts to show symptoms by age 2.

Symptoms may include:

• repetitive behaviors
• limited interests
• trouble with communicating with others
• difficulty interacting with others

Symptoms often interfere with a person’s ability to function at home, school, or work.

Read about autism symptoms in a 3-year old.

The exact link between SPD and ASD remains unclear.

Data suggests that about 90% of people living with ASD also have SPD. However, other disorders, such as ADHD, also have a high prevalence rate of SPD associated with it. SPD can also occur on its own.

According to an older study from 2013, children with SPD had abnormalities in areas of white matter located in the posterior regions of the brain that are involved in sensory processing.

Another older study from 2014 compared the brains of children with ASD to those with SPD. They found similar white matter disruption in the sensory pathways and divergent connectivity in the socioemotional pathways. This indicates that SPD can occur outside of the diagnosis of ASD.

More recently, a 2017 study showed larger gray matter volumes in early sensory regions of the brain in children living with both disorders. These higher volumes may be associated with unusual sensory processing of tactile, auditory, visual, and taste or smell modalities.

These studies indicate that shared abnormalities in the gray or white matter of the brain responsible for sensory processing may indicate why ASD often occurs along with SPD. The differences, though, may show why it can occur with other disorders, such as ADHD, or on its own.

Both SPD and ASD have different diagnostic criteria.

Sensory processing disorder

Currently, SPD diagnosis depends on the presence of difficulties in detecting, modulating, interpreting, or organizing sensory stimuli to the point of interference with daily activities or functions.

It can occur alongside a comorbid condition, such as ASD or ADHD, or it may occur independently from any condition.

Despite generally accepted diagnostic criteria within the medical field, there is no entry in the DSM-5-TR for SPD. This can lead to variations in who receives a diagnosis and missed diagnoses.

Autism

For a healthcare professional to diagnose ASD, a person must exhibit persistent deficits in each of the three areas of social communication and interaction as well as at least two of four types of restricted, repetitive behaviors.

The three areas of social communication and interaction deficits include:

• social-emotional reciprocity
• nonspeaking communicative behaviors
• developing, maintaining, and understanding relationships

Repetitive or restricted behaviors include:

• repetitive motor movements
• hyper or hyporeactivity to sensory input or unusual interest in sensory aspects of the environment
• highly restricted, fixated interests
• insistence on sameness, ritualized patterns of verbal or nonspeaking behavior, or inflexible adherence to routines

Management options can differ between SPD and ASD.

Sensory processing disorder

Similar to diagnostic criteria, the management of sensory processing disorder is not consistent across all settings.

Management approaches may include:

• mental health professionals to address behavioral issues
• off-label medication use, such as propranolol to help dampen reactivity or serotonin-norepinephrine reuptake inhibitors (SNRIs) for tactile issues
• sensory integration therapy that stimulates and challenges the senses while reinforcing adaptive, functional responses

Read more about treatment for sensory processing disorder.

Autism

Management of ASD involves a multifaceted approach. Experts recommend beginning to implement strategies shortly after diagnosis.

Management approaches often involve combinations of different modalities that may include:

• medications to help with certain behaviors and responses, such as aggression or repetitive actions
• behavioral or psychological interventions
• supports in school to aid learning

The following sections provide answers to some frequently asked questions about SPD and ASD.

Can you have sensory processing issues and not be autistic?

About 90% of people living with autism develop or have sensory processing issues. However, they can also occur in other disorders, such as ADHD, or on their own.

What are the 4 types of sensory processing disorders?

SPD typically involves either an over or under reaction to sensory stimuli. The stimuli may include touch, hearing, smell or taste, internal processes, or vision.

Learn about sensory overload.

Can kids grow out of SPD?

Children with SPD may grow out of the condition as they get older. However, this is not well understood or studied.

ASD and SPD often occur together, but they are each their own condition.

ASD is a bit more established in scientific and medical literature with clear diagnostic criteria, treatments, and symptoms.

SPD lacks firm diagnostic criteria and consistent or effective management options and can include varied symptoms.

Both can occur on their own and can cause challenges for learning, development, and social or peer interactions.