OCD and autism: How can you tell the difference?

It is normal to wonder

When your child with autism suddenly demonstrates a new repetitive behavior, it is normal to ask yourself: Is this OCD (Obsessive Compulsive Disorder)? Parents are justifiably concerned if a new stim appears, or if their child seems to develop a new compulsive habit, such as leaving the house, going back in, and then walking out the door again every time you want to go out.

Autistic symptoms and OCD can look similar

Autism Spectrum Disorder (ASD) and OCD are two different conditions, however, it is true that some symptoms of autism overlap with those of other disorders, such as OCD, and can look similar (Højgaard et al. 2016). For example, people with autism and people with OCD may display repetitive behaviors, obsessive behaviors and severe anxiety. Both children with OCD and children with autism can become very rigid and resistant to change. A key difference between OCD and autism is the purpose or motivation for the behavior.

Repetitive behaviors as a venting mechanism

For example, a child with autism may demonstrate that he is feeling anxious or excited by lining up items such as small cars, by playing with an object at the side of his eye, or by flapping his hands or arms while hopping in place or running in circles. Verbal adults with autism have enlightened us as to the meaning of such repetitive behaviors. They explain that these actions can soothe their anxiety and give them a feeling of control in an uncontrollable situation.

When a parent sees their child with autism lining up toy cars, they may think this looks like an OCD behavior. If someone breaks the line, the child may go straight back to building it again, in an almost robotic manner. However, the child may also suddenly drop the behavior and move to another activity without any specific reason, which is not typical of someone with OCD.

OCD symptoms are different

While most children with autism have repetitive movements or vocal tics that show us when they are feeling anxious or excited, the source of the obsessive habits of someone with OCD is different. When someone with OCD feels driven to fill their life with repetitive patterns this is part of a mental process. Their compulsive behaviors have complicated motives which are not reasonable and which, in themselves, are part of the diagnosis.

A child with OCD will explain why she needs something to be done exactly as she demands and will not be able to move from this rigid behavior. For example, she may be unable to eat her yogurt if there is a small piece of metal foil stuck to the rim of the container. No amount of coaxing or patient reasoning from the parent will make any difference or be able to reduce the child’s anxiety.

Stimming vs. OCD: Different motivations

OCD children are constantly bombarded with terrifying thoughts about imminent danger which cause a state of panic leading to obsessive behaviors. Children with autism do not tend to think about their stim as a purposeful action.

Professor Temple Grandin, a knowledgeable and trustworthy expert on autism, says: “Most kids with autism do these repetitive behaviors because it feels good in some way” (Grandin, 2011). This statement is a powerful description of the difference between a person with autism who stims and the compulsive rituals of someone with OCD.

Another way to observe differences

In addition to asking a child about his motivations and fears, you may be able to make the distinction between a repetitive act in OCD and a stim in autism by trying to stop it. In our experience, if you interrupt an autistic child’s repetitive routine he will not show distress and you may be able to redirect his attention with a new object or invitation, but he will probably develop a new stim. However, since the repetitive behaviors of a child with OCD are related to deep fears, if you were to try to stop their routine, they could become extremely distressed to the point of having a panic attack.

Monitor the behavior and consult a doctor

In conclusion, when a person with autism shows a new stimming behavior, this can indicate an increase in their anxiety level, or it may be a developmental stage, or an indicator of OCD. When someone with OCD displays repetitive behaviors, these patterns are the result of sophisticated thinking, they have a crucial purpose for that person and are never isolated from their purpose. Monitoring the new repetitive behavior by taking notes and possibly filming it, will be helpful when you talk with the person’s physician. Your physician will be the best person to advise you about whether this new situation requires further attention.

We also recommend Mendability for children with autism and OCD. Mendability delivers Sensory Enrichment Therapy (SET) online. The benefits of SET for children with autism are clinically proven.


  1. Grandin, Temple PhD. “Why Do Kids with Autism Stim?Autism Asperger’s Digest, November/December 2011.
  2. Højgaard, Davíð R. M. A., Gudmundur Skarphedinsson, Judith Becker Nissen, Katja A. Hybel, Tord Ivarsson, and Per Hove Thomsen. 2016. “Pediatric Obsessive-Compulsive Disorder with Tic Symptoms: Clinical Presentation and Treatment Outcome.” European Child & Adolescent Psychiatry, December. doi:10.1007/s00787-016-0936-0.
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