How Do Obsessive-Compulsive Disorder and Autism Spectrum Disorder Interact in Young People?

What you need to know

About 25% of youth with obsessive-compulsive disorder (OCD) also have autism spectrum disorder (ASD), while about 5% of youth with ASD also have OCD.
Youth with both OCD and ASD tend to have more severe impairments in daily functioning compared to those with only OCD or only ASD.
With treatment, youth with both OCD and ASD can make significant improvements, but may remain more impaired than those with OCD alone.

How common are OCD and autism together in youth?

Obsessive-compulsive disorder (OCD) and autism spectrum disorder (ASD) are two conditions that can significantly impact a young person’s life. While they are distinct disorders, research has found that they often occur together in children and adolescents. But just how common is this co-occurrence?

This study examined the medical records of nearly 8,000 young people aged 4-17 who had accessed mental health services in South London. The researchers found that among youth diagnosed with OCD, about 25% also had a diagnosis of ASD. This means that 1 in 4 young people with OCD also had autism.

Looking at it from the other direction, among youth diagnosed with ASD, about 5% also had a diagnosis of OCD. This was lower than expected based on previous research. The authors suggest this could mean OCD is being underdiagnosed in young people with autism, possibly because OCD symptoms are mistaken as being part of the autism itself.

These findings highlight how frequently OCD and autism co-occur in young people seeking mental health treatment. For clinicians, this underscores the importance of screening for both conditions when one is present.

How do OCD and autism interact?

The study revealed some key differences between youth who had both OCD and ASD compared to those with only one condition:

Earlier OCD diagnosis

Young people with both OCD and ASD tended to be diagnosed with OCD at a younger age (average 13.5 years) compared to those with OCD alone (14 years). This suggests that when autism is present, OCD symptoms may emerge or be recognized earlier.

More males affected

There were more males in the group with both OCD and ASD compared to the OCD-only group. This aligns with the fact that autism is generally more prevalent in males.

Greater impairment in daily functioning

One of the most striking findings was that youth with both OCD and ASD had significantly more difficulty with daily functioning compared to those with either condition alone. The researchers measured this using a standardized scale called the Child Global Assessment Scale (CGAS).

At the time of diagnosis, youth with both conditions scored an average of 44 on the CGAS. This was notably lower than the average scores for those with only OCD (49) or only ASD (49). Lower scores indicate greater impairment in areas like school, family relationships, and self-care.

This suggests that when OCD and autism occur together, there is a “double impact” on a young person’s ability to manage daily life. The challenges associated with each condition seem to compound each other.

More medication use

Young people with both OCD and ASD were much more likely to be prescribed psychiatric medications compared to those with either condition alone. Specifically:

68% were prescribed antidepressants (compared to 45% with OCD alone and 16% with ASD alone)
35% were prescribed antipsychotics (compared to 16% for both OCD alone and ASD alone)
27% were prescribed sedatives (compared to 11% with OCD alone and 21% with ASD alone)

This higher rate of medication use likely reflects the greater impairment and complexity of symptoms when OCD and autism co-occur.

How do youth with both conditions respond to treatment?

An important question is whether young people with both OCD and autism can benefit from mental health treatment. The study followed youth for an average of about 1.5 years after their initial diagnosis to see how their functioning changed.

The good news is that youth with both conditions did show significant improvement in their daily functioning after receiving treatment. On average, their CGAS scores increased by about 9 points.

However, their improvement was not as large as that seen in youth with OCD alone, who improved by an average of 12 points. By the end of the study period, youth with both conditions were still more impaired in their daily functioning compared to those with OCD alone.

Interestingly, by the end of the study, youth with both OCD and ASD were functioning at a similar level to those with ASD alone. This suggests that while treatment may not fully close the gap with typically developing youth, it can help those with both conditions reach a similar level of functioning as those managing autism alone.

What treatments did youth receive?

The study also looked at what types of treatments young people accessed:

Cognitive Behavioral Therapy (CBT)

CBT is considered the first-line psychological treatment for OCD in young people. About half of youth with OCD (both with and without autism) received CBT. While it’s encouraging that those with autism were equally likely to access CBT, the authors note that ideally, all youth with OCD should be offered this evidence-based treatment.

Medication

As mentioned earlier, youth with both OCD and autism were much more likely to be prescribed psychiatric medications compared to those with either condition alone. The high rates of medication use (particularly antidepressants) likely reflect the severity of symptoms in this group.

Length of treatment

Young people with both conditions tended to stay engaged with mental health services for longer (average 632 days) compared to those with OCD alone (441 days) or ASD alone (484 days). This extended treatment duration may reflect the complexity of managing both conditions simultaneously.

Conclusions

OCD and autism frequently co-occur in young people seeking mental health treatment. Clinicians should be alert to the possibility of both conditions being present.
When OCD and autism occur together, young people tend to have greater impairment in their daily functioning compared to those with either condition alone.
With treatment, youth with both OCD and autism can make significant improvements in their functioning, although they may not reach the same level as those with OCD alone.
More research is needed to develop and refine treatments specifically tailored for young people managing both OCD and autism.

This study highlights the importance of comprehensive assessment and personalized treatment planning for youth with co-occurring OCD and autism. While managing both conditions presents challenges, appropriate mental health care can lead to meaningful improvements in daily functioning and quality of life.