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The short answer to this frequently asked question is a resounding ‘Yes!’. One absolutely can.

But, if you’re like me (Autism + ADHD), the short answer only leads to more questions. So, let’s work through this together for better context.

From mutually-exclusive to overlapping

For many years, autism and ADHD were thought to be mutually exclusive because diagnostic guidelines didn’t allow both at once. Growing research and clinical insight, however, revealed significant overlap, prompting a major shift in 2013: both conditions can now be diagnosed together. This updated view reflects our deeper and ever-expanding understanding of neurodevelopmental conditions, showing that individuals can have unique combinations of traits (and that recognising this complexity leads to better, more personalised support.). Increasingly, clinicians and researchers, including us at the Neurodiversity Centre working within Gillberg’s ESSENCE framework, recognise that these conditions are best understood not as isolated ‘boxes,’ but as overlapping profiles within the broader landscape of childhood neurodevelopment.

Autism & ADHD: Distinct, but overlapping neurodevelopmental conditions

Autism and ADHD are both recognised as neurodevelopmental conditions, meaning they affect how the brain develops and functions from birth. While autism is known for challenges with social interaction and communication, ADHD is marked by differences in attention regulation, impulsivity, and sometimes hyperactivity. Despite these differences, there’s a lot of overlap. Many people show traits of both: difficulty focusing, navigating social situations, or managing routines. Recent studies reveal that co-occurrence is more common than once thought, with nearly half of people with autism also showing ADHD traits, and vice versa.  

What the latest research shows

Research shows that the prevalence of having both ADHD and autism varies widely depending on age and group studied. In the general child and school-aged population, about 0.5–1.2% have both diagnoses. However, within autistic communities, rates are much higher, with studies having found that 26–40% also meet criteria for ADHD, and one major analysis reported the overlap as high as 38.5%. Conversely, recent studies indicate that between 9% and 15% of individuals diagnosed with ADHD also meet the criteria for autism, with some research showing even higher rates (up to 30%) depending on the assessment methods and the population studied.

We are likely to see an increase in reported rates of co-occurring ADHD and autism in future as our understanding and awareness of these conditions continue to grow. Over the past decade, research, improved diagnostic tools, and shifting clinical guidelines have led to more frequent recognition of both conditions, especially when they appear together. This trend suggests that as clinicians and educators become even better equipped to identify the overlapping and unique traits of each, the rates of dual diagnosis will likely rise further. This doesn’t necessarily mean the actual prevalence is increasing; rather, our ability to recognise and diagnose these co-occurring neurodevelopmental differences is improving.

Why they co-occur so often

It is believed that autism and ADHD co-occur so frequently because they share genetic and neurological roots. Research shows that families with a history of either condition often see both manifesting across generations, hinting at shared genes. Brain studies suggest that similar areas, including those involved in attention, impulse control, and social interaction, may develop differently or function uniquely in both groups. Furthermore, children’s developmental paths sometimes reveal mixed patterns: difficulties with focus and social engagement can arise together, making it harder to separate one diagnosis from the other.

What this means for individual assessment, support and intervention

Recognising that ADHD and autism both can be present shapes how professionals assess and support individuals. Accurate diagnosis depends on understanding the similarities and differences, and using evidence-based tools designed to catch both sets of traits. For those with dual diagnoses, support plans need to be flexible and personalised, accounting for unique strengths and challenges. Ultimately, understanding the overlap helps families, educators, and clinicians provide care that allows each individual with their own specific set of needs to reach their full potential.

This diagnostic evolution illustrates how our understanding of neurodevelopmental conditions continues to evolve. What was once seen as impossible (having both autism and ADHD) is now recognised as common. This serves as a reminder that diagnostic categories are human constructs designed to help us understand and support individuals, rather than fixed truths about how brains must function.

The shift also reflects growing recognition that neurodiversity encompasses a wide spectrum of brain differences that can co-occur and interact in complex ways. Rather than fitting neatly into separate boxes, many individuals experience multiple neurodevelopmental differences simultaneously.

This historical perspective emphasises that our current understanding, while much more nuanced, will likely continue evolving as research advances and our knowledge deepens. What remains constant, however, is the importance of recognising and supporting each person’s unique profile of strengths and challenges, regardless of how many diagnostic categories they may cross.

References

Author Leandra De Waal (Counselling Psychologist)

More posts by Leandra De Waal (Counselling Psychologist)