This article, written by Dr. Darren O’Reilly and reviewed by Dr. Wenn Lawson, is intended for informational purposes only and does not constitute clinical advice. Neurodevelopmental conditions are highly variable in how they present, and the experiences described here will not apply to every individual. If you have questions about your own or a loved one’s neurodevelopmental profile, consult a qualified healthcare professional.

How Adult ADHD May Present

Adult ADHD often looks different from childhood hyperactivity. Physical restlessness may be replaced by internal mental restlessness, racing thoughts, or chronic distractibility. It is important to note that ADHD presents across different subtypes, including inattentive, hyperactive-impulsive, and combined, and not all individuals will experience hyperactivity.

Adult ADHD symptoms may include:

  • Difficulty sustaining attention
  • Disorganisation
  • Forgetfulness
  • Impulsive decision-making, and
  • Problems completing long-term tasks

Executive functioning differences, such as difficulties with planning, time management, and working memory, are frequently reported in ADHD in adulthood. Some adults describe a pattern of starting projects enthusiastically but struggling with follow-through, or feeling chronically overwhelmed despite strong intellectual abilities.

How Autism May Present in Adults

Autism in adulthood can be subtle, particularly in individuals who have developed compensatory strategies. Social camouflaging—consciously or unconsciously masking autistic traits to meet social expectations—has been documented in research, particularly among women (Hull et al., 2021). This masking can delay recognition for years.

Common adult autism traits may include:

  • Difficulty interpreting nonverbal social cues
  • Preference for predictable routines
  • Deep, focused interests
  • Sensory sensitivities to sound, light, or texture
  • Social fatigue after prolonged interaction

Sensory processing differences are documented in research as a frequently reported feature of autism that persists into adulthood (Marco et al., 2011).

For some adults, understanding sensory sensitivity retrospectively may help explain lifelong discomfort in certain environments.

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Dr. Wenn Lawson speaks about what it can be like navigating adulthood with both autism and ADHD, the impact of receiving a diagnosis, and the self-care and compassion that are necessary for success.

This webinar is provided in partnership with the World Autism Organisation

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The mean age of autism diagnosis in the US and UK is 4 to 5, though later diagnoses do occur (Zwiagenbaum et al., 2019). Age at diagnosis depends upon variables such as symptom severity, socioeconomic status, and initial parental concerns or misidentification of symptoms as behavioral issues (Fountain et al., 2011; Shattuck et al., 2009). Typically individuals with more severe symptom challenges receive an autism diagnosis early in life compared to those with subtle symptomatic differences (Zwiagenbaum et al., 2019; Edelson et al., 2020). Those diagnosed later in life are thought to have less severe symptoms and a higher likelihood of reaching self-sufficiency and functionality (Jones et al., 2014). However, this successful adaptation to symptoms often masks an autism diagnosis and leaves many of these individuals to experience autism-related health issues without understanding the root cause (Griffith et al., 2012).

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Adults who suspect they may have autism often face many challenges in getting an appropriate evaluation and diagnosis. Join us for a discussion of the appropriate tools that should be utilized for an adult evaluation and what to do once a diagnosis has been confirmed. Presented by Claire Schutte, Psy-D, BCBA-D, Staff Psychologist, The Johnson Center for Child Health & Development.

Dr. Gray Atherton discusses the critical role of age and age of diagnosis in shaping the quality of life for autistic individuals. She provides a brief history of autism understanding and considers how changes in diagnostic criteria and cultural stigmas have affected the “lost generation.” The speaker details two studies that emphasize the importance of early intervention and how best to support people who receive a late diagnosis. Atherton explains that diagnosis directly affects quality of life, making detection and diagnosis critical for adults. She notes that further research must incorporate lived experiences and underscores the need for investment in care across the lifespan.

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What Makes the Combined Experience Distinct?

When autism and ADHD co-occur, their interaction can create a complex internal experience that varies considerably between individuals.

Impulsivity associated with ADHD may conflict with the autism-related preference for structure. Sensory overstimulation may intensify emotional dysregulation. Hyperfocus on personal interests may coexist with difficulty completing routine responsibilities.

Executive functioning impairments may be more pronounced when both conditions are present compared to either diagnosis alone (Canals et al., 2024). Some adults may describe feeling caught between competing tendencies such as craving novelty yet needing predictability, seeking connection yet becoming easily overwhelmed. This duality can be difficult to understand without a neurodevelopmental framework.

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Drs. Greg Wallace and Goldie McQuaid share their research on strategies autistic adults develop to compensate for non-social challenges they experience, including sensory sensitivities and executive function differences.

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Greg Wallace, Ph.D., discusses executive functioning and its impacts on lived experiences across the lifespan in autism. He defines executive function (EF) as it relates to cognitive processes, the neuropsychological framework, and real-world outcomes. The presenter provides historical context for EF within autism, highlighting flexibility as the most common EF difficulty for autistic individuals. He outlines recent studies on EF profiles of autistic children, adolescents, and adults, underscoring the connection of EF to quality of life and successful daily living skills across autistic adulthood. Wallace highlights the critical importance of EF in real-world outcomes and notes the severe lack of support beyond early adulthood before the Q&A.

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The Emotional and Mental Health Impact

Undiagnosed neurodevelopmental differences can influence mental health outcomes. A review reported increased rates of anxiety and mood disorders in individuals with co-occurring autism and ADHD. Without explanation, repeated difficulties in work or relationships may be internalised as personal shortcomings. Some adults report long histories of self-criticism before receiving diagnostic clarity.

Recognition does not eliminate challenges, but it may reframe them. Instead of viewing patterns as moral failings or a lack of effort, individuals can understand them as differences in cognitive processing and sensory regulation.

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Two new studies offer insights into the risk for anxiety and depression in students with autism spectrum disorders (ASD) and/ or attention-deficit/hyperactivity disorder (ADHD).

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This article originally appeared in the Autism Research Review International  – Volume 39, No 3

The prevalence of mental health conditions like anxiety, depression, AD/HD, OCD, and suicidality is significantly higher among autistic people than in the non-autistic population. Co-occurring mental issues in autism have been associated with imbalances in the gut microbiome, sensory processing difficulties, chronic inflammation, and autonomic nervous system dysregulation. Our list of resources covers contemporary research on drivers of mental illness and advice for navigating mental health difficulties in autism.

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Hannah Belcher, Ph.D., Autistic researcher, speaker, and author, discusses the often late and missed diagnosis of autistic females. She dives into the gender gap inherent in autism research, assessments, and clinical understanding, demonstrating how this has led to late and misdiagnosis of autism in women. The speaker presents contemporary research working to uncover a female autism phenotype and discusses masking as implicated in mental health and diagnosis. Belcher continually asserts the societal need for greater understanding and accommodation of autistic womens’ lived experiences and outlines what needs to change before the question and answer session.

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Dr. Dena Gassner deconstructs autistic masking and provides a new framework for understanding this universal human experience. She discusses myths about masking being an exclusively autistic experience and asserts the need to move away from the classic binary lens (male vs. female) of autism presentations. The speaker redefines masking as a complex and labor-intensive cognitive process that is especially taxing for autistic people. Gassner highlights the significant risks and harms of persistent masking, including co-occurring conditions and missed or misdiagnosis. She provides a framework for embracing authenticity and conscious adaptation instead of using masking as a default state.

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Work, Relationships, and Daily Life

In professional settings, some adults with ADHD report excelling in creativity, innovation, or deep analytical thinking while struggling with organisation, task prioritisation, or deadline management. In relationships, impulsive communication patterns may combine with difficulty interpreting subtle social cues. Sensory sensitivities may influence social participation.

Emotional regulation challenges are also reported in research. Emotional dysregulation is associated with adult ADHD and may overlap with sensory processing differences documented in autism. Understanding these patterns may guide adaptive coping strategies and reduce interpersonal misunderstandings.

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Researchers in the United Kingdom report that individuals with neurodivergent traits—for instance, those with autism spectrum disorders (ASD) or attention-deficit/ hyperactivity disorder (ADHD)—are at elevated risk for developing chronic fatigue by the time they reach adulthood.

This article originally appeared in the Autism Research Review International  – Volume 38, No 3

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Psychologist Carla Mezefsky, PhD dives into the intricate relationship between emotional  regulation (ER) and autism to highlight current research findings as well as gaps in understanding and treatment applications. She outlines her collaborative research focused on the timeline and physiological parameters associated with ER to provide contemporary intervention and self-regulatory methods.

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Patricia Wright, PhD, MPH, and Katie Curran, MAAP, introduce Proof Positive – The Autism Well-being Alliance. The speakers describe positive psychology, its impact on well-being, and why it matters for autistic people and their communities. Curran details four skills to help with thinking positively and provides suggestions for practicing and applying them to daily life. The speakers emphasize the lack of focus on positive emotions in autism care and how this plays into isolation and mental health issues. They affirm that individuals “can control [their] own well-being” by employing positive psychology and training their minds to build on the things that go well each day. Wright and Curran outline Proof Positive’s free learning and teaching resources before the Q&A.

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Why Recognition in Adulthood Matters

Although early identification is ideal, adult recognition remains valuable.

Accurate diagnosis can:

  • Reduce chronic self-blame
  • Improve workplace communication
  • Inform of appropriate accommodations
  • Guide targeted psychological support
  • Strengthen self-understanding

The DSM-5-TR permits dual diagnosis of autism and ADHD when criteria for both are met, reflecting growing recognition of their co-occurrence. For many adults, receiving an explanation for lifelong experiences provides clarity and validation.

A Growing Shift in Awareness

Public and clinical understanding of adult neurodevelopmental conditions has evolved significantly in recent years. Clinicians acknowledge that many adults were overlooked in childhood, particularly those who did not fit traditional diagnostic stereotypes.

Adult AuDHD represents one example of this broader shift. Recognition fosters insight rather than limitation. It allows strengths such as creativity, pattern recognition, deep focus, and empathy to be understood alongside challenges. Recognising autism and ADHD together in adulthood involves gaining a clearer understanding of how one’s mind works and using that knowledge to support long-term well-being.

The AuDHD Experience

A drawn representation of a person pulling on a rope with traits of autism on one side and traits of ADHD on the other

Art by Dr. Wenn B. Lawson

Author Bio:

Dr. Darren O’Reilly is the neurodivergent founder and CEO of AuDHD PsychiatryHeadshot of Dr. Darren O'Reilly–a UK specialist neurodiversity clinic. The clinic provides private online ADHD, Autism, and combined (AuDHD) assessments for adults and children across the UK. Its multidisciplinary team of psychologists, consultant psychiatrists, prescribers, and ADHD coaches offers compassionate, evidence-based diagnosis, medication, and ongoing support, helping clients gain clarity, confidence, and faster access to care.

Reviewer Bio: 

Professional headshot of a personWenn Lawson, PhD, is an autistic lecturer, psychologist, researcher, advocate, and writer who has shared his professional and personal knowledge for nearly three decades. He has written and contributed to over 20 books and authored many academic papers. He serves on the board of The Autism Research Institute.

Learn more from Dr. Lawson on his YouTube Channel