Adult ADHD | What is Adult ADHD?

What is Adult ADHD?

By David Hennessy, Clinical Psychologist

Cartoon image of David the Psychologist, who is bald and wearing a colourful paisley shirt, sitting in a therapy chair with an open book. A sign beside him lists adult ADHD insights including undiagnosed or subthreshold childhood symptoms, burnout, high allostatic load, long term stress, and nervous system overwhelm. The image includes subtle text reading David the Psychologist @hennessyclinical_psychology.

Adult ADHD insights including similarities to burnout, high allostatic load, long term stress, and nervous system overwhelm. Illustration featuring David the Psychologist.

Adult Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental condition characterised by persistent patterns of inattention, impulsivity, and hyperactivity that interfere significantly with everyday functioning and quality of life. Often misunderstood or overlooked, ADHD can profoundly impact adults and influence relationships, career progress, and emotional wellbeing.

Possibly Undiagnosed or Subthreshold in Childhood

Many adults with ADHD were never diagnosed during childhood or had symptoms that were not pronounced enough to attract clinical attention. Childhood ADHD symptoms may be subtle, resulting in adults who grow up feeling chronically overwhelmed, stressed, or misunderstood without understanding why.

Similarities to Trauma Syndrome and Burnout

The lived experience of adults with undiagnosed or subthreshold ADHD can share similarities with trauma syndromes and burnout. These patterns often include:

Chronic stress: Ongoing efforts to manage ADHD symptoms can contribute to emotional exhaustion and reduced resilience.

High allostatic load: The cumulative effect of stress on the body is often elevated, similar to prolonged trauma or long-term pressure.

Overwhelmed nervous system: Many adults describe a constant sense of overload, mirroring emotional and physiological patterns seen in trauma-related presentations.

Recognising Adult ADHD

Difficulty concentrating or maintaining focus

Persistent procrastination and organisational challenges

Frequent mood shifts and emotional dysregulation

Restlessness or difficulty relaxing

Impulsive behaviours and decisions

Hope and Management

Identifying adult ADHD can be life-changing. Many people describe a deep sense of relief when lifelong challenges start to make sense. With the right support, such as cognitive behavioural therapy, structured lifestyle strategies, and sometimes medication, people often experience meaningful improvements in functioning, emotional balance, and confidence.

References

Barkley, R. A. (1997). Behavioural inhibition, sustained attention, and executive functions. Psychological Bulletin, 121(1), 65 to 94. https://doi.org/10.1037/0033-2909.121.1.65

McEwen, B. S., & Stellar, E. (1993). Stress and the individual. Archives of Internal Medicine, 153(18), 2093 to 2101. https://doi.org/10.1001/archinte.1993.00410180039004

Arnsten, A. F. T. (2009). Stress signalling pathways and prefrontal cortex function. Nature Reviews Neuroscience, 10(6), 410 to 422. https://doi.org/10.1038/nrn2648

van der Kolk, B. (2014). The Body Keeps the Score. Viking.

Faraone, S. V. et al. (2021). ADHD International Consensus Statement. Neuroscience and Biobehavioral Reviews, 128, 789 to 818. https://doi.org/10.1016/j.neubiorev.2021.01.022

Sibley, M. H. et al. (2022). ADHD in adulthood. Current Opinion in Psychiatry, 35(5), 297 to 304. https://doi.org/10.1097/YCO.0000000000000811

Australian ADHD Professionals Association. (2022). Australian Evidence-Based Clinical Practice Guideline for ADHD. https://adhdguidelines.org.au

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