ADHD Explained
/ADHD is a neurodevelopmental condition characterised by inattention, hyperactivity, and impulsivity. There are three subtypes of ADHD: Hyperactive, Inattentive and Combined. According to MRI scans taken in 2017 by Gehricke JG et al, the brains of children with ADHD showed smaller brain volumes with the size of specific brain structures reduced. By adulthood, the ADHD brain has mostly normalised in size but not in function. The ‘ADHD brain’ is literally wired differently with complex micro and macrostructures showing smaller amounts of white and grey matter contributing to poor executive function, emotion regulation and attention. Anxiety and depression can be comorbid with ADHD as can Obsessive Compulsive Disorder and Oppositional Defiant Disorder. People with ADHD often experience learning difficulties. The following explains more about the role of specific brain structures and regions and how they differ in ADHD.
Grey and white matter house nerve bodies and axons respectively, signalling across a synapse (a gap between the two). In ADHD there is a delay in signalling, contributing to slower processing.
The Prefrontal Cortex regulates behaviour, emotions and attention. People with ADHD tend towards hyperactivity, inattention and poor decision making do to alterations in circuitry and weaker activation of the Prefrontal Cortex.
The Basal Ganglia responsible for motor learning, also helps regulate behaviour, emotions, and the ability to plan, focus, and multi-task; all of which are dysregulated with ADHD due to inward deformations in the Basal Ganglia resulting in dopamine dysregulation.
The Default Mode Network (DMN) is active when we are at rest enabling daydreaming. In an ADHD brain, the DMN has difficulty switching off. Where normally it would relay messages to the Prefrontal Cortex to switch tasks, in ADHD the process is slower and therefore we can get stuck daydreaming or in mental wandering.
The Limbic System is a set of brain structures including the hippocampus, hypothalamus, amygdala:
The hippocampus is responsible for memory formation and spatial navigation; your ability to know where you are, where you want to go and how you plan to get there. People with ADHD suffer from poor working memory and a poor sense of direction.
The hypothalamus controls the autonomic nervous system and hormone release. People with ADHD can be stuck in sympathetic dominance (fight-flight mode) as the stress hormones cortisol and norepinephrine are dysregulated. They therefore have difficulty managing stress as the Hypothalamic-Pituitary-Adrenal (HPA) axis, responsible for the stress response is dysfunctional. Cortisol is also related to our circadian rhythm which is dysregulated in ADHD causing difficulty getting to sleep and waking up.
The amygdala is the brain’s emotional alarm system. In ADHD it suffers altered connectivity with the prefrontal cortex, the result of which is an overactive amygdala which explains the difficulty in emotional regulation, rejection sensitivity dysphoria and impulsivity.
The thalamus relays sensory signals to the cortex. It can be reduced in volume in people with ADHD causing inattention and difficulty switching tasks, hence our ability to occasionally hyper-focus but comorbid with emotional dysregulation; if you try to drag someone away from a task on which they are hyper focused, they can have an emotional outburst.
It is suggested that as well as genetic mutations caused by certain syndromes, environmental factors like chronic stress during brain development could contribute to underdeveloped brains. Today, more and more research is being done into how Yoga and mindfulness techniques can regulate the autonomic nervous system, support the HPA axis and positively affect specific brain structures and regions. It can be a practical adjunct in the treatment of ADHD.
If you suspect you have ADHD, speaking to other people with the condition can help. There are a number of interesting and validating podcasts I recommend, including ADHD Chatter Podcast on YouTube or Spotify and https://www.adhdwomenswellbeing.co.uk/adhd-podcast
If you want a diagnosis, consult your GP. You can either go on a very long waiting list, or go down the Right to Choose path which can speed things up. Alternatively, you could arrange a private assessment in your area.
The following article may be helpful: https://magazine.medlineplus.gov/article/adhd-across-the-lifespan-what-it-looks-like-in-adults
Why not read A Day in the Life of a Woman with ADHD.
References:
Vogt BA. Cingulate impairments in ADHD: Comorbidities, connections, and treatment. Handb Clin Neurol. 2019;166:297-314. doi: 10.1016/B978-0-444-64196-0.00016-9. PMID: 31731917.
Gehricke JG, Kruggel F, Thampipop T, Alejo SD, Tatos E, Fallon J, Muftuler LT. The brain anatomy of attention-deficit/hyperactivity disorder in young adults - a magnetic resonance imaging study. PLoS One. 2017 Apr 13;12(4):e0175433. doi: 10.1371/journal.pone.0175433. PMID: 28406942; PMCID: PMC5391018.
Gonzalez NA, Sakhamuri N, Athiyaman S, Randhi B, Gutlapalli SD, Pu J, Zaidi MF, Patel M, Atluri LM, Arcia Franchini AP. A Systematic Review of Yoga and Meditation for Attention-Deficit/Hyperactivity Disorder in Children. Cureus. 2023 Mar 14;15(3):e36143. doi: 10.7759/cureus.36143. PMID: 37065343; PMCID: PMC10101238.
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Sobel LJ, Bansal R, Maia TV, Sanchez J, Mazzone L, Durkin K, Liu J, Hao X, Ivanov I, Miller A, Greenhill LL, Peterson BS. Basal ganglia surface morphology and the effects of stimulant medications in youth with attention deficit hyperactivity disorder. Am J Psychiatry. 2010 Aug;167(8):977-86. doi: 10.1176/appi.ajp.2010.09091259. Epub 2010 Jul 1. PMID: 20595414; PMCID: PMC4254769.
Luu B and Fabiano N (2025) ADHD as a circadian rhythm disorder: evidence and implications for chronotherapy. Front. Psychiatry 16:1697900. doi: 10.3389/fpsyt.2025.1697900
Onnink AM, Zwiers MP, Hoogman M, Mostert JC, Dammers J, Kan CC, Vasquez AA, Schene AH, Buitelaar J, Franke B. Deviant white matter structure in adults with attention-deficit/hyperactivity disorder points to aberrant myelination and affects neuropsychological performance. Prog Neuropsychopharmacol Biol Psychiatry. 2015 Dec 3;63:14-22. doi: 10.1016/j.pnpbp.2015.04.008. Epub 2015 May 5. PMID: 25956761; PMCID: PMC4515357.
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(https://www.sciencedirect.com/science/article/pii/S2213158216300468)https://www.davidsongifted.org/gifted-blog/understanding-diagnosing-and-coping-with-slow-processing-speed/
https://chadd.org/attention-article/managing-inattentive-adhd-with-psychosocial-treatments/
https://chadd.org/attention-article/mindfulness-meditation-and-yoga-as-treatments-for-adhd/
https://my.clevelandclinic.org/health/body/limbic-system












