Must pay better attention: The Dopamine Deficit Argument

By Dr Rachel V. Gow, PhD, RNutr, FHEAChild Neuropsychologist, Nutritional Neuroscientist and Founder of Nutritious Minds Trust Charity

The Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) has arguably reduced ADHD to a somewhat simplistic account of inattentiveness (distractibility/disorganisation), hyperactivity and impulsive behaviour. Pharmacological funded research carried out by psychiatrists and researchers has long focused on the somewhat outdated and too simplistic “dopamine deficit” model of ADHD, which has been the foundation of prescription medications for decades. Current science now acknowledges that ADHD is a complex system involving a dysregulation of systems and that the dopamine deficit model is too simple and inefficient an explanation.

Although, it is important to note that medication continues to play an important role in reducing ADHD symptoms in many people. The dopamine deficit hypothesis is just one theory and like many theories needs to be empirically tested. Measuring dopamine in humans however is just not possible. The reality is that seldom anyone diagnosed with ADHD will undergo an advanced neuroimaging and specialised procedure such as PET (Positron Emission Tomography) which involves ingesting a radioactive tracer such as (11C) raclopride which binds to dopamine receptors and enables researchers to map receptor availability and activity (MacDonald et al., 2024).

This procedure can be used in research, although it is extremely time-consuming and costly (this type of scan would cost between £1200-£2500+ in the UK), so it seldom occurs outside of clinical research.

Heterogeneity of ADHD

ADHD is a heterogeneity condition. What that means is problem, no two people experience ADHD in the exact same way, as it varies widely in its symptoms, causes, brain differences, and responses to treatment.

This results in a disparity between symptoms among individuals with ADHD, and it must be recognised that this is not a single, uniform condition.

What your ADHD symptoms look like, is not necessarily going to be what another person experiences. Clinical profiles and diagnoses differ, symptoms can change over time, they can worsen or get better, and someone can also present with mostly hyperactive-impulsive symptoms, or mostly inattention and emotional regulation symptoms can also vary substantially (Luo et al., 2019).

The heterogeneity in ADHD is thought to be influenced by both genetic variants, and environmental risk factors preconception and perinatally (Bonvicini et al., 2018; Uchida et al., 2018).

Currently, a diagnosis is determined by a clinician guided by the DSM-5 presentations of ADHD in children which ranges from: (1) predominantly inattentive, (2) predominantly hyperactive/impulsive and (3) the combined presentation. The number of symptoms, the severity of symptoms and whether the behaviours occur both at home and at school is diagnostically relevant.

Symptoms are not evaluated in relation to biological markers, brain scans, physical symptoms (e.g.,  Postural Orthostatic Tachycardia Syndrome (POTS), Ehlers-Danlos Syndrome (EDS), celiac disease or nutrient insufficiencies.

However, practitioners that adopt a holistic approach feel that this is arguably the missing piece and many researchers in the field of nutritional psychiatry advocate the nutrition must be mainstream in medicine (Sarris et al., 2015). Essentially, that we need to put the biology back into psychiatry.

Lived experiences are also broad. Neurodivergent symptoms may involve difficulty regulating attention rather than an absence of attention; intense hyperfocus on one task yet intense procrastination around another; time blindness, restlessness, sleep disruption, impulsive eating, emotional volatility, rejection sensitivity and exhaustion after prolonged self-control.

Emotional regulation in ADHD has arguably not been given the research investment it warrants. As a mother, personally, it was incredibly challenging to see my son struggle with his emotions, from being easily excited to sullen, and occasionally, unprovoked explosive outbursts. New research suggests that one in two children with ADHD experience emotional dysregulation (Hou et al., 2024).

It is, however, important to be clear. Biological regulation which includes emotional stability, is not regulated by the brain in isolation. It depends upon physiological homeostasis (meaning the body's ability to keep its internal environment stable and balanced even if the environment changes) in interconnected, distributed networks. These networks are in turn influenced by sleep, energy availability, nutritional status, immune signalling, hormonal state, autonomic balance and the wider environment.

Therefore, a tired, hungry, inflamed, anxious, depressed or physically unwell nervous system cannot be expected to function in precisely the same way as one that is rested, nourished and supported (Peçanha et al., 2025).

Diagnosis: An Explanation for Everything?

A neurodevelopmental diagnosis can bring an enormous sense of relief, insight and a feeling of almost liberation. It can provide context for lifelong difficulties, reduce any lingering shame and open the door to support.

However, once ADHD or autism appears in a medical record, there is a risk that every current and future symptom, habit or personality trait is attributed to it. Social media is awash with influencers stating that bumping into kitchen cupboard doors to liking certain colours is “my ADHD”.  Although, ADHD is increasingly becoming a social identity, it is important to acknowledge that it is a psychiatric descriptive label created by the American Psychiatric Association (APA) and its respective diagnostic manual – the DSM-5, to diagnose a certain cluster of behaviours (Stern & Lamash, 2025). The official term appeared in 1987, built on several earlier descriptions and terms including “Minimal Brain Dysfunction” and “Hyperkinetic Reaction” (Gow et al., 2021). For a detailed overview of the evolution of ADHD from Sir Alexander Crichton in 1798, to the present day, please read, Chapter 1 of my book, Smart Foods for ADHD and Brain Health (Gow et al., 2021).

Attributing everyday behaviours to ADHD, is known as diagnostic overshadowing or ADHD essentialism. This phenomenon describes an over-identification when individuals begin to frame any behaviour, action, flaws or habits as due to their ADHD. A loss of agency occurs, which can hurt growth or slow progress as ADHD becomes the default explanation for everything. 

Professional support can be effective to help the individual to explore techniques to separate personal habits from ADHD symptoms, and prevent slipping into a series of identity distress, defence mechanisms or learned self-helplessness, where everything is processed through the lens of ADHD and neurodivergence (Hall et al., 2026). 

Adjusting to a new diagnosis takes time, and identifying as neurodivergent or neurospicy often feels different to actually receiving a confirmed label. Take time to process this new information. Mixed feelings are completely natural; some people cry and genuinely feel sad. Others feel immediately reassured, while others feel a little fearful, especially about sharing this new information with others. I suggest to give yourself time to settle and adjust to the diagnosis, speak to close friends and family, share in a safe community space such as one of our Nutritious Minds Support groups, when you feel ready, perhaps venture our into neurodivergent friendly online or in-person groups. Remember above all to be kind to yourself; you are not alone, and we are here to support you.