Steve Ollington

The Lesser Known ‘Quirks’ of ADHD

Most people with a basic understanding of ADHD will recognise the core behaviours associated with it, of being often and easily distracted, impulsive with speech and action, and possibly (though not always outwardly) hyperactive or restless.

Posts on social media imply many other behavioural connections to ADHD, some accurate, some not. Some of the experiences are just standard, nothing to do with being ADHD and no more common than within the rest of the population. Some may well have an increased likelihood in people with ADHD, but also have a similarly increased likelihood in people with many other conditions such as anxiety – and so are not by themselves ‘signs’ of ADHD.

However, there are behaviours and experiences that are ‘more likely’ to occur in people with ADHD, some of which could be taken as confirming factors to some extent. As such they should not be counted as anything other than quirks, unless they accompany the core symptoms of inattention, impulsivity, and possibly hyperactivity at the persistence and severity required for ADHD diagnosis.

Before discussing these phenomena, it’s important to understand what is meant by the phrase ‘more likely’.

What is meant by ‘more likely’?

If someone is ‘more likely’ to experience something when they are ADHD, it doesn’t mean that all ADHD people will experience it – or that people who are not ADHD won’t experience it. Here is an example.

A common ADHD trait is defiance, to the level of also being diagnosed with Oppositional Defiance Disorder (ODD)

Around 4% of Non-ADHD children show levels of defiance meeting diagnostic criteria for ODD (1)

ADHD More Likely 1

Around 40% of ADHD children show levels of defiance meeting diagnostic criteria for ODD (2)

So, ADHD children are TEN TIMES more likely to also be ODD than non-ADHD children

Yet, fewer than HALF of children with ADHD would recognise ODD in themselves.

So that’s what ‘more likely’ means in this context. Anything shown in the list below has a higher likelihood of showing up in someone who is ADHD than someone who isn’t, but that doesn’t mean it will, and it doesn’t mean people without ADHD won’t also experience the same things (albeit with a lesser chance). That’s why we shouldn’t use these signs as a diagnostic tool.

(1) Aggarwal, et al., 2022 *, (2) Higuera, 2019 – *The number of ODD children is estimated between 2 and 11%, which includes ADHD children, who are more likely to be ODD. Removing the ADHD children from that figure provides an estimate of 4%

What else is ‘more likely’ for people with ADHD?

As discussed, we know there are the core traits, with common issues around inattention, impulsivity, and hyperactivity – and there are other well known challenges with working memory, co-morbidities such as anxiety, depression, and much else. We also know that people who are ADHD are more likely to have a lower life expectancy, face school expulsion, incarceration, addiction issues, and many other life challenges – but there’s already a lot of content around these factors. This article will instead list some of the lesser known behaviours and experiences that are also ‘more likely’ with ADHD…

Food issues: People with ADHD are more likely to exhibit picky eating habits, characterised by aversions to certain tastes, textures, or even the appearance or names of food. Food texture issues are likely the most commonly experienced, with others often not understanding how off-putting certain textures can be. With some relevance, it’s also fairly commonplace for people with ADHD to sometimes eat while standing, even if others are sat around the dinner table – this is likely because they have ‘the next thing’ on their minds, rather than the meal they are consuming. The taste and texture, etc… manifestation is technically referred to as Avoidant/Restrictive Food Intake Disorder (ARFID), with studies showing associations between core ADHD symptoms and eating patterns, and links to ADHD traits and sensory sensitivities.

(Bayoumi, S.C., et al, 2025; Kambanis, P.E., et al, 2020; Thomas, K.S., et al, 2025; Kaisari, P., et al, 2018; Ptacek, R., et al, 2014)

Sugar addiction: People with ADHD are more prone to craving sugar because of the dopamine hit it provides, which makes sense when you consider that they have lower dopamine levels. Sugar can be addictive to anyone, but it’s especially luring to people with ADHD. This often leads to adults consuming sweets and chocolate in volumes more typically seen in children, a habit that can be particularly unhealthy when such foods replace proper meals, resulting in tiredness from insulin spikes, commonly known as “sugar crashes”. High sugar diets can cause a lot of problems, and whilst they of course do not ’cause’ ADHD, they can exacerbate the more troublesome of traits with it.

(Ollington, S., 2024a)

Tight muscles (Mild Hypertonia): People with ADHD are more likely to experience high muscle tension, which results in stiffness and a lack of flexibility, a condition technically termed Mild Hypertonia. Research indicates correlations between chronic pain, muscle tension, and ADHD, as well as connections between motor regulation problems and pain in adults diagnosed with ADHD. Whilst all people can get tight muscles and lose their flexibility with age and reduced activity, people with ADHD should make extra efforts (e.g. regular Yoga, Pilates, stretching exercises) in order to keep their mobility.

(Brennecke, U., 2024; Stray, L. L., et al, 2013).

Poor posture, and postural sway: ADHD people are more likely to exhibit poor posture, in particular what’s known as the ‘head-forward posture’, and increased postural sway, which refers to the body’s continuous, small, and involuntary movements used to maintain balance when standing upright. These postural issues are also related to the prior mentioned muscle tightness, increasing the need for stretching to address the imbalance, stiffness, and the many physical pain and other health challenges that can eventually stem from poor posture.

(Jansen, I., et al, 2019; Pedersen, T., 2022; NeuroLaunch.com, 2024).

Sitting in funny positions: It is a commonly observed behaviour for people with ADHD to sit in unconventional positions. Examples of this being is having their legs up on chairs, sitting on their heels (more common when young), and sitting low down in chairs, bending at the upper back with the legs out straight – this is connected to the postural issues, so it’s important for people to be mindful of it, especially over long periods.

(Roberts, 2024).

Late nights, groggy mornings, poor sleep: Sleep issues are common for those with ADHD, manifesting as late nights, difficult mornings, and overall poor sleep quality, often due to rumination, delayed sleep onset, and a late chronotype. Insomnia in people with ADHD is sometimes more accurately described as “Restless Brain Syndrome,” where the brain becomes overactive to compensate for a lack of sensory input, or ruminating on anything from problems to ideas. These sleep disturbances are also intertwined with circadian rhythm dysregulation (the internal body clocks, which are often not aligned others, making them more likely to have greater energy in the evenings or night times than the mornings). Unsurprisingly, the result of this is morning ‘grogginess’ and tiredness throughout the day. The best (and only, really) way to go about resolving this is trying to be as disciplined as possible with bed times at a reasonable hour, and then hoping to be able to fall asleep.

(Bailey, 2018; Pacheco, 2025; Ollington, S., 2025a).

Time blindness: People with ADHD are prone to experiencing “time blindness,” which is a cognitive difficulty in accurately perceiving and managing the passage of time, leading to challenges with present versus future planning and understanding temporal concepts. It’s also known as the Now vs Not Now Phenomenon, and is why people with ADHD will often leave things until the last minute, or regularly be late. This is not always the case though, many people with ADHD will have developed coping strategies around this, learned behaviour from when they used to get into trouble for it when younger, or due to missing out on things from lateness, etc…

(Ollington, S., 2024b).

Seemingly having hearing challenges: It’s not uncommon that people with ADHD will think they have poor hearing, while others around them may tell them so. But it’s not necessarily hearing that’s creating the problems, it’s processing what they’ve heard. APD (Auditory Processing Disorder) is significantly more likely to occur with ADHD. There are different ways in which it manifests, from delayed processing of what has been heard, or missing elements of the sounds (often words) due to both external and internal distractions (e.g. background noise, thoughts or emotions).

(Ollington, S., 2024c).

Delay aversion: People with ADHD often experience “delay aversion”. This is more complex than simply impatience, though there’s plenty of overlap. Some of it comes from past negative experiences, where they will be driven by fear of forgetting if they don’t do it right away. Some of it comes down to fear of overwhelm if they let the to-do list build up, or worry that things may take a lot longer than they will. Some, from that internal restlessness and a need to just get things done, so it can be checked off the list allowing them to move onto the next thing. It’s also related to a need for validation, that comes only from outcomes (due to trouble with processes). But also, it’s a pattern of choice maintained partly by negative reinforcement – meaning a preference for immediate rewards is reinforced because that allows for escaping the negative affect experienced while waiting for a delayed reward option. That is to say, waiting is almost excruciating – so powering through as much and as hard as possible is an attempt to reduce waiting. Waiting on others however, is often beyond their control, and so they must suffer it.

(Antrop, I., et al, 2006; Sonuga-Barke, E.J.S., et al, 1992; Chronaki, G., et al, 2019).

Boredom intolerance: Otherwise known as “understimulation,” boredom intolerance is a characteristic where individuals with ADHD have a low threshold for monotony and seek out novelty and engagement to maintain attention and avoid feelings of restlessness. Recent findings support the “Cognitive Theory of Boredom”, suggesting that ADHD people experience boredom due to difficulties sustaining attention and using working memory effectively… People with ADHD are very interest-based, meaning if they’re interested then they can focus and excel, but if they’re not interested (and they can’t force interest) then they will be more easily bored and find it all the more difficult to concentrate. However – whilst boredom leads to mind wandering, that mind wandering can lead to creativity. So with the knowledge of a problem, and then becoming bored by the details, ADHD people’s minds can wander off into problem-solving for that task at hand.

(Orban, S. A., et al., 2025; Hsu Chia-Fen, et al., 2025; Koseva, N., 2024; Bench, S. W., & Lench, H. C., 2013).

Stimming: Stimming refers to repetitive physical or vocal behaviours such as rocking, fidgeting, tapping hands or feet, squirming while seated, chewing pens, sleeves, or nails, and much else. Whilst other conditions are often what people will relate to stimming, people with ADHD may engage in these actions too – normally not consciously, but sometimes as an intentional coping strategy. Stimming can help them to focus and regulate sensory input – sort of allowing, or channelling distraction of the subconscious into something so that it won’t distract what the conscious mind is trying to do. This happens a lot more when younger, or at least becomes more subtle with age.

(Son, H. M., et al., 2024; Hartanto, T. A., et al., 2016).

Tics: People with ADHD have an increased likelihood of experiencing tics. This is not the same as stimming – Tics are sudden, repetitive, non-rhythmic movements (or vocalisations). Some examples being increased blinking or twitching, or sudden compulsive movements such as tilts of the head, lifting of a shoulder, and more. There’s a connection here with some OCD (Obsessive Compulsive Disorder) where instead of involuntary movements, it’s semi-voluntary – meaning the person is compelled to make the movements. It’s conscious in this case, and can be supressed, but not easily, and often not for long. Either way, levels of tiredness, stress, and much else can be a factor in how much this will occur.

(Groen, Y., et al., 2017; NHS, 2017; ADDA., 2023).

Vocal stimming and vocal tics: As a form of stimming, vocal stimming involves repetitive sounds or words and is more likely to be observed in people with ADHD (along with other conditions). It serves as a self-regulatory mechanism, and/or is a way of dealing with emotions or anxious feelings. This too, will likely take place more when tired, or under some kind of pressure or nervousness. Sometimes it’s when there’s too much going on in the mind, that the person is trying to communicate out. It’s not just noises, either – for example, it can be constant short, sharp exhales of breath, as if trying to empty the lungs, or throat clearing, little ‘fake coughs’.

(Gillette, H., 2024; Masters, T., 2024).

Dehydration: People with ADHD are prone to dehydration because they may forget to drink water as regularly as they should. This is because they fail to notice their body’s internal signals of thirst, indicating a challenge with ‘interoception’ – which gets described as the body’s ‘8th sense’. It’s basically bodily awareness, and is the sense that allows us to interpret signals from our internal organs about physical and emotional states. This happens a lot when ADHD people are too hyperfocused on other things over long periods, in which they can forget to eat or drink… or when younger, attend the bathroom (although that happens a lot with most children, too).

(Neff, M., 2023; Manion, K., 2023).

Justice Sensitivity: ADHD people are more likely to experience what is known as “justice sensitivity,”. This usually manifests a bit differently with age. In younger years, it will be a quick temper – but as that mostly becomes under better control with maturation and learning, what remains is still the trigger of it – a strong sense of outrage at perceived unfairness. Note the word ‘perceived’ in that – it doesn’t always mean the judgment of unfairness is being made correctly. It can be described as a heightened emotional response to ‘perceived’ injustices, which will be felt deeply, often resulting in the person then ruminating and obsessing over the issue, which then drives them to act… sometimes in extreme ways. This can be a good or bad thing, depending on the circumstances. It can be a driver of positive change, choice in career, defending one’s self or other, and generally a desire to help. But it can also get people into a lot of trouble, cause problems at school or work by pushing back too much, or escalate into violent situations. It often comes down to a refusal to back down, with the person feeling they have right on their side, where they will go much further than they perhaps should in order to ‘restore the balance’, even if it costs them. This is particularly problematic when they may have jumped to conclusions, or are simply in the wrong but can’t see it. The prison systems are over-represented with ADHD people, and at least some of the reason for that may be from some of them taking things too far.

(Ollington, S., 2025b; Ollington, S., 2024e).

An “overclocked internal monologue”: This doesn’t belong in this list really, because it’s not just ‘more likely’, it’s a definite characteristic for people with ADHD. This is essentially about ‘talking to yourself’ in your head, but incessantly. Their minds are perpetually racing, with constant, always-on spontaneous thoughts. This includes “unfocused exploration episodes,” that are more numerous, form smaller clusters, and demonstrate ‘greater semantic exploration’ compared to neurotypical peers. This unsurprisingly feeds into making it difficult to fall asleep!

(Kérébel, A., et al, 2024; Martz, E., et al., 2023).

People pleasing: The behaviour of “people pleasing” is common in people with ADHD, and is understood as a component of RSD (“Rejection Sensitivity Dysphoria”), which is where there is an intense emotional pain response to perceived or actual criticism, rejection, or teasing (which can created problems with that ‘perceived’ aspect of the justice sensitivity discussed above). Whilst RSD will often cause people to become defensive, it also factors into learned behaviours. Growing up experiencing RSD, and feeling so easily hurt or betrayed by sometimes even the smallest of slights, leads to coping mechanisms of wanting to avoid not just confrontation but even minor disagreement. As a result, in order to avoid the effects of RSD, they will try their hardest to make and keep everyone happy with them. But it’s not just about RSD. People with ADHD are often fully aware of areas they find challenging – especially in the workplace, where they know that things such as their working memory issues may be held against them by some, so they subconsciously attempt to offset this by trying their hardest to please others, in the hope that any judgment against them will then come less harshly. They are unknowingly trying to make up for their perceived ‘deficits’. It’s related to masking, and is exhausting.

(Dodson, W., 2017; Ramsay, R., 2023; Cohen, D., 2025).

Naivety: People with ADHD can exhibit a degree of naivety, partly because they tend to project their own ideals and values onto others. It sometimes gets described as a ‘child-like quality’ and has been said that many with ADHD ‘see the world as it should be, rather than as it is’. This connects into both the justice sensitivity and the RSD. People with ADHD often find themselves struggling to meet societal expectations in a variety of ways, but so too does society (and by that is meant, other people) often fail to meet the expectations of people with ADHD. If the person with ADHD cares about others they know, they will project that and assume that to be reciprocal. Reality is different though, and so these people will often find themselves having been too trusting of others, too loyal, and much else. This naivety is often overt, and displayed in many ways – and that may lead to them being undermined and underestimated in social interactions or in some workplaces, where it’s ‘just business’.

(Ollington, S., 2024d).

Trouble with throwing or catching a ball/frisbee, etc.: People with ADHD are ‘more likely’ to experience difficulties with fundamental motor skills, such as throwing or catching a ball or frisbee. This is attributed to challenges with force control and timing, and may overlap with developmental coordination disorder. It reflects broader motor impairments and differences in motor cortex inhibition. However, there are many ADHD athletes out there, who excel in sports requiring these skills – demonstrating that ‘more likely’ doesn’t mean everyone, or even a majority. It just means that it’s more commonly experienced by people with ADHD. For example, despite all those brilliant ADHD athletes who can throw and catch balls very well, the image below is something that resonates with me throughout my life as someone with ADHD, just as I know it does with plenty of others.

(Ament, K., et al., 2015; Chen, Y.-Y., et al., 2011; Pitcher, T. M., et al., 2002; Meachon, E.J., et al., 2025; Gilbert, D. L., et al., 2011; Fliers, E., et al., 2008).

Credit to Ana Krajinovic for the image - throwing or catching a ball with ADHD
Credit to Ana Krajinovic for the image, found originally at https://medium.com/anas-stories/cant-catch-a-ball-adhd-confessions-in-comics-469ec0db3039

References