MELBOURNE: On paper, Danielle Harris might be the last person you’d expect to have ADHD. “I was academically capable and well-behaved at school – teachers would never have viewed me as disruptive,” she says.
She went on to launch a successful business career, appearing to thrive in high-pressure situations, regularly staying up until 2am to meet deadlines. “From the outside, I looked productive and driven, but internally my brain was racing constantly, and I was struggling,” says Harris, 52. “At school I’d been constantly under-stimulated and bored.”
Many of us still picture ADHD as the schoolboy bouncing off the walls, or the disorganised adult who forgets their keys and misses important meetings, but there are many other manifestations that are too easily overlooked. “I think women in particular can mask ADHD by overpreparing, overachieving and becoming highly perfectionistic,” says Harris.
The official definition of ADHD focuses on inattention (being distracted, disorganised and forgetful), hyperactivity in body and mind, and impulsivity in both actions and words. Yet experts such as Dr James Kustow, a consultant psychiatrist and author of How to Thrive with Adult ADHD, argue that this risks missing much of what ADHD looks like in everyday life.
“I find it helpful to think of ADHD as a broader, multisystem brain and body dysregulation,” he says. “People don’t come in and say, ‘I am hyperactive’ or ‘I am impulsive’. They come in with the consequences, the way those symptoms play out in their lives.” He believes there needs to be more awareness of “amber lights”, subtle signs that ADHD might be in the mix that are often unexpected and overlooked.
1. Risk-taking in sex and relationships
Whether it is multiple partners, getting bored in relationships or risky behaviours, Kustow says there are higher rates of relationship dysfunction among people with ADHD. “This won’t be the case for everyone, but there can be a ‘chasing what’s shinier around the corner’ mentality, which can strain romantic relationships,” he explains.
Why it happens
Kustow sees this as part of a wider pattern of addictive and novelty-seeking behaviours, driven by a low baseline of the neurotransmitter dopamine in people with ADHD. Dopamine is the “feel-good” chemical and a driving force in the brain’s reward system.
“If the reward system baseline is low, that can lead people to unconsciously seek out ways to boost dopamine, and can lead to addictions of all forms,” he says. “You’re not just talking about risky sexual encounters, but also substances and other addictions such as gambling, pornography, screens, social media, food and work.”
2. Being bendy, clumsy and exhausted
Some people with ADHD are extremely flexible – a condition known as hypermobility, which can lead to sprains and injuries. They may also seem clumsy, bumping into people or things, be accident-prone, or have been diagnosed with dyspraxia, now known as developmental coordination disorder.
Some studies and clinicians have also noted links between ADHD, chronic pain and fatigue, including aching muscles and joints, dizziness, and diagnoses such as fibromyalgia.
Why it happens
“We know that around half of people with ADHD are hypermobile, and what that means is that your connective tissue – the tissue that holds the body together – is lax and more floppy. That can lead to altered proprioception, the sense of where your body is in space,” says Kustow. This can contribute to clumsiness and coordination problems, as well as fatigue and chronic pain.
3. Eating disorders and ‘never feeling full’
Whether it is down to poor planning or emotional and chaotic eating, research shows that people with ADHD are more likely to be obese and to have binge-eating disorder, bulimia and anorexia.
Why it happens
Problems with food are often a result of issues with reward and regulation. “If someone is not organised about meal preparation, they end up hungry and reaching for addictive ultra-processed foods,” says Kustow.
He also points to emerging research into satiety, which is how full people feel. “Many people with ADHD will finish everything on their plate regardless of whether their system needs it or not. This is partly impulse control, partly emotional eating and dopamine craving, but it’s also about a dysregulated sense of satiety – not being able to sense when they are full and no longer hungry,” he says.
4. Workaholism and being almost too organised
Given that a hallmark of ADHD is disorganisation, it can be a surprise when people with ADHD seem almost too organised. For Kieran Jennings, for example, his organisation at work was driven by fear of his boss. “At work, I’d never miss a deadline or forget to call a customer – but this was because I had ‘the fear’ of my boss. At home, however, I was a total nightmare,” he says.
This sort of fear and anxiety can also slip into workaholism and hyperfocus – zoning in so intensely on a project that everyday things like meals and rest fall away.
Why it happens
To Kustow, this behaviour does not conflict with the better-known symptoms of ADHD. “The core symptom here is rejection sensitive dysphoria (RSD). It’s not an official diagnostic term, but we see it often in clinics. People with ADHD are more sensitive to rejection from other people, so this can lead to people-pleasing or perfectionism… They need that stimulus of the anxiety and fear to stay organised, but without it their life is in chaos,” he says.
At the same time, ADHD involves dysregulated attention and reward, so once a task feels urgent or interesting, the person can lock into hyperfocus and be unable to stop. “It’s boom-and-bust productivity, and is exhausting and often hard to sustain,” says Kustow.
5. Insomnia, vivid dreams and sleep apnoea
People with ADHD are often night owls who struggle to shut down their whirring minds to fall asleep. Even when they are sleeping, many say their brains are overactive, and they have vivid dreams and nightmares. They also have much higher rates of sleep apnoea – when breathing repeatedly stops and starts during sleep.
Why it happens
Kustow explains that a shifted sleep-wake cycle – the circadian rhythm – as well as a racing mind can delay sleep. “The circadian rhythm is biologically and physiologically dysregulated. It’s as if someone has taken a normal sleep time and wake time and shifted it about an hour to the right… so people with ADHD as a group get tired later and take longer to fall asleep,” he says.
He also argues that clinicians who see people with sleep apnoea should consider whether ADHD might be in the mix. “Hypermobility affects the tissues around your upper airway, causing it to briefly shut down. That leads to a period of apnoea – not breathing – followed by a gasp. Some studies show that up to a third of people with ADHD have sleep apnoea,” he adds.
6. Hypersensitivity to noise, light and textures
Whether it is lights that are too bright, crowds that are overwhelming or foods that smell too strong, we tend to think of sensory issues as being more linked to autism than ADHD. In fact, many people with ADHD also describe feeling overwhelmed by sensations or, in some other cases, underwhelmed and under-stimulated, leading them to seek out intense sensations because the dial is set too low.
Why it happens
Kustow says many adults with ADHD appear to be either over-responsive or under-responsive to sensory input, even without coexisting autism. He links this to weaker “braking” systems in the brain, which may make it harder to regulate incoming sensations and emotions.
This, he argues, can be a major driver of emotional dysregulation, with overwhelm sometimes leading to shutdown, irritability, fidgeting or stimming (self-stimulatory behaviour such as repetitive physical movements or sounds).
Kustow stresses that none of these things on their own means you definitely have ADHD. “It’s about patterns, not individual symptoms,” he says. “The more of these that are present, the more it increases the likelihood, so then you go and do a thorough assessment.”