10 signs you might have undiagnosed ADHD as an adult – and what to do next
Forgetful, always late, or overwhelmed? These signs could be more than just ‘being busy’.
We all forget things sometimes – the packed lunch left in the fridge, the appointment reminder buried in emails, or the PE kit still by the door. But if you find yourself missing deadlines, running late no matter how hard you try, or feeling constantly overwhelmed by ‘simple’ admin, it might be more than just a busy-mum brain.
According to HealthTest, an online health test platform, around 4% of UK adults live with Attention Deficit Hyperactivity Disorder (ADHD) – but as many as one million could still be undiagnosed. ADHD isn’t just about childhood hyperactivity; in adults, it can show up as forgetfulness, procrastination, or feeling emotions more intensely than others.
Here are 10 common signs that your scattered moments may actually be linked to ADHD
1) You constantly lose things you just had
Keys, phone, purse… gone again? ADHD affects working memory – the brain’s ‘mental sticky note’ – so once you’re distracted, that information can vanish.
2. You procrastinate, even on urgent tasks
Big work deadline? School form that’s due tomorrow? With ADHD, the brain struggles to kick-start boring or overwhelming tasks until the pressure is sky-high.
3. You hyperfocus – then lose all interest
It’s not about lacking focus altogether. Instead, ADHD can mean getting completely absorbed in something exciting… only for motivation to disappear once the novelty fades.
4. You’re late, no matter how hard you try
This isn’t laziness – it’s something experts call ‘time blindness’. You underestimate how long things take, or get caught up in another task, and suddenly you’re late again.
5. You zone out in conversations
Find your mind drifting mid-meeting or halfway through a chat with your child’s teacher? ADHD brains struggle to filter distractions, especially in low-stimulation settings.
6. You start projects – and don’t finish them
The buzz of starting something new gives a dopamine hit. But when things get repetitive, ADHD brains find it much harder to stick with them.
7. Your emotions feel ‘louder’ than others’
Small frustrations can tip you into overwhelm, while little wins feel euphoric. ADHD affects emotional regulation, meaning reactions rise faster – and last longer.
8. You forget appointments despite reminders
Even with alarms set, ADHD can disrupt ‘prospective memory’ – remembering to act at the right moment. So the reminder pings, but you’re too deep in something else to follow through.
9. Everyday admin feels like climbing a mountain
Bills, school emails, tax returns – tasks that are low in stimulation but high in importance often feel especially exhausting to face.
10. You’ve been called ‘lazy’ or ‘disorganised’
Many adults with ADHD grew up labelled this way. In reality, their brains are simply wired to process information, regulate focus and manage time differently.
The hidden toll of undiagnosed ADHD
Missing deadlines or losing your keys isn’t just frustrating – it can ripple out into other parts of your life including:
Relationships: Forgetting plans or reacting strongly in arguments can upset and hurt others.
Finances: Impulsive spending and avoiding admin can cause late fees and spiral into debt.
Career: Tardiness and unfinished work may hold back promotions.
Mental health: Constantly feeling behind or criticised can feed anxiety, low self-esteem and burnout.
What to do if these signs feel familiar
If you recognise yourself in all or some of these 10 signs, the good news is there are steps you can take:
Try an online screening test: You can find adult ADHD test online on websites like HealthTest or ADHD UK that can give you a first sense of whether further assessment might help.
Speak to your GP: Ask about a referral for an ADHD assessment – but be aware NHS waits can be over 12 months.
Consider private diagnosis: Many adults choose this route to avoid delays, then share results with their GP.
Make small changes now: Break big tasks into steps, use visible reminders, and build in buffer time to help with lateness and overwhelm.
Living with ADHD doesn’t have to mean living in chaos. With support, strategies and understanding, it’s possible to find balance – and to stop blaming yourself for things your brain was never wired to do in the first place.
Small changes that make a big difference with ADHD
Here are 5 practical hacks you can try today if you think you may have undiagnosed adult ADHD:
Break it down – split big jobs into smaller steps and tick them off as you go.
Go visual – use sticky notes, wall planners or colour coding to keep tasks front of mind.
Add buffer time – build in an extra 10–15 minutes when leaving the house or heading to appointments.
Pair tasks with rewards – listen to a podcast while folding laundry or make a favourite coffee before opening emails.
Set one ‘non-negotiable’ – choose just one priority task for the day, so it feels achievable instead of overwhelming.
These won’t replace professional help, but they can ease daily stress while you explore assessment or treatment options.