ADHD (attention deficit hyperactivity disorder) in adults is a condition where the brain works differently to most people, affecting attention, energy levels and impulse control (NHS). In adults it usually shows up as forgetfulness, disorganisation, restlessness and acting on impulse, starting in childhood and still causing real problems at work, at home or in relationships (NICE NG87).
Key takeaways
- ADHD symptoms fall into two groups: inattentiveness, and hyperactivity and impulsiveness. Most people have some of both (NHS).
- For a diagnosis, symptoms need to have started in childhood, show up in two or more settings, and cause at least moderate difficulty (NICE NG87).
- In a 2023/24 survey in England, 13.9% of adults screened positive for ADHD traits, but only 1.8% said they had been diagnosed by a professional (NHS England Digital). Screening positive is not a diagnosis.
- Only a specialist can diagnose ADHD. For most people, a GP is the first step (NICE NG87).
What is ADHD in adults?
ADHD isn't a character flaw or a lack of effort. The cause isn't always known, but it often runs in families and may be linked to genetic differences (NHS).
It's often thought of as a childhood condition, but NICE is clear that ADHD may persist into adult life (NICE NG87). NHS England estimates that around 2.5 million people in England have ADHD, including people who have never been diagnosed (NHS England Digital, February 2026).
Many adults only start to wonder about ADHD later in life. That's especially true for women, whose symptoms are more often the quieter, inattentive kind (NHS). Our guide to ADHD in women explains why it's so often missed.
Signs of ADHD in adults
The NHS lists these as the main symptoms in adults (NHS):
| Symptom group | Signs listed by the NHS | How it can look day to day |
|---|---|---|
| Inattentiveness | Easily distracted or forgetful | Drifting off in conversations; forgetting appointments |
| Finding it hard to organise your time | Running late; deadlines creeping up unnoticed | |
| Finding it hard to follow instructions or finish tasks | A trail of half-finished jobs and projects | |
| Losing things often, like your wallet, mobile or keys | Daily hunts for the same few things | |
| Hyperactivity and impulsiveness | Having a lot of energy or feeling restless | Finding it hard to sit through meetings or films |
| Being very talkative or interrupting | Finishing other people's sentences | |
| Making quick decisions without thinking about what might happen | Snap choices you later regret |
Everyone has days like this. What matters is how often it happens, how long it has been going on, and how much it gets in the way.
ADHD symptoms in adults vs children
The core traits are the same, but they can look different with age. In children, hyperactivity may mean running about or climbing where it isn't appropriate. In adults it's more often an inner sense of restlessness (Open University; NHS).
The diagnostic criteria reflect this. Under DSM-5, people aged 17 and over need at least five symptoms from a list, rather than six for younger children. Some symptoms must have been present before age 12, and in two or more settings, such as home and work (Open University).
Symptoms can seem to "appear" when life gets busier, but often the traits were there all along. If your symptoms mainly involve focus and organisation, our guide to inattentive ADHD may help.
What else could it be?
ADHD rarely travels alone. People with ADHD often have other conditions too, such as depression, anxiety, addictions or a learning difficulty like dyslexia (NHS).
Other things can also cause poor concentration and forgetfulness, including stress, low mood and poor sleep. That's why NICE says adults should be referred for an ADHD assessment when their symptoms began in childhood, have persisted, and aren't explained by another mental health diagnosis (NICE NG87). For women in midlife, it's worth reading our guide to ADHD and menopause, as the symptoms can overlap.
How adults get assessed in the UK
If ADHD symptoms are affecting your studies, work or relationships, the NHS advises speaking to a GP, who can refer you to an ADHD specialist (NHS). A diagnosis should only be made by a specialist psychiatrist or another appropriately qualified professional with expertise in ADHD (NICE NG87).
The assessment looks at your symptoms now and in childhood, and how they affect work, education, family life and health (NHS). Want to organise your thoughts first? Try our ADHD self-screener. It's a starting point for a conversation, not a diagnosis. Our full guide covers how to get an adult ADHD assessment in the UK, including the NHS route and Right to Choose.
If ADHD is diagnosed, support can include lifestyle changes, workplace adjustments, talking therapies and medication (NHS). Treatment options, including medicines, are discussed with your clinician, along with their benefits, risks and alternatives.
Renvo can help. Our ADHD service starts with a free initial consultation to talk through your experiences and next steps. That first conversation is not itself an assessment or a diagnosis. adult ADHD assessment
When to see a GP
Speak to a GP if you think you might have ADHD and it's affecting your work, studies or relationships (NHS). ADHD itself isn't an emergency, but the feelings that come with it can be. If you ever feel unable to keep yourself safe (NHS):
- call 999 or go to A&E if someone's life is at risk
- call NHS 111 and choose the mental health option (option 2 in England) for urgent help
- call Samaritans free, any time, on 116 123
Honest FAQs
What are the first signs of ADHD in adults?
Common signs include being easily distracted or forgetful, struggling to organise your time, leaving tasks unfinished, losing things, restlessness and acting on impulse (NHS). For ADHD, these traits usually go back to childhood.
Can you develop ADHD as an adult?
ADHD is a lifelong condition, so some symptoms need to have been present before age 12 for a diagnosis (Open University). Many adults are diagnosed for the first time later in life, often when coping strategies stop keeping up with demands.
How common is ADHD in adults?
NHS England estimates around 2.5 million people in England have ADHD, diagnosed or not (NHS England Digital). In a 2023/24 survey, 1.8% of adults said they had been diagnosed by a professional (NHS England Digital).
Can an online test tell me if I have ADHD?
No. Online questionnaires can suggest it's worth getting assessed, but only a specialist can diagnose ADHD after a full assessment (NICE NG87).
This article is general information, not medical advice. Always speak to a qualified clinician about your own symptoms.
