ADHD symptoms fall into two main groups — inattention, and hyperactivity/impulsivity — and a diagnosis requires a persistent pattern of these symptoms across more than one setting, not just occasional forgetfulness or restlessness. This page summarises what's typically assessed; only a qualified specialist can confirm a diagnosis.
This is written for two groups: people wondering whether their own experience matches ADHD closely enough to be worth a GP conversation, and parents or partners trying to understand a pattern they've noticed in someone else. Either way, the lists below are a starting point for that conversation, not a self-diagnosis tool.
Inattentive symptoms
Common inattentive symptoms include:
- Difficulty sustaining attention on tasks, conversations or reading
- Frequently losing or misplacing everyday items (keys, phone, paperwork)
- Struggling to follow through on instructions or finish tasks
- Poor organisation and time management
- Avoiding tasks that require sustained mental effort
- Being easily distracted by unrelated thoughts or surroundings
- Forgetfulness in daily activities, including appointments and commitments
Hyperactive and impulsive symptoms
Common hyperactive-impulsive symptoms include:
- Fidgeting, restlessness, or difficulty staying seated
- Feeling constantly "on the go" or driven by a motor
- Excessive talking or difficulty waiting for a turn in conversation
- Interrupting others or blurting out answers
- Acting without thinking through consequences
- Difficulty engaging in quiet activities
How symptoms differ between children and adults
In children, hyperactivity is often the most visible sign — running, climbing, or struggling to sit still in a classroom. In adults, this frequently shifts toward internal restlessness, difficulty unwinding, or a persistent sense of being mentally "busy," rather than obvious physical hyperactivity. See our dedicated adult ADHD guide for more detail on how presentation changes over time.
How symptoms are actually assessed
A specialist assessment doesn't just count symptoms from the lists above — it looks at how long they've been present, whether they started before age 12, whether they show up in more than one setting (home, school, work, relationships), and how much they actually interfere with daily functioning. Two people can tick similar boxes on a checklist and receive different outcomes, because the clinical threshold is about persistent, cross-situational impairment, not occasional difficulty.
This is also why standardised, validated rating scales are used alongside a clinical interview — they help structure the assessment consistently, rather than relying on a single conversation or a self-completed checklist alone.
Symptoms alone aren't a diagnosis
A genuine ADHD diagnosis requires more than matching a checklist — it requires symptoms that have been present since childhood, occur across multiple settings (not just one), cause measurable impairment, and aren't better explained by another condition. Several other conditions, including anxiety, depression and sleep disorders, can produce overlapping symptoms, which is exactly why a structured specialist assessment matters rather than self-diagnosis from a symptom list.
Preparing for a conversation with a GP
If you're considering raising this with a GP, it can help to prepare beforehand rather than trying to recall everything in the room. Useful things to note in advance:
- Which symptoms from the lists above feel familiar, and roughly how long they've been present
- Specific, recent examples in more than one setting — a missed deadline at work, a repeated pattern at home, feedback from a partner or colleague
- Whether anyone noticed similar patterns when you were a child, even if nothing was ever assessed at the time
- Any current diagnoses or medications, since these can overlap with or affect ADHD symptoms
You don't need a polished case — a GP's role at this stage is simply to listen and decide whether a specialist referral is appropriate, not to make the diagnosis themselves.
What to do next
If this list feels familiar and has done for as long as you can remember, the next step is talking to a GP about a referral for formal assessment. Our ADHD diagnosis guide walks through exactly how that process works in the UK, including the NHS and private routes.