ADHD Symptoms by Type and Age (Child to Adult)

The teacher calls you in and says your son "can't sit still and never finishes anything." On the drive home, you remember the car payment was due yesterday. Again. With money in the account.

That same week, a friend who is 38 tells you she was just diagnosed with ADHD after ten years of being treated for anxiety. Three stories, three ages, and the same list of symptoms wearing completely different clothes. This article is about recognizing the list underneath the clothes.

What are the symptoms of ADHD

ADHD symptoms fall into two groups: inattention (careless mistakes, unfinished tasks, lost belongings, forgotten appointments, easy distraction) and hyperactivity-impulsivity (restlessness, not staying seated, talking too much, interrupting, not waiting your turn). The DSM-5-TR lists nine symptoms in each group; the ICD-11 describes the same pattern.

The official list comes from the DSM-5-TR, the manual of the American Psychiatric Association. The WHO's ICD-11 uses code 6A05 and speaks of "a persistent pattern of inattention and/or hyperactivity-impulsivity that has a direct negative impact on functioning". The big picture (causes, types, treatment) is in what is ADHD. Here the subject is only the symptom: what the manual says, what it means in plain language, and what it looks like in a real scene.

The 9 symptoms of inattention

The nine inattention symptoms in the DSM-5-TR are: careless mistakes, difficulty sustaining focus, seeming not to listen, not finishing tasks, disorganization, avoiding sustained mental effort, losing things, being distracted by outside stimuli, and forgetting everyday activities. Every one of them begins with "often": what counts is the repetition, not the isolated episode.

Each one with the manual's wording, the practical meaning and a scene:

1. Careless mistakes. "Fails to give close attention to details or makes careless mistakes." The person knows the material and gets it wrong by skipping a sign. The scene: the spreadsheet sent with the wrong total, after being checked three times.
2. Can't sustain attention. "Difficulty remaining focused during lectures, conversations, or lengthy reading." The scene: reading the same page four times and remembering none of it.
3. Seems not to listen. "Mind seems elsewhere, even in the absence of any obvious distraction." The scene: the child looking straight at you while you explain, and two minutes later asking what they were supposed to do.
4. Doesn't finish what they start. "Starts tasks but quickly loses focus and is easily sidetracked." The scene: the bedroom half tidied, because halfway through an old book turned up.
5. Disorganization. "Poor time management; fails to meet deadlines; difficulty keeping materials and belongings in order." The scene: the backpack that became a black hole, the deadline discovered the night before.
6. Avoids sustained mental effort. Homework in the child; in the adult, "preparing reports, completing forms, reviewing lengthy papers". The scene: the tax return filed on the last day, after three weeks of "I'll do it tomorrow".
7. Loses things. The manual's list is painfully recognizable: "pencils, books, wallets, keys, paperwork, eyeglasses, mobile phones". The scene: the third student ID of the year.
8. Easily distracted. By outside stimuli and, in adolescents and adults, this "may include unrelated thoughts". The scene: the meeting where one sentence reminded you of a TV show, which reminded you of a trip, and you came back not knowing what was decided.
9. Forgets everyday things. In the adult, "returning calls, paying bills, keeping appointments". The scene: the car payment from the start of this article.

The 9 symptoms of hyperactivity and impulsivity

The nine hyperactivity-impulsivity symptoms are: fidgeting with hands and feet, leaving your seat, running or climbing (in the adult, inner restlessness), being unable to play or relax quietly, acting as if "driven by a motor", talking too much, blurting out answers before the question is finished, not waiting your turn, and interrupting. The first six are hyperactivity; the last three, impulsivity.

1. Fidgets. "Fidgets with or taps hands or feet or squirms in seat." The scene: the leg bouncing under the desk for the entire exam, without the person noticing.
2. Leaves the seat when expected to stay. In the classroom, in the office. The scene: the child who "went to sharpen a pencil" six times in the same lesson.
3. Runs or climbs. With the manual's most important caveat for adults: "in adolescents or adults, may be limited to feeling restless". The scene at 7: on top of the sofa. At 35: in the movie theater, counting the minutes until the film ends.
4. Can't play or relax quietly. The scene: the vacation where resting became an impossible task.
5. "Driven by a motor". "Is unable to be or uncomfortable being still for extended time, as in restaurants, meetings; may be experienced by others as being restless or difficult to keep up with." The scene: the coworker everyone describes as "intense".
6. Talks too much. The scene: the two-minute answer to a yes-or-no question.
7. Blurts out answers before the question is finished. "Completes people's sentences; cannot wait for turn in conversation." The scene: you already know how your boss's sentence ends, and you say it.
8. Can't wait their turn. "While waiting in line." The scene: the child who cuts the line for the slide; the adult who switches checkout lanes three times.
9. Interrupts or intrudes. "Butts into conversations, games, or activities"; in the adult, "may intrude into or take over what others are doing". The scene: the coworker's project you "just tidied up a bit" without anyone asking.

How the same symptom looks at each age

The symptom is the same; the setting changes. In preschool, motor restlessness dominates; in elementary school, inattention becomes visible, because school starts demanding focus; in adolescence, hyperactivity turns into inner restlessness and disorganization costs more; in the adult, what remains is inattention, impulsivity and forgetfulness. The table below shows this symptom by symptom.

That summary comes from the DSM-5 itself, as quoted in a report by the US National Academies: symptoms "range from the motor restlessness and disruptive behavior common in preschoolers to the disorganized, distracted, and inattentive symptoms more typical of older adolescents and adults".

In short, by stage:

The "invisible" symptoms: emotion, hyperfocus and time

Three things that anyone with ADHD recognizes instantly are not on the official list: difficulty regulating emotions, hyperfocus, and "time blindness". They are not diagnostic criteria, but the literature describes them as frequent features of the disorder, and they are often what gets in the way most in adult life.

Emotional dysregulation. The review by Katzman and colleagues (2017) states that "emotional dysregulation is a distinctive attribute of adult ADHD psychopathology": the irritation that rises too fast, the out-of-proportion frustration over a small setback, the outburst that passes in minutes. The 2021 international consensus records that methylphenidate reduces emotional dysregulation in adults with a small to moderate effect, a sign that it is part of the picture, not a separate problem.

Hyperfocus. It sounds like a contradiction: the person who cannot read one page spends six hours on a game or a project without getting up to eat. A study with two samples of adults (251 and 372 participants) found that people with higher ADHD symptoms report hyperfocus significantly more often, in study, hobbies and screens. It is not a lack of attention. It is attention without a steering wheel. The article on hyperfocus explains how to use it in your favor.

Time blindness. Russell Barkley describes the executive function deficit in ADHD as being to time what nearsightedness is to spatial vision: the person sees right now in sharp focus and two weeks from now as a blur. That is why the "distant" deadline turns urgent overnight. More in time blindness.

ADHD symptoms in girls and women

In girls, the most common symptom is inattention, not hyperactivity. Because the inattentive girl disturbs no one and often compensates with effort and good behavior, she is referred less, diagnosed later, and frequently receives a diagnosis of anxiety or depression first. The list of symptoms is the same; what changes is who notices.

The expert consensus on females with ADHD (Young et al., 2020) reports clinical referral ratios of boys to girls "ranging from 3:1 to 16:1", against about 3:1 in community samples, meaning a large share of girls with ADHD "likely remain unidentified and untreated". The "disruptive boy" stereotype, the document says, "likely influences the likelihood of referral"; and "compensatory behaviors in girls, such as socially adaptive behavior and compliance" mask the impairment.

The review by Hinshaw and colleagues describes girls who "compensate with intense effort and coping strategies, masking core impairments", and notes that the ratio of 2 to 2.5 boys per girl in childhood falls to about 1.5 to 1 or less in adult life. Quinn and Madhoo (2014) add that women "tend to be older than men when diagnosed" and that, with fewer symptoms counted by the criteria, they have the same degree of impairment. The article on ADHD in women goes deeper, including the role of hormones.

How many symptoms are needed for a diagnosis

Under the DSM-5-TR, you need six or more symptoms from the same group (inattention or hyperactivity-impulsivity) up to age 16, and five or more from age 17. They must persist for at least six months, have appeared before age 12, occur in two or more settings, and cause clear impairment in functioning.

One criterion does not fit in a number: the manual requires "clear evidence that the symptoms interfere with, or reduce the quality of, social, academic, or occupational functioning". That is what separates a trait from a disorder. Having six symptoms with no impairment is not ADHD; having five symptoms that wreck your school life may be. Everyone has some of these behaviors sometimes; the 2021 international consensus estimates that 5.9% of children and adolescents and 2.5% of adults meet full criteria. That is a lot of people, and a long way from "everyone".

The combination of the groups defines the presentation: predominantly inattentive, predominantly hyperactive-impulsive, or combined, and it can change over a lifetime, as the table above makes clear. The doctor also rates severity as mild, moderate or severe, depending on the number of symptoms beyond the minimum and the size of the impairment. The article on types of ADHD details each presentation.

When to seek help and which professional

Seek an assessment when the symptoms are clearly greater than those of people the same age, have lasted months, appear in more than one setting, and are costing something concrete: grades, a job, money, relationships, self-esteem. For children, a pediatrician, pediatric neurologist or child psychiatrist; for adults, a psychiatrist or neurologist. In many countries your family doctor or GP is the first stop and makes the referral. Psychologists run the assessment that supports the diagnosis.

ABDA, the Brazilian ADHD association, is direct about the method: "the diagnosis is entirely clinical, based on symptoms", made by "psychiatrists, neurologists and pediatric neurologists", and "no MRI, EEG or any other exam is needed". The SBP repeats it: "there is no exam or psychological test that allows the diagnosis to be made". Guidelines elsewhere (NICE in the UK, the American Academy of Pediatrics in the US) describe the same method. In practice: a long interview, accounts from people who live with you (parents, teachers, a partner), and ruling out other causes, such as anxiety, depression and poor sleep.

For students in Brazil, Law 14,254/2021 guarantees comprehensive support to anyone with ADHD or dyslexia, including "early identification of the disorder, referral of the student for diagnosis" and support within the school system; the school can and should be a partner. Elsewhere, look for the local equivalent: in the US, a 504 plan or IEP; in the UK, SEN support through the school. For adults, the ASRS screening test is an honest starting point to bring to the appointment, not a verdict.

A tip for the appointment: arrive with examples. Not "I'm disorganized", but "in September I paid three bills late and missed two deadlines at work". The professional needs scenes, and the ADHD memory is exactly what fails to deliver scenes on demand. Write them down for a week or two beforehand.

The problem that remains

Notice the pattern: almost everything this article describes is a failure to bring the right thing to mind at the right time. The bill was not forgotten for lack of money; the homework was not left half done for lack of ability. And the advice to write down examples for the appointment has the weak spot of every ADHD strategy: it depends on remembering to write them down.

That is what made me build ASB. Sofia, the assistant, lives on WhatsApp: you send a voice note on the way home ("car payment, the 10th"), she turns it into a task with a deadline, and at the right moment she calls. And she insists, at the level you choose, until the thing is done. It is not a new filter for attention; it is someone on the outside, bringing the information at the moment it matters.