Signs of ADHD in adults: common symptoms and when to get tested

Plenty of adults lose their keys, put off boring paperwork or drift off in long meetings. That alone isn't ADHD. But if those things have been happening for as long as you can remember, and they keep costing you at work, at home or in your relationships, it's a fair question to ask.

Here's what adult ADHD tends to look like in everyday life, why it so often goes unnoticed until adulthood, and how to find out whether it explains what you're dealing with.

What is ADHD, and how is it diagnosed?

ADHD (attention-deficit/hyperactivity disorder) is a neurodevelopmental condition. Clinicians diagnose it using the DSM-5 criteria published by the American Psychiatric Association. There are two groups of symptoms: inattention, and hyperactivity-impulsivity.^[1]

For someone aged 17 or older, a diagnosis needs all of the following:^[1]

• At least five symptoms from one or both groups (children need six).
• Symptoms that have lasted at least six months.
• Several symptoms present before age 12.
• Difficulties in more than one setting, such as work and home.

Depending on which symptoms dominate, the diagnosis is recorded as one of three presentations: predominantly inattentive, predominantly hyperactive-impulsive, or combined.^[1]

One point people often miss: ADHD can only be diagnosed by a licensed clinician who interviews you. The World Federation of ADHD's consensus statement is blunt about it. Rating scales, computer tests and brain scans can't make the diagnosis on their own.^[5]

How common is ADHD in adults?

The answer depends on how you count. Studies that require symptoms to have started in childhood find lower numbers than studies that count anyone with current symptoms. Surveys of who has been diagnosed give a third figure.

That CDC survey, published in 2024, estimated that about 15.5 million US adults had a current ADHD diagnosis. Of those, 55.9% were diagnosed at age 18 or older.^[2] Being diagnosed as an adult is common now.

ADHD symptoms do tend to ease with age. A meta-analysis summarized in the World Federation of ADHD statement found that only about one in six young people with ADHD still met full criteria at age 25, while about half still had some impairing symptoms.^[5]

What are the signs of ADHD in adults?

The DSM-5 lists nine inattention symptoms and nine hyperactivity-impulsivity symptoms. Here they are in plain language, from the American Psychiatric Association's summary:^[1]

Inattention

• Missing details or making careless mistakes
• Trouble staying focused on tasks, reading or conversations
• Seeming not to listen when spoken to directly
• Not following through on instructions, or leaving tasks unfinished
• Poor organization and time management
• Avoiding tasks that need long stretches of mental effort
• Often losing things you need
• Being easily distracted
• Forgetting daily tasks, appointments or bills

Hyperactivity and impulsivity

• Fidgeting or squirming
• Getting up when you're expected to stay seated
• Feeling restless (in children this is running or climbing)
• Finding it hard to do things quietly
• Feeling constantly "on the go"
• Talking a lot
• Blurting out answers
• Finding it hard to wait your turn
• Interrupting or intruding on others

In adults, hyperactivity often fades or turns inward. The APA notes it can show up as extreme restlessness, while inattention is more likely to persist.^[1] So an adult with ADHD might sit through a meeting without moving and still feel like they're crawling out of their skin.

That shift is one reason adults sometimes don't recognize themselves in descriptions of ADHD written with children in mind. The criteria are the same at any age, but what they look like changes:

The table below gives examples of how the same signs can play out in different parts of life.

Emotional ups and downs

Many adults with ADHD also describe quick frustration, irritability or feelings that hit hard and fade fast. This is usually called emotion dysregulation. It isn't one of the DSM-5 criteria, so it doesn't count toward a diagnosis. Still, a review in the American Journal of Psychiatry found that clinic studies report impairing emotion dysregulation in 34% to 70% of adults with ADHD.^[6] If this part sounds familiar, mention it during an assessment.

Why is ADHD often missed in women?

ADHD is diagnosed more often in males, roughly two to one in young people.^[5] Part of that gap seems to come from girls and women being overlooked. A 2020 expert consensus statement from the UK ADHD Partnership points to several reasons:^[7]

• Inattentive symptoms, such as being easily distracted, disorganized or overwhelmed, are less likely to lead to a referral than disruptive behaviour. Inattentive girls are more often missed.
• Teachers' and parents' expectations about how ADHD looks affect who gets referred.
• Coping strategies, like over-preparing or working much longer hours, can hide the underlying difficulty. People often call this masking.
• Co-occurring conditions, such as anxiety, depression or eating disorders, can overshadow the ADHD.

The same statement notes that symptoms may become more obvious during transitions, such as starting university or a new job, and can get worse with hormonal changes across the menstrual cycle, pregnancy and menopause.^[7] Many women only start asking about ADHD as adults, when the demands on them outgrow the coping strategies that used to work.

Can you have ADHD if you did well at school?

Yes. Good grades don't rule it out. The UK consensus statement describes how compensatory strategies, at home or at school, can mask symptoms, and advises assessors to look at what support or structure was in place.^[7] Say a parent kept your schedule for you, or you got by on last-minute bursts of effort. The difficulty may only become obvious once that support is gone or the workload grows.

What else can look like ADHD?

There's no single test for ADHD, and the CDC lists sleep disorders, anxiety, depression and some learning disabilities as conditions that can produce similar symptoms.^[11] A good assessment checks for these. The table shows some ways they tend to differ, though real life is messier, and you can have more than one.

If anxiety or low mood sounds closer to your experience, our anxiety test (GAD-7) and depression test (PHQ-8) use the same short questionnaires many doctors use. ADHD and autism also share traits, which we cover in ADHD vs. autism in adults.

What conditions often come with adult ADHD?

ADHD rarely travels alone. In the US National Comorbidity Survey Replication, adults with ADHD often had at least one other condition, most commonly an anxiety or mood disorder.^[4]

That survey also found that only 10.9% of adults with ADHD had received treatment for ADHD in the previous year, even though many had been treated for other conditions.^[4] That study is now 20 years old, and diagnosis has become more common since. Even so, in the 2023 CDC survey, 36.5% of adults with a current ADHD diagnosis had received no ADHD treatment in the past year.^[2]

What can an online ADHD test tell you?

Many online ADHD tests, ours included, follow the format of the WHO Adult ADHD Self-Report Scale (ASRS), developed by the World Health Organization with researchers at Harvard Medical School. It asks how often you've had each symptom over the past six months. Its research record is mixed:

• In the original 2005 study, the six-question ASRS screener correctly identified 68.7% of people with ADHD (sensitivity) and correctly cleared 99.5% of people without it (specificity).^[8]
• A 2017 version updated for DSM-5 did better, with 91.4% sensitivity and 96.0% specificity in general population samples.^[9]
• But when researchers gave the ASRS v1.1 to general population samples in the UK and US, it flagged 26.0% and 17.3% of people as probable ADHD, against an expected rate of about 2.5%. They estimated that only about 11.5% of positive screens would turn out to be ADHD.^[10]

Put simply, a high score means it's worth talking to a professional. It doesn't mean you have ADHD, because stress, anxiety, low mood, poor sleep and other impulse-related problems can all push scores up. A low score makes ADHD less likely, but if your difficulties are real and long-standing, a low score shouldn't stop you from asking for help.

On our ADHD test, each of the 18 answers scores from 0 (never) to 4 (very often), for a total out of 72. Scores of 29 to 44 suggest some ADHD traits, and 45 or more suggest many. You also see separate scores for inattention and for hyperactivity-impulsivity, which can help a clinician see where your difficulties cluster. Treat those numbers as a starting point for a conversation.

How do adults get assessed for ADHD?

The details vary by country and health system, but most adult assessments follow a similar path. The DSM-5 criteria shape what the clinician asks about.^[1][5]

How is adult ADHD treated?

Treatment usually means medication, therapy and practical support, alone or combined. In a large network meta-analysis summarized by the World Federation of ADHD, stimulants (amphetamines and methylphenidate) reduced adult symptoms compared with placebo, and atomoxetine, a non-stimulant, had moderate benefits. For psychological treatment, a meta-analysis of cognitive behavioral therapy for adults found moderate improvements in self-reported symptoms, though effects were small in the most rigorous trials.^[5] The NIMH lists medication and psychosocial treatments, such as cognitive behavioral therapy, as the standard options.^[12] In the US, adults whose symptoms affect their work may also qualify for workplace accommodations.^[1] Which mix makes sense depends on your health, your other conditions and what you prefer, so it's a decision to make with a clinician.

When should you get tested for ADHD?

It's worth asking for an assessment if most of these are true:

• Several of the signs above happen often, not just during stressful weeks.
• You can trace them back to childhood, even if they looked different then.
• They cause problems in more than one area, such as your job and your home life.
• Other explanations, like poor sleep or a period of depression, don't fully account for them.

If you're not sure, a screener is a reasonable first step. Take the result to a doctor along with your examples. And if you're struggling with your mood or feel unsafe, contact a doctor or a crisis line now, before any ADHD question.