ADHD or anxiety: what sets them apart

ADHD describes a lasting way of functioning: attention, organisation and activity level depart from what is expected, and they keep doing so. The World Federation of ADHD consensus statement, published in 2021 by Faraone and colleagues, notes that the criteria require signs that first appeared in early to mid-childhood and that show up in different settings, home and school for instance. An anxiety disorder describes something else: worry or fear that settles in, often around identifiable topics or situations.

So the difference lies less in the symptoms themselves than in their history. One sentence, “I cannot concentrate”, can describe attention that has never stayed put and attention that is fully taken up by something else. The table below places the tendencies most often described on each side next to one another.

Three reasons stack up, and none of them is incidental. Together they explain why the question keeps coming back, and why short questionnaires cannot resolve it.

• The visible signs overlap. Inner restlessness, difficulty holding a task, sleep that will not come appear in both descriptions, in almost the same words.
• Each can produce the other. Constant worry occupies working memory and degrades attention; conversely, years of forgotten deadlines build a lasting apprehension of any situation where something might be missed.
• The two often show up together. The review published in 2025 in Frontiers in Psychiatry puts the share of adults with ADHD who also have an anxiety disorder at between 25% and 50%.

Sleep is the clearest example. Delayed sleep onset and nights of fewer than six hours are common among adults who present both pictures, according to that same 2025 review. Lack of sleep then degrades attention and feeds worry, which supplies both descriptions at once and muddies any questionnaire answered on a Monday morning.

Yes, and it is common. The US national survey published in 2006 by Kessler and colleagues found that, over the preceding twelve months, 47.1% of adults meeting ADHD criteria also met criteria for an anxiety disorder. The same survey programme puts at 28.8% the share of people who will experience an anxiety disorder across their whole lifetime, all profiles taken together. The two figures are not directly comparable, one covers twelve months and the other a lifetime, but the gap is still wide.

This overlap has a concrete and little-known consequence. The review by Katzman and colleagues, published in 2017 in BMC Psychiatry, observes that ADHD is recognised later in people who also have an anxiety disorder: anxiety holds back impulsivity, so the signs that would have drawn attention earlier are less visible.

An assessment carried out by a health professional does not turn on a score, it turns on a reconstruction. It takes time because it looks for what best explains the difficulties, including explanations that have nothing to do with either of the two pictures compared here.

• How far back it goes: the age of the first remembered difficulties, and whether primary school already carried a trace of them.
• The settings: whether the same difficulties appear at work, at home and in leisure, or only in certain situations.
• What triggers and what relieves: a deadline, a social setting, a change of rhythm, a stretch of time off.
• Sleep, alcohol and caffeine intake, thyroid function, a deficiency: several causes produce neighbouring pictures.
• The real cost: what the difficulties take out of daily life, rather than how intense they feel on a scale.
• Life periods: a move, a bereavement, an exceptional workload, a pregnancy or menopause.

One popular shortcut deserves correcting: “ADHD starts in childhood and anxiety starts later” is too simple to be used on its own. In that same US survey, the median age at which anxiety disorders begin, all forms taken together, is 11 years. How far back the difficulties go matters a great deal, but it is not enough to separate the two.

1. Take a sheet of paper and make two columns: what was already there in primary school, what appeared later. Three to five dated examples are worth more than a general impression.
2. Notice what relieves it. If a week off changes everything, a temporary load is worth considering; if nothing shifts, write that down just as carefully.
3. Track your sleep for two weeks, bedtime and the hour you actually fall asleep. It is the variable that muddies both pictures the most.
4. Answer the self-observation questionnaires listed at the end of this page, both rather than one: two readings side by side say more than a single score.
5. Bring your notes and both results to your family doctor. They are the ones who refer you, and since waiting times are often long, starting early saves months.