For decades, one of the greatest challenges to treating neurological disorders like attention-deficit/hyperactivity disorder is that its symptoms often resemble those of several other conditions. Overlapping disorders are extremely common when it comes to neurological diagnoses.
A child who struggles to sit still, focus or complete tasks could have ADHD, anxiety, a learning disability or simply be reacting to stress at home. A teenager who seems emotionally volatile and impulsive might be showing early signs of a mood disorder, ADHD or trauma. An adult who constantly misses deadlines, forgets important obligations and feels chronically overwhelmed might be dealing with workplace burnout, a severe anxiety disorder or undiagnosed ADHD.
I am a practicing psychiatrist at the National Medical Center “20 de Noviembre” in Mexico City, and a professor of medicine at UNAM, the National Autonomous University of Mexico. In my work, I frequently see cases that initially look like anxiety, but I often find that this issue is only the tip of the iceberg. Anxiety improves, and what emerges is undiagnosed ADHD.
The reverse can also be true: What looks like ADHD — difficulty focusing, restlessness, poor performance — sometimes turns out to be driven primarily by anxiety. However, in my practice, I most frequently see the opposite scenario. Young adults arrive seeking treatment for severe anxiety, but clinical evaluation often shows that their condition is rooted in executive functions – such as planning and problem-solving – that have been fragile since childhood. Patients in this situation have compensated for their undiagnosed ADHD for years through exhausting effort and the fear of failure.
Diagnosing untreated ADHD matters because in adults, this condition is associated with depression, anxiety, work difficulties, academic problems and financial stress.
Because these conditions are so tightly interwoven, it is not always possible to know which came first — and in many cases, both are genuinely present at the same time. Treating only what is visible may bring real but only partial relief, leaving the underlying driver unaddressed.
This is why evaluation by a clinician who can assess the full picture matters. When ADHD is properly identified and treated, secondary anxiety often resolves more completely than it ever did with therapy or medication alone. But the reverse is not reliably true: Treating anxiety does not correct the underlying attention issues that may be driving it. Identifying the right target – or targets – is what leads to lasting improvement. This comprehensive approach is especially important given the growing recognition that emotional dysregulation – such as intense, rapid mood shifts or an inability to manage one’s distress – is often a core, yet historically overlooked, symptom of undiagnosed ADHD.
Here’s why undiagnosed ADHD can hide behind anxiety, some signs that can help differentiate these two conditions, and why this diagnostic blind spot – treating the visible anxiety while missing the underlying ADHD – is so common.
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Table of Contents
How ADHD lurks
I had been seeing a patient in his late 20s for some time who suffered from anxiety when he came to an appointment convinced that he was finally emerging from a terrible year. He had stopped having panic attacks, was sleeping better and no longer lived intensely focused on his own body, waiting for the next wave of fear. After months of antidepressants and cognitive behavioral therapy, the crises seemed controlled.
But then something different emerged: constant difficulty concentrating, procrastination that left him stuck for hours, impulsive speech and a stubborn inner restlessness. These symptoms are often overshadowed when someone feels suffocated by anxiety and consumed by worries.
Anxiety and ADHD have many common symptoms, including restlessness, irritability, sleep difficulties and concentration problems. This overlap can lead to diagnostic errors and treatments that don’t address the root cause.
During childhood, many ADHD symptoms are interpreted as personality traits. A child may be labeled as distracted, inconsistent, impulsive or restless. Over time, these people learn to compensate through excessive effort, perfectionism or constant self-monitoring – strategies that raise baseline stress and may trigger anxiety years later.
When the brain leaves survival mode
Anxiety is often the first way the body expresses overload. When this threat response eases, previously masked struggles with planning, organization, sustained attention and time management surface.
Several studies show a strong association between ADHD traits, anxiety and depression. In the United Kingdom, recent research found that ADHD traits predict emotional problems more strongly than traits related to the autism spectrum.
Systematic reviews indicate that 25% to 50% of adults with ADHD experience an anxiety disorder at some point in their lives. Major depressive disorder is also more common among this group than in the general population. For many people, anxiety is the consequence of years trying to function with an impaired executive system, the part of the brain that manages planning, organization and impulse control.
Why ADHD can elude early detection
It can be easy for parents, teachers or co-workers to misinterpret ADHD symptoms as character traits. Impulsivity can be seen as bad temper, disorganization as laziness, and difficulty maintaining attention as lack of interest. In adults, these difficulties are often interpreted as personal flaws rather than neuropsychiatric disorders.
ADHD rarely causes physical symptoms, but anxiety does. Heart palpitations, intense fear or insomnia drive people to seek care, while attention symptoms are less recognized.
ADHD is strongly genetic, with inheritance rates estimated at 70% to 80%. This genetic component also means that closely related relatives have a higher risk of emotional disorders such as anxiety and depression. When several family members share similar traits, these attributes often are considered part of the family personality.
Primary anxiety versus anxiety due to ADHD
The key question in clinical practice is this: What remains when the anxiety decreases?
If emotional distress diminishes but the following symptoms persist, then the pattern aligns more with adult ADHD:
– prolonged procrastination
– difficulty initiating tasks requiring mental effort
– frequently forgetting instructions or appointments
– constant inner restlessness
– daily disorganization
– easy distraction by minimal stimuli
A formal diagnosis, made by a trained health professional, requires an assessment of symptoms that have been present since childhood and a determination that the patient is impaired in more than one life area. Caregivers will rule out other medical or psychiatric causes, using validated tools such as structured interviews and specific scales.
Neurobiological studies have shown that people with ADHD have identifiable differences in several brain regions, including their connections in the deep neural tissue known as white matter and the reward circuitry of the brain. They also have imbalances in dopamine and norepinephrine — brain chemicals that regulate attention, motivation and impulse control. These differences can make it harder for people to initiate tasks or sustain efforts.
The risk of treating only what is visible
Antidepressants and therapy can reduce emotional distress and overlapping symptoms such as restlessness or sleep disruption, but they do not modify the attention difficulties that create daily chaos – affecting relationships, academic performance and work functioning. If this root is not addressed, the patient improves partially but continues living in disorganization, leading to new cycles of distress.
When I explain how anxiety can mask ADHD to patients, their most common reaction is a mix of relief and frustration. They finally understand their emotional history, but see that they spent years interpreting their symptoms and struggles as flaws.
Studies show that adults with anxiety and untreated ADHD suffer greater functional impairment and more frequent relapses, meaning their severe anxiety or depressive episodes keep returning despite therapy or medication. They live under a burden of self-reproach that harms their self-esteem. This cycle can repeat for years: emotional improvement, relapse and seeking treatment again, without identifying the main problem.
The good news is that once ADHD is diagnosed, it is treatable. Robust evidence shows that treatment for ADHD reduces impulsivity and improves sustained attention and daily functioning at all ages.
Regulating dopamine and norepinephrine enables patients to initiate tasks and sustain their efforts until the work is completed. When this happens, secondary anxiety often decreases more deeply and stably because people no longer have to work twice as hard just to keep up. This also improves their relationships at home, school and work.
Identifying hidden ADHD does not erase the past, but it changes the future. When people understand the root cause of their anxiety and gain tools to manage it, they can move from surviving to living a more functional life.
