For decades, one of the biggest challenges in treating neurological disorders such as attention deficit/hyperactivity disorder is that its symptoms often resemble those of many other conditions. Overlapping disorders are extremely common when it comes to neurological diagnoses.
A child who has trouble sitting still, focusing, or completing tasks may have ADHD, anxiety, a learning disability, or simply be reacting to stress at home. A teen who seems emotionally unstable and impulsive may be showing early signs of a mood disorder, ADHD, or trauma. An adult who constantly misses deadlines, forgets important obligations, and feels chronically overwhelmed may be dealing with workplace burnout, severe anxiety disorder, or undiagnosed ADHD.
I am a practicing psychiatrist at the National Medical Center “20 de Noviembre” in Mexico City and professor of medicine at UNAM, the National Autonomous University of Mexico. In my work, I often see cases that at first look like anxiety, but I often find that this issue is only the tip of the iceberg. The 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 mostly due to anxiety. However, in my practice, I see the opposite scenario more often. Young adults arrive seeking treatment for severe anxiety, but clinical assessment often shows that their condition is rooted in executive functions – such as planning and problem solving – that were fragile from childhood. Patients in this condition have for years compensated for their undiagnosed ADHD through exhausting effort and fear of failure.
Diagnosing ADHD without treatment is important because in adults, this condition is associated with depression, anxiety, work difficulties, academic problems and financial stress.
Because these conditions are so closely intertwined, it is not always possible to know which came first—and in many cases, both are truly present at the same time. Treating only the visible can bring real but only partial relief, leaving the underlying driver indifferent.
This is why evaluation by a clinician who can assess the whole picture matters. When ADHD is recognized and properly treated, secondary anxiety often resolves more completely than ever with therapy or medication alone. But the reverse isn’t reliably true: Treating anxiety doesn’t fix the underlying attention issues that may be driving it. Identifying the right goal – or goals – is what leads to continuous improvement. This integrated approach is particularly important given that growing recognition that emotional dysregulation – such as severe, rapid mood swings or an inability to manage one’s distress – is often a key, but historically overlooked, symptom of undiagnosed ADHD.
Here’s why undiagnosed ADHD can be hidden behind anxiety, some signs that can help differentiate the two conditions, and why this diagnostic blind spot—treating visible anxiety while missing the underlying ADHD—is so common.
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How does ADHD lurk?
I had been seeing a patient in his late 20s for quite some time who suffered from anxiety when he came to an appointment convinced that he was finally coming off a terrible year. He had stopped having panic attacks, slept better and no longer lived intensely focused on his body, waiting for the next wave of fear. After months of antidepressants and cognitive behavioral therapy, the seizures seemed under control.
But then something different emerged: constant difficulty concentrating, procrastination that left him stuck for hours, impulsive speech, and a persistent inner restlessness. These symptoms are often overshadowed when one feels suffocated by stress and consumed by worry.
Anxiety and ADHD they have many symptoms in commonincluding restlessness, irritability, difficulty sleeping and problems concentrating. This overlap can lead to diagnostic errors and treatments that do not address the root cause.
During childhood, many symptoms of ADHD are interpreted as personality traits. A child may be characterized as distracted, inconsistent, impulsive, or anxious. Over time, these people learn to compensate with over-effort, perfectionism, or constant self-control—strategies that add to initial stress and can cause anxiety years later.
When the brain abandons survival mode
Stress is often the first way the body expresses overload. When this threat response relaxes, previously masked struggles with planning, organization, sustained attention, and time management surface.
Several studies show a strong correlation between ADHD features, anxiety and depression. In the United Kingdom, recent research found that the characteristics of ADHD predict more intense emotional problems rather than characteristics associated with the autism spectrum.
Systematic reviews show that 25% to 50% of adults with ADHD experience an anxiety disorder at some point in their lives. Major depressive disorder is also more often in this group than in the general population. For many people, stress is the consequence of years of trying to function with a person with a disability executive systemthe part of the brain that manages planning, organization, and impulse control.
Why ADHD can escape early detection
It can be easy for parents, teachers, or coworkers to mistake ADHD symptoms for character traits. Impulsivity can be seen as a bad temper, disorganization as laziness, and difficulty sustaining attention as a 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 prompt people to seek care, while attention symptoms are less recognized.
ADHD is highly genetic, with high heritability rates estimated at 70% to 80%. This genetic component also means that Close relatives have a higher risk of emotional disorders such as anxiety and depression. When several family members share similar characteristics, these characteristics are often taken into account part of the family personality.
Primary anxiety vs ADHD anxiety
The key question in clinical practice is this: What remains when stress is reduced?
If the emotional distress decreases but the following symptoms persist, then the pattern more closely aligned with adult ADHD:
– prolonged procrastination
– difficulty starting tasks that require mental effort
– you often forget instructions or appointments
– constant inner restlessness
– daily disorganization
– easily distracted by minimal stimuli
A formal diagnosis, made by a trained health professional, requires an evaluation of symptoms that have been present since childhood and a finding that the patient is impaired in more than one area of life. 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 areas of the brain, including their connections in the deep neural tissue known as white matter and the brain’s reward circuitry. 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 start tasks or sustain efforts.
The danger of treating only the visible
Antidepressants and therapy can reduce emotional distress and overlapping symptoms, such as restlessness or sleep disturbance, but 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 partially improves but continues to live in disorganization, leading to new cycles of distress.
When I explain how stress can mask ADHD to patients, their most common reaction is a combination of relief and disappointment. 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 relapsesmeaning that severe episodes of anxiety or depression keep coming back despite treatment or medication. They live under a burden of self-blame which damages their self-esteem. This cycle can repeat itself for years: emotional improvement, relapse, and seeking treatment again, without identifying the underlying problem.
The good news is that once ADHD is diagnosed, it is treatable. Strong evidence suggests that treatment for ADHD reduces impulsivity and improves sustained attention and daily functioning at all ages.
Regulation of dopamine and norepinephrine enables patients to initiate tasks and sustain their efforts until the task is completed. When this happens, secondary stress is often reduced more deeply and steadily because people no longer have to work twice as hard to keep up. This also improves their relationships at home, school and work.
Identifying hidden ADHD does not erase the past, but changes the future. When people understand the root cause of their stress and gain tools to manage it, they can move from survival to a more functional life.
