Attention deficit hyperactivity disorder, or ADHD, misdiagnosis can happen because many of its symptoms overlap with those of other conditions. The symptoms of ADHD — such as difficulty concentrating, restlessness, and finding it hard to respond to instructions — can all arise from a wide variety of causes.
Some aspects of ADHD may also be symptoms of other conditions. Due to the complex nature of the condition, some people may receive an incorrect diagnosis.
This is due to a wide range of diagnostic issues. Here, we look at some of the factors and conditions that can lead to a misdiagnosis of ADHD.
Doctors can misdiagnose ADHD in children due to their age. In fact, children who start school at a younger age more frequently receive a diagnosis of ADHD.
If a child starts school having just turned 5 years old while some of their peers are closer to 6 years old, there is an approximate 20% difference in age.
One study found that children born in December, which was the school cutoff age, were more likely to have an ADHD diagnosis than those born in January.
The date a child is born does not affect their chance of ADHD, as it is a neurodevelopmental condition. What this research does suggest, however, is that misdiagnosis can happen depending on the maturity levels of a developing child when they receive a diagnosis.
It is also important to note that having difficulty paying attention and being overactive may be normal behavior for children of a certain age.
Some research has found that boys receive a diagnosis of ADHD more often than girls, with a ratio ranging from 3:1 to 9:1 of boys to girls with an ADHD diagnosis.
Researchers suggest that this is because girls tend to display more symptoms of inattention than boys. Boys may instead show symptoms of hyperactivity, which are more noticeable.
More obvious displays of the symptoms of ADHD may result in an ADHD diagnosis.
Mood disorders include:
- bipolar disorder
- dysthymia, which is a chronic low or irritable mood lasting for 2 years or more in adults and at least 1 year in children
Some theories suggest that mood disorders can occur due to an imbalance of chemicals in the brain, stressful life events, or as a response to major illness or medication.
Some symptoms of mood disorders can be similar to those of ADHD, such as:
- difficulty concentrating
- difficulty sleeping
A psychologist, psychiatrist, or other mental health professional can diagnose a mood disorder by conducting an assessment and applying diagnostic criteria to a person’s symptoms.
Autism, also called autism spectrum disorder (ASD), can have some symptoms that may appear similar to ADHD.
These can include:
- fidgeting and always being on the move
- struggling in social interactions
- becoming upset due to frustration
ASD is a neurodevelopmental condition that affects communication, behavior, and social skills.
Symptoms of ASD can include:
- avoiding eye contact
- disliking changes in routine
- having difficulty with social skills
- using movement to soothe oneself, such as rocking the body or waving the arms
- having a restricted or fixed interest in certain topics or hobbies
- having difficulty empathizing with others
- not speaking, delayed speaking, or repeating certain phrases
Healthcare professionals such as neurologists and psychologists can carry out a detailed examination to diagnose ASD.
Some of the symptoms of anxiety disorders can be similar to those of ADHD, such as:
- difficulty concentrating
- feeling irritable
- struggling with social skills due to social anxiety
Anxiety disorder can also cause people to feel uncontrollable worry, become tired quickly, or have an excessive fear about a particular situation or object.
A doctor or psychotherapist can diagnose anxiety disorder by taking a thorough medical history and applying diagnostic criteria to the person’s symptoms.
- difficulty in concentrating
- daytime sleepiness
- decrease in performance at school or work
People with insomnia have difficulty falling or staying asleep.
OSA is a condition wherein the upper airway keeps getting blocked while asleep, which restricts airflow. People with OSA may:
- snore loudly
- gasp for air in their sleep
- frequently wake in the night to urinate
A doctor may take a medical history, carry out a physical examination, and suggest a sleep study — during which they can monitor activity during sleep — to diagnose a sleep condition.
Auditory processing disorder (APD) is a condition that makes it difficult for people to understand the sounds of words correctly. APD affects the way a person’s central nervous system interprets information.
People with ADHD can correctly process auditory information through their central nervous system; it is the deficit of attention that impacts how they take in and use that information.
Symptoms can be similar to ADHD and may include:
- difficulty listening, especially in noisy settings
- difficulty following spoken instructions
- asking for people to repeat speech, which may appear similar to having difficulty hearing
- difficulty receiving verbal information
A doctor cannot diagnose APD by looking at symptoms alone, as there may be many other causes for the communication, language, or learning difficulties.
An audiologist can diagnose APD by carrying out a variety of tests that look at responses to sound.
Allergies and celiac disease can create symptoms similar to those of ADHD.
In children, celiac disease can cause irritability and behavioral issues. In adults, celiac disease can cause fatigue, depression, and anxiety.
A 2011 study looked at 67 people ages 7–42. Out of the 67 participants, 10 had celiac disease. After 6 months of following a gluten-free diet, those with celiac disease had large improvements in their ADHD symptoms.
Untreated celiac disease may increase the likelihood of symptoms of ADHD. The researchers suggest that people should get tested for celiac disease as part of an ADHD diagnosis to help prevent a misdiagnosis.
Some other conditions that can present similar symptoms to ADHD include:
Because many of the symptoms of ADHD overlap with those of many other conditions, misdiagnosis can occur.
If ADHD is not the cause of the symptoms, they can become worse with the stimulants the doctor prescribes for treatment.
If a person displays symptoms of ADHD, it is important that they talk to their healthcare provider and go through a variety of tests to ensure that they receive the correct diagnosis and treatment.