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The Tip of the ADHD Iceberg – When it’s More Than ADHD

It can be difficult to diagnose Attention Deficit Hyperactivity Disorder (ADHD) when the symptoms presented are also common across other conditions. These are known..
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The Tip of the ADHD Iceberg – When it’s More Than ADHD


It can be difficult to diagnose Attention Deficit Hyperactivity Disorder (ADHD) when the symptoms presented are also common across other conditions. These are known as comorbid conditions or comorbidities. Some of the most common conditions comorbid with ADHD are:

  • Depression
  • Anxiety
  • Eating disorders
  • Obsessive-compulsive disorder (OCD)
  • Autism
  • Sensory processing disorder
  • Learning disabilities
  • Sleeping disorders

These other issues can disguise ADHD and lead to misdiagnosis. It’s always worth looking for other related conditions when symptoms don’t make sense on their own.

ADHD is more complicated than many people believe, with a wide range of symptoms that can be very challenging. There’s a popular analogy about ADHD being like an iceberg, in that what you can see on the surface, is just a glimpse of what is hidden below. There’s a misconception that ADHD merely means that someone can’t concentrate and is hyperactive. What isn’t as widely considered, is all the different ways that ADHD can impact a person’s life. Sometimes it’s the issues below the tip of the iceberg that lead someone to seek out a diagnosis. Comorbid conditions of ADHD share many of these features that are concealed below the water and this can lead to an incomplete diagnosis when other conditions remain unidentified.

ADHD and Depression

It’s estimated that up to 80% of people with ADHD will have at least one other related psychiatric condition within their lifetime. The most common conditions that co-occur alongside ADHD are depression and anxiety. Depression can be an extremely debilitating and dangerous condition if not treated properly and can be easily missed if symptoms are thought to be a result of ADHD, rather than independent of ADHD.

Depression can be missed when ADHD is diagnosed or vice-versa. This is because the two conditions share some of the same symptoms, such as:

  • Persistent sadness or irritability
  • Loss of interest in activities
  • Changes in appetite or body weight
  • Sleeping too little or too much
  • Fatigue
  • Difficulty concentrating
  • Suicidal thoughts

ADHD and Anxiety

An estimated 25-40% of people with ADHD may also have anxiety that requires separate treatment. 

Some overlapping symptoms of anxiety and ADHD are:

  • Persistent worrying
  • Physical symptoms
  • Difficulty sleeping
  • Irrational fears
  • Avoiding places and situations
  • Difficulty paying attention and focusing
  • Difficulty with change and transition

These symptoms need to be addressed in context by a qualified and experienced professional to determine if their cause is independent of ADHD.

ADHD and Eating Disorders

People with ADHD are at risk of developing eating disorders. There are various reasons for this: ADHD can lead to poor impulse control and difficulties regulating emotions. Food can be used to stimulate emotions by comfort eating and not everyone is aware of being full or hungry which can lead to overeating or skipping meals.

If someone with an eating disorder also has ADHD, it’s important to treat both conditions for treatment to succeed. Stimulant medications are commonly used to treat ADHD; they have also been found to help patients with bulimia to control binge eating as they promote impulse control.


Obsessive-Compulsive Disorder (OCD) and ADHD share some symptoms and can impact people’s lives in similar ways. Both conditions:

  • Involve the same brain areas
  • Can interfere with academic and career success
  • Affect attention
  • Impact relationships with others
  • Are associated with sleep problems
  • Are associated with gastrointestinal issues such as irritable bowel syndrome

However, ADHD and OCD occur in distinctly different ways; ADHD is externalising which means it occurs as someone responds and interacts with their environment, whereas OCD is internalising, as people use obsessive thoughts and compulsions to internally control situations.

According to one study there are more instances of OCD being misdiagnosed as ADHD than vice-versa. As stimulant medications prescribed for ADHD may exacerbate OCD behaviours, for people with both conditions, it is best to treat the OCD first.

ADHD and Learning Difficulties

It’s estimated that up to 50% of all kids with ADHD have a learning disability or related condition. Learning difficulties that are comorbid with ADHD such as dyslexia, dysgraphia, dyscalculia and dyspraxia may not become apparent until ADHD is under control. A child who is receiving treatment for ADHD symptoms may still underachieve academically if they have an unidentified learning difficulty.

ADHD and Autism

It’s common for there to be a degree of overlap between ADHD and autism  – also known as ASD (Autistic Spectrum Disorder) or ASC (Autistic Spectrum Condition). It’s estimated that nearly one third of Autistic children also meet the diagnostic criteria for ADHD and there are some shared behavioural characteristics. However, ADHD and autism are quite different and shouldn’t be considered in the same way so as to avoid misdiagnosis and ineffective treatments. It’s important to have an accurate diagnosis by a qualified specialist for Autism and/or ADHD.

As with ADHD, autism is being increasingly recognised and more adults are coming forward for assessment. An adult ASD/ASC diagnosis allows a person to move on with their life in a way that is right for them, as well as providing a great sense of relief and understanding. The ADHD Centre is now offering private adult autism assessments.

ADHD and Sleeping Disorders

Both adults and children with ADHD often have difficulties falling asleep, staying asleep and not waking up at the desired time. It’s estimated that three out of four children and four out of five adults with ADHD experience some form of sleep disorderExperts often check sleep problems when they’re diagnosing ADHD. Lack of sleep can make symptoms of ADHD worse and poor sleep may become a repetitive cycle that is hard to break. Our blog about Coronasomnia and ADHD offers some helpful tips for people with ADHD to improve their sleep hygiene. 


Comorbid conditions of ADHD can make diagnosis difficult as one condition may appear more prevalent than another. When someone struggles with more than one condition, the symptoms of each become more intense. It’s crucial to make distinctions between different conditions and if treatment isn’t successful for all symptoms to consider other causes too. It’s easy to miss certain conditions when they are combined with others. This is why it’s so important for a diagnosis to be made by a qualified professional with experience in identifying comorbid conditions.


When it comes to treatments, we must remember that ADHD and comorbid conditions affect people in different ways; ADHD symptoms are part of a wide spectrum of conditions with varying degrees of severity. Treating symptoms of one condition may cause another one to worsen and a certain amount of trial and error over time may be required to find the most effective treatment combination option. We must also consider that people change and develop over time; this can be especially rapid in children so regular reviews are needed to stay on top of physical and mental development as people grow up and grow older.

At the ADHD Centre, we provide a holistic service for both diagnosis and treatment for comorbid conditions along with ADHD.

Please contact us if you would like to find out more about booking a private assessment for ADHD or autism. You can reach us on 0800 061 4276  or by email at

Further reading

Your child’s ADHD is an iceberg

Symptoms – obsessive compulsive disorder

When it’s not just ADHD: symptoms of comorbid conditions

Social Anxiety Disorder and ADHD

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The ADHD Centre

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We have been diagnosing and treating people with ADHD since 2009.

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