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ADHD Comorbidity: Exploring the Most Common Co-Occurring Conditions
Mental Health

ADHD Comorbidity: Exploring the Most Common Co-Occurring Conditions

Published: 01/12/2023

Written by: Creyos

Comorbidity is the co-occurrence of two or more disorders, and it’s very common among individuals diagnosed with attention deficit hyperactivity disorder (ADHD). According to a 2019 study, 60 to 90 percent of children with ADHD have at least one comorbid disorder, which may have lifelong effects.

Because ADHD presents differently among individuals, it’s challenging to diagnose. The presence of comorbid conditions only adds complexity to the diagnosis and treatment of ADHD. That’s why understanding what they are and how they present is key for optimal patient care.

Many things can factor into the development of ADHD comorbidities, including:

  • Genetics
  • Epigenetics
  • Chronic infections
  • Inflammation
  • Life stressors
  • Trauma
  • Childhood abuse

Given these realities, a holistic approach to patient care can help clinicians working with ADHD. Patients can benefit from early identification, clear diagnostic data, and education about navigating comorbid conditions. That way, they have multiple strategies and tools for wellbeing.

In this article, we’ll explore the comorbidity in ADHD, which conditions are most common, how they affect diagnosis, and tools that assist in clinical decision making.

Key Takeaways

  • Over 60% of people with ADHD have at least one comorbid condition, requiring both to be treated together
  • Comorbid conditions can complicate diagnosis and treatment of ADHD, so prompt identification is key
  • Treatment typically involves a combination of medication, psychotherapy, and multimodal approaches for optimal care

Defining Comorbidity

Comorbidity refers to two or more disorders existing simultaneously. For example, a person may experience symptoms of ADHD along with symptoms of another comorbid psychiatric disorder.

When left unaddressed, comorbidities can lead to worse health outcomes, more complex clinical management, and higher healthcare costs.

The process of diagnosing and treating ADHD effectively means identifying any existing comorbid psychiatric disorders, such as anxiety, depression, or a learning disability. Treating one condition won’t necessarily resolve the symptoms of the other. For instance, treating ADHD won’t make the depressive symptoms of comorbid depression disappear. Both conditions need to be treated together to provide the patient with the best care.

The Impact of Comorbid Conditions on ADHD

ADHD looks different from patient to patient. Additionally, comorbid conditions can lead to more severe symptoms and greater challenges in day-to-day life. By identifying these co-occurring disorders earlier, clinicians can tailor treatment and give patients tools for better wellbeing throughout their lives.

A person with ADHD may also have comorbid conditions such as:

  • Antisocial personality disorder
  • Anxiety disorders
  • Depression
  • Bipolar disorder
  • Mood disorders
  • Learning disabilities
  • Substance use disorders

While various reports cite different rates of comorbidity with ADHD, it’s generally agreed upon that clinicians working with ADHD populations—children, adolescents, and adults with ADHD—should have knowledge about comorbid conditions to get to the root of all of the patient’s symptoms.

ADHD Comorbidities: Autism Spectrum and Other Neurodevelopmental Conditions

ADHD often co-occurs with neurodevelopmental disorders such as autism spectrum disorder, learning disorders, and tic disorders. Read on for more information about the symptoms that may overlap or interact with ADHD symptoms.

Learn how SohoMD accurately diagnoses ADHD and distinguishes comorbidities using Creyos Health

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Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a neurodevelopmental condition. It presents in many ways and can affect: sensory processing, social communication, emotional regulation, and behavior. ASD usually appears in childhood and persists into adulthood.

Autism shares similarities with ADHD, including being a type of neurodiversity and sharing symptom expression. Some overlapping symptoms may include challenges with:

  • Social skills
  • Attention
  • Concentration

Assessments like the Adult ADHD Self-Report Scale (ASRS) and Autism Spectrum Quotient (AQ) Questionnaire can help clinicians distinguish between the two, and empower patients with information on how each of these present individually and together.

  • One study demonstrated that it was possible to discriminate between symptom profiles of ASD and ADHD in children.
  • Another study demonstrated that children and adolescents with combined ADHD and ASD have more severe symptoms across all domains and an additive severity of sleep-related difficulties in this group.

Learning Disorders

Learning disorders are a group of conditions that affect a person’s ability to understand, process, or remember information. These disorders can impact a person’s performance in school, work, and daily life.

Some common types of learning disorders include:

  • Dyslexia: Difficulty with reading, spelling, and writing
  • Dyscalculia: Difficulty with math concepts and calculations
  • Dysgraphia: Difficulty with handwriting and fine motor skills
  • Auditory processing disorder: Difficulty processing and understanding auditory information
  • Visual processing disorder: Difficulty processing and understanding visual information

It is estimated that 20-60% of individuals affected with ADHD also experience learning disorders. Addressing learning disabilities in children with ADHD is critical in order to support them in academic and daily life, and to help them reach their full potential.

A 2013 study showed that children with ADHD symptoms had significantly higher risk for reading, spelling, and math difficulties as measured by SDQ scores (Strengths and Difficulties Questionnaire).

Differences observed by gender:

  • Reading and spelling difficulties were generally higher in boys (14.1%) vs girls (8.7%)
  • For students with ADHD symptoms, girls were at higher risk for reading and spelling difficulties than boys.
  • Math difficulties were higher in boys with high SDQ scores and girls in both high and low SDQ score categories

Tic Disorders

Tic disorders are characterized by sudden, uncontrollable movements or sounds, known as tics. These disorders can affect both children and adults, and children with ADHD are more likely than unaffected children to have tics.

Signs of ADHD typically emerge before the onset of tics, making early detection beneficial. The presence of tic disorders in individuals with ADHD can impact their behavior and learning, as tics may cause emotional tension, distract from daily tasks, and interfere with academic performance.

ADHD Comorbidities: Internalizing Disorders

ADHD also frequently co-occurs with internalizing disorders such as depressive disorder, bipolar disorder, and anxiety disorders. Read on to learn more about how these present and which tools help with identifying these conditions.

Depressive Disorders

Depressive disorder, also known as major depressive disorder, is a mental health condition characterized by persistent feelings of sadness, hopelessness, and a lack of interest in activities.

“Because children and adults with ADHD struggle with focusing, organizing tasks, and feeling restless, they might experience sadness, guilt, irritability, low self-confidence and helplessness. In some cases, these symptoms can signal depression.”

Both ADHD and depression can cause issues with concentration, motivation, and mood. For those with ADHD and depression, monitoring for suicidal thoughts or behaviors is vital, as this could indicate a severe form of depression needing immediate intervention.

Testing for depression as a comorbid condition of ADHD can give patients a clearer understanding of themselves. Plus, healthcare professionals can aid individuals with ADHD and depression in leading happier, more fulfilling lives.

Bipolar Disorder

Bipolar disorder is a mental health condition characterized by extreme mood swings, including periods of mania (high energy and activity) and depression (low energy and sadness).

ADHD and comorbid bipolar disorder share some symptoms, such as impulsivity, irritability, hyperactivity, emotional dysregulation, sleep problems, and problems with maintaining attention.

  • Up to 20% of people with ADHD experience bipolar disorder comorbidity

With assessment of bipolar disorder and ADHD together, clinicians can assist individuals with ADHD and bipolar disorder in reaching optimal mental health and well-being.

Anxiety Disorders

Anxiety disorders are a group of mental health conditions characterized by excessive fear, worry, and nervousness. About half of adults with ADHD also have an anxiety disorder. While anxiety and ADHD can co-occur, having ADHD may also cause or exacerbate anxiety.

Symptoms of anxiety disorders can include:

  • Persistent worry
  • Feeling on edge
  • Chronic stress
  • Fatigue
  • Trouble sleeping

Treatment for both ADHD and anxiety disorders typically includes medication, therapy, or a combination of both.

ADHD Comorbidities: Externalizing Disorders

Externalizing disorders, such as conduct disorder and oppositional defiant disorder, are characterized by disruptive, hyperactive, and aggressive behaviors. These disorders often co-occur with ADHD, further complicating diagnosis and treatment.

ADHD, Conduct Disorder, and Oppositional Defiant Disorder

Conduct disorder (CD) can be characterized by persistent aggression toward others and a pattern of rule-breaking behavior. Oppositional defiant disorder (ODD) is marked by ongoing defiance and anger-driven disobedience.

Diagnosing CD and ODD in children with ADHD involves a comprehensive evaluation, including:

  • Clinical interviews
  • Behavioral observations
  • Questionnaires for parents, teachers, caregivers, and the patient
  • Cognitive assessments

Accurate diagnosis along with ADHD is essential for supporting children with these disorders, to help them recognize their behavioral patterns, socialize more effectively, and better set and achieve their goals.

Diagnosing ADHD and Comorbid Conditions

Diagnosing ADHD and comorbid conditions can be challenging due to overlapping symptoms, but using tools that act as a diagnostic aid and strategies can help clinicians accurately identify and treat these conditions.

Diagnostic Tools and Strategies

Various diagnostic tools and strategies can help clinicians accurately diagnose ADHD and comorbid conditions. These tools include:

  • Clinical interviews
  • Detailed history-taking
  • Behavioral observation
  • Scientifically-validated scales

When it comes to getting objective data to measure indicators of ADHD comorbidities, assessments often include:

Using these diagnostic tools and strategies empowers healthcare professionals to better grasp the intricacies of ADHD and comorbid conditions, thereby facilitating more accurate diagnoses and the development of effective treatment plans.

How Creyos Can Help: Discover the ADHD Clinical Protocol and Report

With more patients self-diagnosing ADHD, based on symptoms they learn about online, there’s increased pressure on healthcare providers to offer clarity and accuracy around ADHD diagnosis and to disentangle comorbidities.

Psychiatrists have an opportunity to use objective measures to give patients clear answers about their cognition and an appropriate path for treatment or referrals. To meet the challenges of this rising demand, Creyos created a specific ADHD Clinical Protocol and Report, available right in the Creyos Health platform.

This report improves patient experiences and outcomes, while offering clinicians the confidence that comes with a protocol that is:

  • Scientifically validated
  • Built specifically to measure objective markers shown to be associated with ADHD
  • A set of objective measurements that complement subjective questionnaires
  • Effective for ongoing tracking of efficacy of medication and other treatment on cognition
  • Flexibly administered in clinic or at home


Learn more about the Creyos Health ADHD Protocol and Report

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Conclusion: A Complex and Prevalent Issue

ADHD comorbidity is a complex and prevalent issue that requires a comprehensive understanding of the various conditions that can co-occur with ADHD.

By recognizing the presence of comorbid conditions and employing a multimodal treatment approach that combines medication and psychotherapy, healthcare professionals can provide the best care and support for individuals with ADHD and comorbid conditions, helping them overcome their challenges and live fulfilling lives.

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