The Characteristics And Interrelationship Between OCD And ADHD

Here's a look at how OCD and ADHD can occur together, along with how to differentiate the disorders.

Have you considered clinical trials for Obsessive compulsive disorder (OCD)?

We make it easy for you to participate in a clinical trial for Obsessive compulsive disorder (OCD), and get access to the latest treatments not yet widely available - and be a part of finding a cure.

What is OCD?

OCD is a condition characterized by compulsions or obsessions. These may include inappropriate, intrusive impulses, recurrent images, and persistent thoughts causing distress and anxiety to the individual.

A person with OCD uses their compulsions to calm their obsessive thoughts. When untreated, OCD can lead to depression, anxiety, and other mental health disorders.

While most people experience compulsions and obsessions, the diagnostic criteria cite "obsessions, compulsions, or both," implying an individual could present with only one of these symptoms or both to meet the criteria for OCD. 

Though less common than ADHD, approximately 2.3% of the American population has experienced OCD at some point in their lifetime.¹

Symptoms of OCD

Obsessions are unwanted, upsetting, and repetitive thoughts, including:

  • Profound need to make things predictable, symmetrical, or orderly

  • Unwelcomed religious or sexual thoughts

  • Thoughts of harming someone else or self-harm

  • Intense fear of contamination or acquiring infections

Some individuals feel compelled to perform specific actions to relieve the anxiety resulting from these thoughts. Compulsive behaviors may include:

  • Regular checking or re-checking

  • Precise arranging or organizing of objects

  • Counting rituals

  • Excessive or extreme cleaning

The things that cause OCD-related fears and how a person responds to these triggers are highly individualized. However, compulsions and obsessions are time-consuming, creating conflicts in several areas of life.

What is ADHD?

Attention deficit hyperactivity disorder (ADHD) is a developmental illness that causes people to be extremely active, impulsive, and/or inattentive — and in some situations, all three symptoms will occur simultaneously.

People with ADHD struggle to maintain order in their lives and often do not complete tasks from start to finish. The illness can produce difficulties at home, the workplace, or school.

In the United States, around 6.1 million children have been diagnosed with ADHD.²

One of the most frequent forms of documented neurodevelopmental problems in the United States is attention deficit hyperactivity disorder, which according to another study, affects approximately 9.4% of the country's youth.³

Symptoms of ADHD

ADHD symptoms start before 12 years of age, while the diagnosis may persist for many years later, often into adulthood. Symptoms also vary in severity and between individuals.

Some people struggle to remain attentive, while others are more hyperactive and impulsive. A high%age of the population will experience a combination of the following symptoms:

  • Fidgetiness

  • Heightened need to be up and moving

  • Forgetfulness and distractibility

  • Trouble completing complex projects from start to finish

  • Appearing like the person is not listening during a conversation

  • Problems staying organized and losing belongings frequently

  • Difficulty staying on track and focusing

  • Impulsivity

  • Excessive talking

  • Propensity to interrupt other people

Distinguishing between ADHD and OCD is critical to understanding how these disorders may affect a person's quality of life and implementing the right treatment.


Imaging studies examining brain activity indicate similarities between OCD and ADHD. Both conditions produce atypical activity in the brain's frontostriatal area. This section regulates cognitive and executive functions, as well as behavioral and motor capacities.

The regions in the brain involved in planning, organizing, executing, and controlling impulses and sustaining attention indicate "atypical activity" in people with OCD and ADHD. This implies that the way this brain region communicates with other areas of the brain is unusual or uncommon among individuals with these disorders, and there are shared characteristics between the two conditions.

A dysfunctional frontostriatal circuit affects a person's ability to plan and remember things. For example, it may impact your decision-making abilities or self-control.

OCD and ADHD present similar functions: planning, impulse control, and attention. Although both conditions differ, you can have both.


ADHD and OCD stem from dysfunction in the brain's frontal lobe, but OCD occurs due to over-activity (overproduction of serotonin). In contrast, ADHD results from under-activity (low norepinephrine and dopamine) in the brain.

While different forms of ADHD present varying symptoms, all forms of the condition stem from low levels of norepinephrine and dopamine in the brain. A person with hyperactive ADHD, characterized by being careless, impulsive, restless, and fidgety, is the opposite of someone with OCD, which is more attentive, focused, and cautious.

People with inattentive ADHD are forgetful, daydreamy, disorganized, and distracted. These are not stereotypical OCD traits. Those with the combined form of ADHD (approximately 70% of the population) have symptoms of both.


The confusion between the two arises when a child or an adult with OCD experiences challenges in school. The prevailing belief is that ADHD, which impairs cognitive functioning (following through with work, executing projects, prioritizing, reasoning, planning, organization, etc.), causes havoc in the classroom.

A child with OCD who takes extra time to arrange, check or order their handwriting, supplies, and books may appear to have issues with executive functions. Instead, they could be simply trying to maintain items in appropriate places. Understanding what motivates an adult's or child's behavior is essential to ensure a proper diagnosis.

ADHD causes OCD-like coping techniques. A person who is easily distracted and has challenges staying organized may spend extra time cleaning, ordering, and arranging things. Sometimes, a typical ADHD trait such as procrastination may also be a coping skill.

Most people with ADHD are over-stimulated by disorganization and the clutter in their surroundings. This may induce anxiety or make them shut down. They learn approaches to prevent disorganization and clutter, which may appear like OCD symptoms — checking, ordering, and arranging.

In terms of diagnosis, ADHD is present across a broad spectrum of symptoms; OCD is relatively specific regarding compulsive behaviors and obsessive thoughts. Not all individuals with OCD have the form associated with cleaning and fear of germs. Most of these people do not have spotless lockers, desks, or homes.

In the past, there was a misconception that ADHD only affected children. The current DSM-5 criteria transferred ADHD from "Disorders Usually Diagnosed in Infancy, Childhood, or Adolescence" to "Neurodevelopmental Disorder," acknowledging that some symptoms continue into adulthood.

Co-occurrence of ADHD and OCD

Can you have OCD and ADHD at the same time? Maybe. This is called comorbidity. Some researchers who have investigated the biological and neurological connection between the conditions cite that between 8% and 25.5% of children with ADHD or OCD have dual diagnoses. For instance, one study found an 11.8% ADHD prevalence in people with OCD, while two other studies of children with OCD found that 17.1% and 25.5% had comorbid ADHD.⁴ ⁵ ⁶ ⁷

However, other researchers believe having the two is highly unlikely and rare. These experts believe that the dual diagnosis rates may be inflated due to the overlapping symptoms of the disorders.⁸

They provide that OCD may result in "executive function overload," whose symptoms appear like those caused by ADHD. There is no research implying that one disorder can cause the other. However, one 2019 study supports that some people with ADHD are misdiagnosed with OCD.

It is challenging to establish the exact co-occurrence rates. Some systematic reviews provide that the estimated comorbidity levels are mostly inconsistent across the literature.⁹

Research from 2016 indicates that adults with OCD and ADHD have an earlier onset of OCD symptoms. They depict specific traits earlier than people without ADHD.¹⁰

A separate study involving children diagnosed with both disorders received treatment for OCD. As their OCD traits subsided, their impulsivity, hyperactivity, and inattention decreased. The researchers concluded that OCD potentially caused ADHD-like symptoms. Among children with ADHD and OCD, if ADHD is left untreated, it can adversely affect OCD treatment.


ADHD is treated using a combination of behavioral therapies, parental training, and medication. On the other hand, OCD therapy combines brain stimulation and cognitive behavioral therapy, habit reversal training, exposure therapy, and medication.

It is essential to understand your diagnosis to ensure that you are on the proper medications. This will also improve the quality of treatment outcomes. The medications used in each case differ. For instance, methylphenidate, prescribed for ADHD, can cause OCD symptoms in some cases.

People with ADHD may experience alleviated symptoms as they grow older, especially if they are on treatment. However, the condition may persist through adulthood. Approximately half the population diagnosed with ADHD as children will not experience the same symptoms as adults.

OCD comes and goes throughout a person's lifetime. Research has found that 40% of treated children diagnosed with OCD during childhood will go into remission by the time they reach adulthood.¹¹

The lowdown

ADHD and OCD have overlapping symptoms, such as inattention, which may cause issues at work or school. They are associated with GI problems, sleep issues, depression, anger, and anxiety.

While some people receive a dual diagnosis, it is more likely that OCD will result in ADHD-like symptoms. Healthcare practitioners employ similar psychotherapy techniques to manage both disorders, but treatment with medications differs.

If you suspect you have OCD, ADHD, or both, see a mental health professional specializing in either condition. They will walk you through the next steps for your specific case.

  1. Obsessive-compulsive disorder (OCD) | NIH: National Institute of Mental Health

  2. National prevalence of ADHD and treatment: Information on children and adolescents, 2016 | Centers for Disease Control and Prevention (CDC)

  3. Attention-deficit/hyperactivity disorder: diagnostic criteria, epidemiology, risk factors and evaluation in youth (2020)

  4. The neurobiological link between OCD and ADHD (2014)

  5. ADHD prevalence and association with hoarding behaviors in childhood-onset OCD (2011)

  6. A naturalistic exploratory study of the impact of demographic, phenotypic and comorbid features in pediatric obsessive-compulsive disorder | Karger

  7. Comorbidity of obsessive-compulsive disorder and attention-deficit/hyperactivity disorder in referred children and adolescents (2006)

  8. Comorbidity between attention deficit/hyperactivity disorder and obsessive-compulsive disorder across the lifespan: A systematic and critical review (2015)

  9. Comorbidity between attention deficit/hyperactivity disorder and obsessive-compulsive disorder across the lifespan: A systematic and critical review (2015)

  10. The clinical characteristics of ADHD and obsessive-compulsive disorder comorbidity (2016)

  11. Predictors of early adult outcomes in pediatric-onset obsessive-compulsive disorder (2014)

Other sources:

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