How OCD and ADHD Similarities Can Cause Misdiagnosis

Obsessive-compulsive disorder (OCD) and attention deficit hyperactivity disorder (ADHD) are distinct conditions, but they do share some similar symptoms and may even occur together at the same time. This can create complications when it comes to diagnosis and treatment.

OCD and ADHD affect similar regions of the brain and have effects on functioning and relationships. Both OCD and ADHD can make it challenging for people to pay attention, which can interfere with a person's ability to function in areas such as work and school. 

However, there are important differences that help distinguish the two conditions. For example, while people with ADHD often struggle with impulsivity, those with OCD tend to overthink and avoid risk-taking.

Overview of OCD and ADHD

OCD is a mental health condition characterized by obsessions (recurring, intrusive thoughts) and compulsions (repeated behaviors). OCD is believed to affect 1 in 100 adults and 1 in 200 children, according to the International OCD Foundation (IOCDF). The Anxiety and Depression Association of America (ADAA) reports the median age of onset is 19, with one-fourth of cases present by age 14. One-third of adults with OCD had the disorder as a child. 

ADHD is a form of neurodivergence characterized by hyperactivity, impulsivity, and inattention. ADHD is estimated to affect between 5-9% of the population, whereas OCD affects about 1-2%.

It is pretty common knowledge that OCD coexists with several other disorders, including other anxiety disorders and major depressive disorder (MDD). Many also recognize there are crossover symptoms of OCD-like behavior and several other disorders.

Autism spectrum disorders and ADHD are among those. Some research also suggests that there is an overlap of ADHD and OCD among people who engage in hoarding behaviors.

Similarities Between OCD and ADHD

To understand how OCD and ADHD are sometimes misdiagnosed, it can be helpful to look at the similarities between the two conditions. While they seem very different, the overlapping symptoms and effects can create challenges.

• Regions of the brain affected: Both conditions are associated with abnormalities in the neural pathways in the brain's frontal lobe.
• Attention issues: People with ADHD often struggle to pay attention and stay on task. Those with OCD may have similar challenges because they are distracted by their obsessions and compulsions.
• Disruptions in school and work: Both conditions make it difficult for people to stay on task, which affects their ability to perform in these settings.
• Relationship disruptions: OCD and ADHD can create challenges in relationships. Impulsivity, attention problems, and other disruptive behaviors can interfere with social functioning. Obsessions and compulsions can also present challenges when it comes to maintaining relationships.
• Risks for other conditions: OCD and ADHD also increase a person's risk of having other conditions, including depression, GI disorders, and sleep disturbances.

Key Differences Between OCD and ADHD

While there are some similarities between the two conditions, there are also important differences that help tell them apart.

• Risk tolerance: People with ADHD are more likely to engage in impulsive, risk-taking behaviors, while those with OCD tend to avoid risks.
• Interactions: ADHD typically leads to more externalizing behavior (directing behaviors outward), while OCD leads to more internalizing behavior (directing behaviors inward).
• Changes over time: While both conditions are lifelong, ADHD traits may become less evident as people enter adulthood, although research suggests that 80% of people will continue to have ADHD into adulthood. OCD symptoms may remain more consistent over time but become worse due to things like stress.

What Causes OCD and ADHD?

OCD and ADHD are strange bedfellows. Both are caused by problems in the frontal lobe. However, ADHD is associated with under-activity (not enough dopamine and norepinephrine) in the brain, and OCD is linked to overactivity (too much serotonin).

Although the different types of ADHD present very differently, all types are believed to be caused by low levels of dopamine and norepinephrine in the brain. The person with the hyperactive type of ADHD, who is fidgety, restless, impulsive, and careless, would appear to be the opposite of a person with OCD, who is generally more cautious, focused, and attentive.

People with the inattentive type of ADHD are often distracted, disorganized, daydreamy, and forgetful. Again, not your stereotypical OCD traits. Those who have the combined type of ADHD (about 70%) have symptoms of both.

OCD and ADHD Misdiagnosis

These two disorders often get confused when a child (or adult in a work setting) with OCD has trouble in school. After all, ADHD, which causes problems with executive functioning (organization, planning, reasoning, prioritizing, executing projects, following through with work, etc.), creates challenges in the classroom.

How OCD Can Mimic ADHD

Children with OCD who spend a lot of time ordering, arranging, or checking their books, supplies, and handwriting may appear to be having problems with executive functions when they are simply trying to get or keep things on the desk in the proper place. Understanding what motivates the child’s (or adult’s) behavior is key to a proper diagnosis.

How ADHD Can Mimic OCD

ADHD can result in OCD-like coping skills. A child or adult who has trouble getting organized or who is easily distracted may spend an inordinate amount of time arranging, ordering, and cleaning things. Sometimes, that is procrastination, a typical ADHD trait, but it may be an ADHD coping skill.

Many people with ADHD become over-stimulated by the clutter and disorganization in their environment. This often results in anxiety or simply shutting down. As a result, they may learn strategies to prevent clutter and disorganization that look like OCD behaviors, i.e. arranging, ordering, and checking.

Distinctions Between OCD and ADHD

With regard to proper diagnosis, it is important to remember that ADHD is present across all domains; OCD is generally very specific with regard to obsessive thoughts and compulsive behaviors. It is also worth noting that not all people with OCD have the type related to fear of germs and cleaning. In fact, most do not have spotless homes or lockers.

Although ADHD was once believed to affect only children, the research has finally caught up with reality; in 2013, the DSM-5 moved ADHD from the category of "Disorders Usually Diagnosed in Infancy, Childhood, or Adolescence" to that of "Neurodevelopmental Disorder" recognizing that many continue to have symptoms into adulthood.

It was once believed to largely disappear after puberty. Today, experts recognize that while ADHD characteristics change as people age, it is a lifelong form of neurodivergence.

Treatment for OCD and ADHD

About 30% of people with ADHD have co-occurring anxiety disorders, including OCD. Those who have problems with low dopamine and/or norepinephrine and high levels of serotonin may indeed have both OCD and ADHD. In these cases, it is extremely important to treat both disorders. However, doing so requires skill and patience.

Prescribers often treat the symptoms that are causing the most problems first. When both conditions are present, researchers recommend treating OCD first before addressing ADHD.

The treatment for OCD with selective-serotonin reuptake inhibitors (SSRIs) is not usually contraindicated in ADHD, and some estimate up to 50% of people with ADHD also have depression).

However, stimulant medications used to treat ADHD can exacerbate OCD symptoms with very serious outcomes. This includes the worsening of OCD symptoms. For those with both disorders, there are non-stimulant medications for ADHD that may have less impact on OCD symptoms.

Keep in Mind

While it isn't common for OCD and ADHD to occur together, it can happen. The two conditions also share some overlapping characteristics, which can sometimes make diagnosis more challenging. If you suspect you have OCD, ADHD, or both, talk to your doctor for further evaluation. Your healthcare provider can assess your symptoms, make a diagnosis, and recommend treatments that can help.