The percentage of people with ADHD who also have OCD is high. When one disorder is present, it can be difficult to spot the other—and at times either may be misdiagnosed as the other or both are missed entirely.
The occurrence of OCD and ADHD is puzzling, as the two conditions seem to exist on opposite ends of a spectrum.The symptoms of these conditions are so similar that they cannot always be distinguished.
Misdiagnosis or Overlooked Diagnosis?
Children with OCD are more likely to be misdiagnosed as having ADHD, than vice versa. This is because the two conditions can look similar and involve different types of symptoms (inattention versus repetitive behaviors).
Let's briefly review what we already know about ADHD and OCD before exploring the ways they overlap.
What Is ADHD? The Basics
ADHD is a neurological condition, meaning it manifests during the development of the brain and has strong genetic (hereditary components).
The parts of the brain that regulate emotions, attention, and focus are greatly affected by ADHD. Characterized by persistent inattention (difficulty focusing on tasks), hyperactivity (excessive fidgeting or restlessness) and impulsivity (the tendency to act without thinking first), ADHD is a neuro-biological disorder with symptoms often impairing functioning at school as well as home
The diagnostic criteria for ADHD include:
ADHD is defined by the presence of three core symptoms:
The symptoms must cause problems in at least two areas of a person’s life (for example, home and school or work and home).
ADHD manifests itself in a number of ways:
- Difficulty concentrating or focusing on a single task.
- The inability to keep track of material and or time
- Difficulty completing complex projects.
- Inattention and forgetfulnes
- Interrupting or talking over the person who is speaking
- Seeming to ignore the conversation at hand
- Increased restlessness
- Excessive talking
While ADHD is present since birth it can go undiagnosed often. People with ADHD may not be diagnosed until the demands of their lives exceed their capacity to meet them. And many people develop sophisticated compensatory strategies that mask areas of struggle—it might be years after they've developed successful work and social habits before anyone identifies an underlying attention problem.
How common is ADHD? (Prevalence)
ADHD is more common than OCD and one of the most prevalent mental disorders, affecting 5.2 % of children and adolescents across the globe (Polanczyk et al. 2007).
According to the Centers for Disease Control and Prevention (CDC), about 9.4% of U.S children have been diagnosed with ADHD, which is one of the most common developmental disorders in this country.
Let's repeat that: This is a developmental disorder and neurological (brain) disorder, not environmental or behavioral. Yes, it affects behavior – but that is not where it stems from.
OCD is the fourth most common psychiatric disorder (IN THE WORLD) affecting about 3% of people at some point in their lives. It usually begins during childhood or adolescence.
The symptoms of OCD usually first appear in childhood and reach their peak between ages 11 and 21. When people with OCD have other conditions, but ADHD is one of the most common ones. Reference: Brem et al., 2014.
The main features of obsessive-compulsive disorder include obsessions, or thoughts that recur and cause anxiety; and compulsions, or actions performed over and over in an attempt to neutralize the anxiety caused by the obsessions.
People with obsessions suffer from recurrent thoughts that produce anxiety, often leading them to perform compulsions (habits or rituals) in an attempt to reduce this stress.
In order for someone to be diagnosed with OCD, the thoughts must significantly interfere with their daily functioning.
Obsessive thoughts often focus on particular fears or worries, such as:
- A fear of being contaminated
SIDE NOTE: What does contaminated mean? Contaminate, taint, pollute, and defile mean to make impure or unclean. Contaminate implies intrusion of or contact with dirt or foulness from an outside source (logically enough, it derives from the Latin word tangere, meaning “to touch”). (Dictionary)
- Excessive worries that the lights or appliances may have been left on, and doors unlocked.Fear of acting in a way that will bring shame or humiliation upon oneselfDiscomfort with things not being in their proper place
- Sexual obsession or Sexually intrusive thoughtAnxiousness over health concerts and hypochondria
- Excessive religious concerns or feelings of guilt, shame, and impurity
People often experience compulsions like:
- Overzealous cleaning and excessive hand washing,Constantly checking of doors, locks, and appliances
- Rituals performed to prevent contact with unlucky or evil things.Moving and re-moving objectsUsing chants or sayings to think you will prevent bad things from happening. Hoarding things or collecting them obsessively in large quantities. (Source Brem et al., 2014).
The coexistence of OCD and ADHD (when they occur together)
I like to think of disorders as existing along a continuum rather than co-occurring. That we need to coexist with our mental health rather than see it as a negative occurring issue. Our mental health is something we need to align with and learn to live with as it is part of us, but not what defines us.Randi Owsley, LMSW
We need to learn how to live with mental health issues rather than see them as negative drawback that needs to be eliminated and eradicated.
You'll often hear therapists, psychiatrists and medical doctors mention co-occurence. This simple means 2 issues are happening together at the same time, and can often pair together (example: like peanut butter and jelly got together more often than not).
When medical professionals discuss co-occurence, they mean that two diseases or diagnosis' tend to show up together in people.
SIDE NOTE: What is Co-Occurrence? In other words, two things that happen together often enough to be noticed and make sense (like peanut butter and jelly) form a pattern.
Both ADHD and OCD are classified as neurodevelopment disorders that tend to begin in childhood, have a genetic component, and frequently occur together (aka co-occur).
It can be challenging to gain an accurate sense of how commonly they truly occur together. Below are summaries from several recent reports:
- About 8-25% of people with OCD also have ADHD. (Brem et al., 2014)A study involving people with OCD (age 4-82) found that those with ADHD were more likely to have hoarding disorder: 42% (Sheppard et al., 2010).A study of chilren with OCD in 2006 found that 25.5% had also been diagnosed with ADHD. Masi, 2006.
- The most common disorder diagnosed with OCD at an early age is ADHD (Brem et al., 2014)
Similarities between ADHD and OCD
The Impact of Work and School Difficulties
Both conditions can lead to problems in school and at work, negatively affecting grades, attendance and performance.
For ADHD, these problems can include a lack of awareness of time (we often called this “time blindness”; difficulty concentrating and focusing on tasks; and trouble organizing one's thoughts.
When a person has OCD, obsessions and compulsions can interfere with attention, focus, time management—and completing important tasks on time.
Sensory Issues (Processing Disorder or Sensitivity)
Sensory Processing Disorder (SPD) is a neurological disorder in which the brain has trouble processing information from one or more of the five senses: touch, taste, smell, sight and hearing.
Children with OCD tend to be over-sensitive and may react strongly to certain sounds, sights or other sensations.(Hazen et al., 2008). People with sensory processing sensitivities, particularly those who are overly sensitive to touch and sounds, may be more likely to develop symptoms of OCD later in life. (Dar et al. 2012).
Commonly, people with ADHD also often have problems modulating sensory input and can be either too sensitive or not sensitive enough to various stimuli, such as lights, textures or sounds.
The Impact of Intrusive Thoughts
People with ADHD and OCD often have intrusive thoughts as well (thoughts about bad things happening that may not actually be possible—for example, “What if I lose control and touch the person next to me?”).
Attention and Inattention, What is the Difference?
Both conditions impact a person’s ability to focus and pay attention, but it may appear that the individual is aloof or distracted only when he or she actually has trouble listening. This can impair work and academic performance.
People with ADHD have a hard time keeping their focus on one thing for a long period of time—especially when it's not something they're interested in.
The brains of people with ADHD are chronically under-stimulated, and so they seek out means to stimulate themselves.
Whereas, people with OCD may have trouble focusing for several reasons: They can become preoccupied with obsessions or feel compelled to complete rituals, which makes it difficult for them to pay attention; Or they experience severe anxiety whenever their attention is not focused on something specific—or when there's too much going on around them.
The person with OCD may become overwhelmed by his or her obsession, which leads to inattention.
Trichotillomania: Hair-Pulling and or Skin Picking
Although skin-picking and hair-pulling are typically associated with obsessive–compulsive disorder (OCD) or compulsive grooming, they may also occur in the context of attention deficit hyperactivity disorder (ADHD), usually during periods when people feel anxious.
Mood Disorders and Self-Injury
Both ADHD and OCD often occur together with anxiety and depression. Similarly, self-harm is associated both with impulsivity (ADHD) and compulsions (OCD).
Girl or women with ADHD are at elevated risk for self-harm, which is associated with difficulties regulating emotions and impulsive behavior.
Eating Disorders Linked to OCD and ADHD
Both groups have elevated rates of disordered eating and eating disorders, with body dysmorphia commonly being linked to OCD
Read the study here: Milos et al., 2002.
Eating disorders affect many girls with ADHD. Biederman et al., 2007 found that women with ADHD were 3.6 times more likely to have an eating disorder than the general population, and 5.6 times as likely to suffer from bulimia
Sleep Issues Re: OCD and ADHD
People with OCD are more likely than others to have sleep disorders. Approximately 70% of people with OCD have trouble sleeping(Nordahl et al., 2018).
Sleep issues are common in people with ADHD—approximately 25-50% of those diagnosed have trouble falling asleep, staying asleep, or both.
Example of Sleep Issues:
- Sleep-disordered breathing (snoring / sleep apnea).
- Circadian rhythm sleep disorders (like advanced and delayed sleep phase syndrome)
- Restless leg syndrome (Source: Wajszilber et al., 2021)
Up to 70% of children with ADHD have sleep difficulties (Grünwald and Schlarb, 2017). Nightmares and insomnia are most common.
Gastrointestinal Problems (Stomach distress)
GI Issues Both ADHD and OCD are associated with GI issues. People who have both ADHD and OCD are more likely than others to suffer from irritable bowel syndrome aka IBS. (Kedem et al., 2020).
Why Are These Misdiagnosed So Often?
Poor understanding of the medical doctor, not properly trained in diagnosis. Overlapping traits and lack of mental health care.
A child with OCD is more likely to be misdiagnosed with ADHD than the other way round. Another potential problem is that both conditions may exist but one of them may go undetected.
How Does OCD look like ADHD?
The child or adult may appear not to listen and have difficulty following directions or completing tasks, causing him/her to look like he/she has ADHD – which could result in a misdiagnosis. In reality, their executive functioning is impaired by an overload of obsessive-intrusive thoughts which can mimic ADHD symptoms.