Attention deficit hyperactivity disorder (ADHD) is a common mental health condition, affecting around 1 in 10 children and 1 in 20 adults. According to the fifth edition of the diagnostic and statistical manual of mental disorders (DSM-V), ADHD is characterized by “a persistent pattern of inattention or hyperactivity-impulsivity that interferes with functioning or development.” For example, a child with ADHD may struggle to pay attention to details, follow instructions, or sit still in situations where moving around would be inappropriate to such a severe degree that they’re unable to complete tasks at school or develop normal social relationships.
Obsessive-compulsive disorder is defined by the presence of unwanted images, thoughts, beliefs, feelings, and urges that cause distress or anxiety (called obsessions), as well as physical behaviors or mental actions carried out in an attempt to relieve this distress or avoid unwanted outcomes (called compulsions).
At first glance, these two disorders may not appear to share anything notable in common. We spoke with Dr. Patrick McGrath, psychologist and Chief Clinical Officer at NOCD, for a more nuanced take on OCD and ADHD, how they are related, whether you can have both, what the treatments are, and more.
How Are OCD and ADHD Related?
Though OCD and ADHD are significantly different disorders, they overlap in surprising ways when it comes to their symptoms and underlying biological causes. Here are some of the ways they are similar and distinct.
Symptoms
Does OCD Involve Inattentiveness?
ADHD is partly defined by difficulties with attention and executive function (e.g., issues with working memory, task shifting, and time management). Interestingly, people with OCD can experience similar problems. A recent meta-analysis, or study of studies, found that individuals with OCD often have impairments with multiple types of executive function. This may explain some OCD symptoms, such as getting stuck on unpleasant thoughts. Impaired executive functioning could also be a symptom of OCD. Being severely distracted by intrusive, upsetting thoughts, images, and urges can make it difficult to pay attention to anything else, interfering with your daily functioning.
Does OCD Involve Impulsivity?
Though both conditions can involve difficulties or impairments with attention and executive function, recent studies have found that risk-taking and impulsivity are not features of OCD.
Does ADHD Involve Intrusive Thoughts or Compulsions?
Generally speaking, ADHD does not involve obsessions or compulsions. However, as Dr. McGrath notes, it can appear that way. For example, though ADHD is associated with distractibility, researchers have found that people with the condition can become “hyperfocused” on particular tasks or topics. However, this type of “obsession” is entirely distinct from the kind associated with OCD. This is because individuals with ADHD generally do not experience intrusive or unwanted thoughts, images, and urges, though they can, especially if they also have OCD (elaborated below).
Similar things are true regarding compulsions. Individuals with ADHD may engage in behaviors that appear to be similar to compulsions, but are quite distinct. For example, a child who is easily distracted may spend an excessive amount of time ordering, arranging, and cleaning things. But while these may appear similar to certain behaviors in people with OCD, they aren’t compulsions, as they aren’t done to alleviate anxiety associated with obsessions or to prevent a bad outcome.
Underlying Biology
Evidence suggests that both OCD and ADHD are partly caused by dysfunction in the same brain regions and systems. Specifically, they are correlated with abnormal activity of the frontostriatal system, a part of the brain involved in executive functions such as short-term memory, planning, and behavioral control.
Interestingly, though both conditions are associated with dysfunction in the same regions, their characteristic abnormalities are opposite: while ADHD is correlated with decreased activity in this part of the brain, OCD is associated with overactivity.
Zooming in from brain regions to neurotransmitters (chemical messengers in the brain), we can see that both disorders are associated with imbalances in neurotransmitter levels. However, while OCD is correlated with low serotonin levels, ADHD is connected to dopamine dysfunction. This has important implications for which medications are best used to treat each condition, which we return to below.
How Can I Tell if I Have OCD or ADHD?
Here are four questions you can use to assess whether you’re experiencing OCD or ADHD.
#1: Do I Experience Intrusive Thoughts?
Though anyone can experience an unwanted thought from time to time, obsessions are not a distinguishing feature of ADHD. So, if you often experience intrusive thoughts, images, or urges, you’re more likely to have OCD.
#2: Do I Perform Compulsions?
Since individuals with ADHD don’t experience compulsions as people with OCD do, if you don’t find yourself performing mental or physical actions in order to rid yourself of anxiety and uncertainty or to prevent an unwanted outcome, that means you probably don’t have OCD.
#3: Am I Impulsive or a Risk-Taker?
By and large, individuals with OCD tend to be fairly cautious and opposed to taking risks. This contrasts with ADHD, which is often characterized by impulsivity and risk-taking behaviors.
#4 Have Stimulants Caused More Intrusive Thoughts?
If a patient is having trouble with attention and executive control, they may be prescribed a category of medications called stimulants. While these help people with ADHD, they are generally bad for people with OCD and anxiety disorders. If you’ve been prescribed a stimulant and it made you obsess and ruminate more, that could be evidence that you have OCD.
Misdiagnoses
Despite the differences in impulsivity and risk-taking tendencies, misdiagnoses can occur.
Can OCD Be Misdiagnosed as ADHD?
Experts suggest that OCD can frequently be misdiagnosed as ADHD. The reason is that people with OCD often experience difficulties with attention and executive functioning. “It can appear as if they’re not paying attention in school when the reality is they’re doing all sorts of stuff involving obsessions and compulsions in their head,” shares Dr. McGrath. “And because of that, they might look like they have ADHD when that’s not actually the case.”
Can ADHD Be Misdiagnosed as OCD?
It’s possible for ADHD to be misdiagnosed as OCD, but it’s probably less common. Since the presence of obsessions and compulsions defines OCD and individuals with ADHD typically do not display either, a misdiagnosis of ADHD as OCD is unlikely.
Can You Have Both OCD and ADHD?
Yes, it is possible to have both conditions. Estimates suggest that up to 30 percent of children and adolescents with OCD also have ADHD.
However, some argue that a genuine combined diagnosis is actually much less common. This is because, as noted above, individuals with OCD rarely exhibit impulsivity or risk-taking behavior. Also, because ADHD and OCD are associated with opposite activity in certain parts of the brain, some feel that it’s unlikely for a person to have both.
In either case, many individuals show sufficient symptoms of both conditions to be diagnosed with both OCD and ADHD.
Does ADHD Make OCD Worse?
ADHD can exacerbate the symptoms of OCD. For example, one study found that compared to adults with OCD alone, those additionally diagnosed with ADHD engaged in more obsessions and compulsions. The authors hypothesize that the additional impairments in executive control caused by ADHD may make it harder for individuals with both disorders to resist compulsions that make OCD worse.
In addition to increasing the frequency of obsessions and compulsions overall, the combination of disorders may make some intrusive thoughts and OCD subtypes more common. In the study referenced above, the researchers found that obsessions and compulsions related to hoarding, symmetry, and order were more common among those with both conditions.
Can OCD and ADHD Be Treated at the Same Time?
OCD and ADHD can both be effectively treated at the same time through some combination of therapy and medication.
Therapy
Exposure and response prevention (ERP) is the most popular and effective treatment for OCD. For this treatment, individuals with OCD are exposed to some stimulus that triggers an obsession (e.g., a fear of health contamination) without engaging in compulsions in response (e.g., seeking reassurance through internet searches or doctors). Over time, preventing compulsions in response to obsessions and anxiety allows people with OCD to habituate to uncertainty and distress, while reducing the strength of the compulsive urges.
ADHD can also be managed with ERP, but it’s often combined with other behavioral therapies. For example, therapists may additionally employ parenting training, goal-setting strategies, and lifestyle skills training. In general, it benefits from a more holistic approach that draws from several therapeutic techniques.
Medication
ADHD is often treated with a class of medications known as stimulants, such as methylphenidate or dextroamphetamine-amphetamine, which increase the amount of dopamine, a chemical messenger involved in motivation and reward learning. However, as Dr. McGrath highlights, they shouldn’t be used to treat people with both conditions: “You don’t give people with OCD a stimulant medication.” This is because it can intensify their anxiety and magnify their symptoms.
Fortunately, there are also several non-stimulant medications for ADHD. Some examples include
- Atomoxetine
- Clonidine
- Guanfacine
- Viloxazine
These medications work on different chemical responses in the brain to avoid the possible anxiety-inducing effects of traditional stimulants.
OCD is typically treated with selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine or sertraline, which impact serotonin, a chemical messenger believed to play a role in anxiety-related disorders. These medications may be combined with the non-stimulant alternatives listed above to treat patients with both OCD and ADHD.
