Concerns regarding obsessive-compulsive disorder and attention-deficit/hyperactivity disorder, as well as comparisons of OCD vs. ADHD, can at times arise during mental healthcare assessments. Physicians looking to provide their patients with the best possible care, which entails understanding what condition they might be suffering from. Questions of comorbidity (co-occurring disorders) may also become relevant, making such analogies even more important as part of a comprehensive mental health assessment process. Read on to learn more about how OCD and ADHD can relate to one another.


OCD: Obsessing Amongst Oneself

Obsessive-compulsive disorder is universally defined as a mental health disorder based on obsessive thought content and compulsive reactions to it. OCD-related obsessions tend to be aversive, unpleasant, and intrusive, assailing the individual experiencing them with unwanted thoughts about a subject they would rather avoid.

The four most common OCD-related obsessions are:

  • Cleanliness and contamination.
  • Checking, organization, counting, and “just right” thinking.
  • Catastrophizing that a tragic event will occur to oneself or a loved one.
  • Taboo thoughts, typically over committing an act that is morally reprehensible, socially unacceptable, or that goes against one’s religion.

OCD-related compulsions can appear in the form of behavior or thought patterns, and often arise as a way to soothe away the troubling thoughts of their condition. They tend to take on a ritualistic pattern of reaction that repeats itself when an obsessive thought is brought to the fore of their consciousness.

Examples of OCD-related compulsions are numerous, and can include anything from opening and closing one’s refrigerator a specific number of times, to silently counting all the presidents of one’s country in chronological order, to snapping one’s fingers while saying “not today”…; the possibilities (and individual creativity) really are limitless.

While initially such rituals manage to assuage the disagreeable feeling caused by an OCD-related obsessive thought, eventually they lose their potency, and are instead incorporated into the very pattern of OCD actions that they were meant to alleviate. At this point, such reactions become OCD-related compulsions, with the individual feeling compelled to perform them, otherwise they will be overwhelmed by the unpleasantness they have come to expect from their condition.

Unlike the above, generally agreed upon OCD symptoms, theorists and researchers continue to debate about the underlying emotional theme at the heart of OCD. For decades, the American Psychiatric Association (APA) has defined OCD as an anxiety-based mental health disorder. Viewed as a maladaptive survival mechanism that maintains a state of hyperarousal in an attempt to prepare for a fearful, potential threat, the OCD-as-anxiety theory posits that OCD themes such as contamination or catastrophe are actually derived from primitive forms of self-defense: ensuring good hygiene, for example, could protect oneself from a life-threatening illness. The problem with OCD, as this theory suggests, is that such heightened awareness has been kicked into overdrive, causing the individual a great deal of anxiety, as well as to avoid many situations that do not pose them any real threat.

Opposing the APA’s position regarding OCD, more recent studies have presented the disorder as the result of induced distress, and not anxiety. Distress is defined as a relentless sense of uneasiness, combined with an inability to return to a state of calm. While anxiety is considered an acute fear like reaction, distress is seen as more of an unsettling, nagging disquiet. Under the “OCD-as-distress” theory, OCD obsessions are considered pervasive and unsettling thought content, and not the mark of some earlier, primal fear, or dying from an illness.

Regardless of its central source of disquiet, OCD is seen as a very serious condition. 2.3% of US adults and 1%-2.3% of US children and adolescents contend with an official OCD diagnosis. Though the disorder can appear at any age, its symptoms usually become apparent between age ten and early adulthood. Due to OCD often being misdiagnosed as simply eccentricity, patients usually only begin receiving treatment between the ages of 14-17.

According to the APA, adult females develop OCD at a slightly higher prevalence than adult males, and boys develop OCD at a slightly higher prevalence than girls.

OCD and ADHD - Where They Differ and Converge

ADHD: Impulsive External Reactions

The APA defines attention-deficit/hyperactivity disorder through three main factors: distractibility, hyperactivity, and impulsivity. It is also linked to developmental difficulties, as the distractibility and impulsivity connected with ADHD often hinders the (young) individual facing this condition from reaching certain developmental milestones.

ADHD-related distractibility is manifested through a difficulty in focusing one’s attention on the task at hand, a constantly wandering mind and disorganization, all of them not due to a lack of comprehension.

ADHD-related hyperactivity refers to excessive, inappropriate motor activity, such as fidgeting, talking, or general restlessness. Such activities can eventually wear out those around the individual exhibiting hyperactivity.

ADHD-related impulsivity is defined as spur-of-the-moment, potentially harmful actions that are carried out without much forethought. Impulsivity is often related to difficulties with delayed gratification, and can manifest through social intrusiveness, such as constantly interrupting others, or decision-making that fails to consider its long-term effects.

ADHD is twice as prevalent among children as it is among adults: 5% of children are diagnosed with this condition, compared to 2.5% of adults. ADHD symptoms are often observed early in life, when the individual is a toddler, but are hard to distinguish from normal, age-appropriate behavior before the age of four.

ADHD appears differently at different developmental stages:

  • During preschool, hyperactivity is the most prevalent symptom.
  • During elementary school, inattention becomes the most prevalent symptom.
  • During adolescence, restlessness and impatience become the most prevalent symptoms.
  • During adulthood, inattention, impulsivity, and restlessness all become more prevalent.

ADHD is more common among males, with a 2:1 ratio in children, and a 1.6:1 ratio in adults. It is associated with poorer school performance, poorer job performance, and greater interpersonal conflict.

OCD and ADHD: Where They Differ and Converge

Generally speaking, the differences between OCD and ADHD outnumber their shared characteristics. OCD is an anxiety (or distress)-based disorder that creates a great deal of adverse mental stimuli, causing the individual experiencing it to feel trapped within their own internal obsessions. ADHD, on the other hand, revolves around problems with focus and controlling one’s impulses to react externally, often creating a great deal of friction on an interpersonal level. Finally, the repetitiveness of OCD-related compulsions seems to stand in opposition to the seemingly random impulsive behavior exhibited by individuals with ADHD.

And yet, despite their distinctions, OCD and ADHD do share certain commonalities. Firstly, both disorders have been linked to abnormal neural activity of the frontostriatal system, a high-order system responsible for motor, cognitive, and behavioral activity. The type of abnormal activity, though, is quite different: those with OCD exhibit significantly higher levels of activity in this system, while those with ADHD exhibit significantly lower levels of activity in it.

Secondly, despite their opposite patterns of activity, both OCD and ADHD hinder executive functions, particularly response inhibition, decision-making planning, task switching, and working memory.

Thirdly, a certain level of comorbidity has been found, linking the two together: specifically, 21% of children and 8.5% of adults with OCD have been found to also contend with ADHD.

Attempting to explain these results, a current theory suggests that OCD overflows the frontostriatal system with information, as the individual continues doubting themselves and repeatedly checking if they had been wrong in their thoughts or actions. Someone with ADHD, on the other hand, would suffer from the disorder’s characteristic impulsivity and inattention, causing a similar pattern of decreased executive functioning.

Receiving Professional Support

Whether differing or alike, both OCD and ADHD are considered serious mental health disorders that can severely impact one’s quality of life. Early diagnosis, assessing symptom severity and providing proper treatment are key elements in recovery for both these conditions, making the case for consultation with a licensed mental health professional.