About Obsessive-Compulsive Disorder

by Leslie E. Packer, PhD
Last updated January 2009


Like many of the other disorders discussed on this web site, Obsessive-Compulsive Disorder (OCD) tends to run in families (Pauls, 2008), has been linked to neurological abnormalities in brain structure and function (Szeszko et al., 2004;  MacMaster et al., 2008; Geller, 2006). Like Tourette’s Syndrome, prenatal and perinatal factors may influence the severity and course of the disorder.

According to a recent study of rates of OCD in adults in the U.S., about 2.3% of all adults meet or met criteria for full-blown OCD at some point in their lives. During any one-year period, about 1.2% of adults meet diagnostic criteria (Ruscio et al. 2008, abstr.). OCD can have its onset in childhood, adolescence, or adulthood. Early-onset cases are more common in males. Early onset may also predict a more severe course, although gender and comorbid conditions also influence course, persistence of symptoms, and resistance to treatment [cf, de Mathis et al., 2008; Grados & Riddle, 2008; Walitza et al., 2008 (abstracts)].

OCD has two main elements to it: thoughts (obsessions) and behaviors (compulsions).


Obsessions are recurrent and persistent thoughts, impulses, or images that are experienced as unwanted, intrusive, and inappropriate. These thoughts usually cause marked anxiety or distress, and are not simply excessive worries about real-life problems.

The individual attempts to ignore or suppress the thoughts, images, or impulses, and/or tries to ‘neutralize’ them by some other thought or a specific action, although s/he realizes that the thoughts are the product of his or her own mind.

Certain themes tend to occur across all races, cultures, and societies. The following themes are some of the more common types of intrusive, repetitive thoughts:

  • Contamination fears (fear of germs, dirt, chemicals). This is one of the most common symptoms in terms of lifetime prevalence. Individuals may be morbidly afraid of getting AIDS or other infections, may be afraid to touch bathroom faucets, and may appear horribly anxious if anyone touches their food.
  • Doubting. Anyone can doubt whether they remembered to turn off the coffee pot or lock the door, but someone with OCD may repeatedly doubt themselves, even after checking. It is as if they don’t trust their memory: “Did I really do that or did I just think about doing it?”
  • Specific order or symmetry. Individuals with OCD may have a need to have things lined up or arranged in a particular way. The symmetry is also known as “evening up.”
  • “Just so” feelings or “just right.” Individuals with OCD may need to have things “perfect” or “just right.”
  • Aggressive or horrific imagery. Individuals with OCD may have intrusive thoughts that harm will come to a family member or others or themselves.
  • Sexual or “taboo” imagery. Individuals with OCD may be burdened with recurring thoughts of socially unacceptable behavior.
  • Moral and religious themes or “scrupulosity.”

If a child or an adult spends eight hours each day “stuck” on some thought but s/he doesn’t experience it as anxiety-producing or distressing and makes no attempt to stop the thoughts, then many professionals would argue that it does not meet the definition of obsessing and would not diagnose the child as having a disorder. Family members who have to live with someone who spends hours every day stuck on a thought generally have no doubt that they consider it a disorder, but it is important to note that not all that is “stuck” is obsessive thinking or obsessive worrying. There are other types of problems that can result in a child or adult being “stuck.” A mental health professional who knows these disorders can make a differential diagnosis.


Compulsions are repetitive behaviors or mental acts that the person feels driven to perform in response to an obsession, or according to rules that must be applied rigidly. These behaviors or mental acts are usually aimed at preventing or reducing distress or preventing some dreaded event or situation. Importantly, the compulsive behaviors are generally not connected to the worrying thought. For example, a child may be plagued with an obsessive worry that if they don’t turn the light switch on and off perfectly exactly 32 times, he will come home to find his dog slashed and mutilated.

If you think, for a moment, about the common obsessional themes listed in the previous section, you can probably anticipate most of the common compulsive rituals or behaviors that the individual engages in “over and over again:”

  • Washing or hygiene rituals.
  • Counting may be combined with other compulsions. Counting is frequently a “silent ritual.” Teachers may not realize that the student is having to mentally count things while attempting to process or complete work. Since doubting also goes along with OCD, the student may suddenly begin to doubt whether they’ve counted correctly, and may have to start all over again.
  • Checking and re-checking. Individuals who have OCD will check and recheck excessively, whether it is checking to see if they locked the door, turned off the stove or tap, or checking to see if they just ran over someone. It is not uncommon to find patients late for school or work because they spend excessive time checking and rechecking in the home. Assignments may not be submitted on time because the individual is compulsively checking and rechecking their work.
  • Saving or hoarding. In a recent study at Johns Hopkins, about 30% of OCD patients reported hoarding, with males twice as likely to engage in hoarding compulsions as were females. Hoarders were also more likely to engage in skin-picking, nail-biting, and hair-pulling.
  • Seeking reassurance.
  • Ordering or arranging things.
  • Reworking something until it is “perfect.” Children who have perfectionist compulsions in school may have to erase and rework their work until there are holes in it from so much reworking. Perfectionism may also result in the child staying up until all hours of the night getting their homework perfect.
  • Praying, tattling. Some individuals will engage in repeated prayer as a form of penance or to ward off frightening thoughts. Children who have scrupulosity obsessions may feel compelled to speak up when someone has been wronged or falsely accused. Or they may become the class “snitch” because of a need to confess or tell someone what someone else has done.
  • Repeating compulsions. One example is the child who has to read a line backwards after reading it forwards to prevent something terrible from happening. Or the child may have to walk up and down the hall a certain number of times or come through a doorway a particular way a specific number of times. Such compulsions often combine other compulsions such as counting/numbers.
  • Compulsive avoidance. When a particular setting or situation has become associated with compulsive behavior, the individual may start to avoid that situation or setting, for fear that they will lose control and get “stuck” performing the ritual. In other cases, some particular event or stimulus may be associated with horrific thoughts, and the individual will attempt to avoid that stimulus. Children who have gotten “stuck” engaging in a ritual in the gym, for example, may seem reluctant to go to gym the next time it is scheduled and may start offering excuses as to why they can’t go.

In young children, we often find that the very young child does not realize that others are not experiencing the same bizarre intrusive thoughts that they are. As the child gets older and realizes how bizarre the thoughts are, they may be reluctant to tell others what’s going on internally or why they feel the need to do peculiar things.


I know — from experience — that as soon as I start describing OCD and giving examples, at least half the audience will start to worry that they have OCD or will diagnose themselves, so let me introduce a little caution here:

All of us have our habits and “eccentricities.” Such repetitive behaviors or intrusive repetive thoughts do not rise to the level of a “disorder” unless they seriously interfere with your life, cause you significant distress, or consume hours each day.

We will discuss the diagnostic criteria below, but just keep in mind that a certain amount of these types of behaviors is within the realm of ‘normal’ experience.


As with Tourette’s Syndrome and other conditions, the diagnosis of OCD relies primarily on reported history by reliable observers and/or the clinician’s observations and judgment. In the United States, mental health professionals use the DSM-IV diagnostic criteria (opens in a new window) while in Europe, mental health professional generally use the ICD-10 diagnostic criteria.

In looking at the DSM-IV criteria for diagnosis, note that all criteria A – E have to be met, but that Criterion A specifies obsessions or compulsions (emphasis added by me). A patient does not have to have both, although many do.

A Picture Speaks 1,000 Words

From the work of Lewis Baxter, MD, UCLA, 1992


Sometimes a picture does speak 1,000 words. A neuroimaging technique known as Positron Emission Tomography (PET scan) enables us to look at how the brain functions under different conditions and to compare the brains of people with a particular disorder to those who do not have the disorder.

Take a look at the at the difference between the brain of someone without OCD (left image) and the brain of someone with OCD. The extensive red and yellow areas in the right image indicate a lot of brain activity — too much activity. The person is thinking about something “over and over again.”


It has been estimated that 1% of children and up to 4% of adolescents have OCD. In children, OCD appears to be more prevalent in boys, but in adulthood, the ratio of males to females is approximately the same. The age of onset is typically reported as 6 – 15 for males and 20 – 29 for females, but we know that many children (including girls) who have Tourette’s Syndrome also have childhood-onset OCD. More recent research suggests that OCD may have a bimodal (two peaks) distribution of onset. About 1/3 to 1/2 of adult patients who have OCD report that the onset was in childhood or adolescence, before age 10. Those adults who had early onset experienced more sensory phenomena and had a higher rate of tic disorders than those with later-onset OCD (see the Tourette’s overview for a discussion of sensory phenomena and tics). In a fascinating case series, Hazen, Reichert, et al. (2008) describe children with significant intolerance for ordinary sensory stimuli. The sensory intolerance created marked distress and led to compulsive behaviors in the absence of any typical obsessive themes or thoughts. The phenomenon they are describing seems like it is on the boundary of sensory integration dysfunction, Tourette’s Syndrome and OCD.

In terms of long-term outcomes, Soke and Soke (1999) provided a 40 year follow-up on OCD patients. They reported that over 80% of all patients experienced improvement. Almost 50% of the sample had OCD for more than 30 years. The best predictors of both obsessive and compulsive symptoms were early age of onset, low social functioning at baseline, and a chronic course at the examinations conducted between 1954 and 1956. Magical obsessions and compulsive rituals were also correlated with a worse prognosis. In the past few years, several studies have been published that specifically look at age of onset. For a variety of measures and despite differences in methodologies and samples, early-onset OCD seems to be associated with a more severe course or worse outcome. Earlier age of onset also predicts an increased risk for Attention Deficit Hyperactivity Disorder, simple phobia, agoraphobia (fear of outdoor or public places) and multiple anxiety disorders. Mood disorders such as depression or Bipolar Disorder were not predicted by age of onset but were correlated with chronological age: older children and teens with OCD exhibited more depression and/or Bipolar Disorder than younger children.

More recently, Geller (2006) and his colleagues (2007) reviewed some of the similarities and differences between pediatric OCD and adult OCD, and Nestadt et al. (2008) provided preliminary data describing three subtypes of OCD based on comorbidity patterns: (1) an “OCD simplex” subtype where depression is the most frequent comorbid disorder; (2) an OCD-tic subtype, in which tics are prominent and mood syndromes are considerably rarer; and (3) an OCD-mood subtype in which panic disorder and affective syndromes are common. The investigators also found gender x subtype differences: the OCD-tic subtype is predominantly male while the OCD-affective subtype is predominantly female.


John Piacentini and his colleagues at UCLA published the first study to really look at psychosocial impact of OCD on youth (Piacentini, Bergman, et al., 2003).

Using children with OCD referred by a clinic, the investigators had the children and their primary caregivers completed a checklist that inquiried about school, family, and social functioning. Parents tended to report more problems than the children themselves reported, with over 40% of the parents reporting that their children had difficulty concentrating on schoolwork, doing homework, and getting ready for bed at night. Thirty percent or more of the children reported significant problems concentrating on schoolwork, doing homework, and doing household chores. Parent reports and children reports all tended to note more problems in school/academic and home/family functioning than in social functioning. Although there was considerable variability across specific problem areas, 85% of children (by their own report) experienced a significant problem in at least one of the three domains of functioning (home, school, social), and close to half of the sample reported at least one significant problem in each of the three domains.

Although parents tended to report more observed problems than the children reported, the consistency in reports in terms of homework and concentrating on schoolwork should be of special note to educators in planning for these youngsters.