OCD is well known for its implausible obsessions and repetitive, often bizarre, compulsions. Indeed, compulsions are typically the most noteworthy and visible facet of the disorder, making OCD-themed TV programs ideal for the public during ratings week. Just tune-in any time you need to convince yourself that whatever weird habits you have aren't nearly as bad as that guy who's driving his car in mad circles to be sure he hasn't unwittingly run over someone.

However, many people with OCD find they have no obvious compulsions, only the repetitive mental agony of taboo thoughts that won't go away. These thoughts typically include , religion, and . And although you'd think obsessions of this sort would make for some really compelling TV, you almost never hear about people with this kind of OCD. Why? Because most of the action is taking place inside the person's head, where you can't see it. These people are sometimes called pure-obsessionals, or pure-o for short.

The OCD Cycle

Although we don't know the exact cause of OCD in any one person, we do know quite a bit about how the disorder is maintained. You can think of OCD as a set of habits that involve intrusive thoughts that something very bad might happen (obsessions), followed by an urge to do something to prevent the bad thing from happening (a compulsion). The compulsion reduces the distress momentarily, and so the person gets into the habit of using these various special behaviors to get rid of the . When someone does this over and over again, we call it a compulsive ritual. Of course, rituals are only a temporary fix, as the obsession always comes back. In fact, the more compulsions you do, the stronger the OCD becomes.

This understanding of the OCD cycle is what gives we therapists our strongest tool for taking down the OCD demon, using a treatment called Exposure and Ritual Prevention (EX/RP). Interestingly, the fewer compulsions the person does, the weaker the OCD gets, so clients are taught how to stop doing rituals and embrace the anxiety. I tell my clients to think of OCD as a fire, and every time you do a compulsion, you're throwing it a log. Once the fuel stops coming, the fire dies out.

So, based on what we know about how OCD is maintained, it is actually impossible for someone with OCD to only have obsessions, because OCD will eventually peeter out with no compulsions to feed it. In short, pure-o can't exist.

The DSM and the Pure Obsessional

But what do the experts say? The psychiatrist's bible, the DSM ( , Version 5), doesn't help us much in figuring this out.

The current version of the DSM requires that either obsessions or compulsions be present for a diagnosis of OCD. However, as mentioned above, this is actually a contradiction. DSM itself notes a functional relationship between obsessions and compulsions, since compulsions are performed in response to an obsession. So you can't have one without the other.

To better understand OCD symptoms, the fourth edition of the DSM sponsored a huge study where they examined hundreds of OCD patients at OCD-specialty clinics across the country. They found that 96% of adults with OCD had both obsessions and compulsions when evaluated by well-trained raters, with only 2% having "predominantly obsessions." Thus, it would seem that pure-obsessionals are few and far between.

Source: iStockPhoto

So, where did we even get the idea that the pure-obsessionals may be out there at all? The first study to really take a scientific look at OCD symptom clusters was published by Lee Baer in 1994. He studied 107 OCD patients who had completed a long checklist of OCD symptoms called the Yale-Brown checklist. He found three types of OCD that he called Symmetry/ , Contamination/Checking, and Pure Obsessions. This last subtype included people with aggressive, sexual, and religious obsessions, but no compulsions. Thus it was believed that the "Pure Obsessions" group had no rituals, just their own troubled thoughts.

However, at that time no one was really taking a good hard look at other types of compulsions that aren't so flashy. For example, consider a woman with OCD who gets unwanted thoughts to stab her husband with a steak knife. She might do any number of compulsions to make the thought go away. She might mentally retrace her steps to be sure she didn't touch a knife. She might do repetitive silent prayers that no harm come to her husband. She might take a mental inventory of all the good things she's done to convince herself that she's a morally upright person. She might ask for reassurance from her husband that she's a good person and would never do such a terrible thing. These types of behaviors are sometimes called covert rituals because you don't actually see the compulsions in the same way you do when someone can't stop washing their hands.

Covert rituals can include a variety of behaviors, such as mental compulsions and reassurance-seeking. Mental compulsions may include mental repetition of special words, mental reviewing, and mental un-doing. Reassurance-seeking may include asking others for reassurance, , or confessing to others. Even internet searching can be a covert compulsion as the person with OCD seeks reassurance online in forums, chat rooms, or information websites — much in the same way a seeks reassurance from doctors.

Pure-O and Covert Compulsions: The Link

New research shows that if Baer had included these types of rituals in his study, he might have had some very different findings. When mental rituals and reassurance-seeking are added into the equation, they fall neatly into the category that Baer had termed Pure Obsessional. So, it seems quite possible that the pure obsessional just doesn't exist.

The bottom line: people who think they are pure-o are likely doing covert compulsions. for OCD is extremely effective, but it requires a thorough examination of both the client's obsessions and compulsions. If someone with OCD gets EX/RP, but the covert rituals are not addressed, then treatment will be incomplete which can lead to a speedy . Clinicians treating OCD need to always address covert rituals. People with OCD need to understand that these acts are part of the clinical picture.

So, whenever clients tell me they have only obsessions and no compulsions, I ask about mental rituals and reassurance. "Oh yeah, I do that a lot," they invariably say. "So, that's a compulsion?" Yes, that's a compulsion.

Learn more at OCD Types.