Pure obsessional OCD (pure O) is a subtype of OCD where compulsions happen mentally instead of physically. People with pure O experience distressing intrusive thoughts and engage in hidden compulsions like rumination, mental reviewing, and silent reassurance-seeking.
When you think of obsessive-compulsive disorder (OCD), you might picture someone washing their hands repeatedly or checking the stove over and over. These physical compulsions are well-known, but what if your struggle with OCD doesn’t look like that? What if you’re stuck in an endless loop of distressing thoughts, questioning why you can’t stop thinking about something—yet there’s nothing visible on the outside?
If that sounds familiar, you’re not alone. Many people with OCD don’t engage in physical rituals, but that doesn’t mean they aren’t performing compulsions. Instead, these compulsions happen mentally—through rumination, reassurance-seeking, or analyzing thoughts in an attempt to find certainty. This is called pure obsessional OCD, or pure O. Since it’s less talked about, you might feel unseen, wondering if what you’re experiencing is really OCD at all. But Pure O is real, it’s common, and—most importantly—it’s treatable with the right support.
What is pure obsessional (pure O) OCD?
Pure obsessional obsessive-compulsive disorder (OCD) is a subtype of OCD that’s characterized by intrusive thoughts, feelings, images, or urges without any visible physical compulsions. Pure OCD differs slightly from other types of OCD because its compulsions primarily take place in a person’s head rather than through visible actions. This could manifest as mentally replaying events over and over again in your mind, silently repeating phrases in your head, becoming hyper-aware of normal bodily sensations—just to name a few.
Though they can take many forms, these intrusive thoughts generally center on themes of harm, relationships, sexuality and gender, and religious or moral questions. These ideas and images can feel like an attack on a person’s sense of self and they often come with guilt and shame.
Many people with pure OCD are terrified of sharing these experiences for fear of being judged. “It’s common for people with ‘pure O’ OCD to feel like they are the only ones dealing with this,” shares Dr. Nicholas Farrell, Director of Clinical Development and Programming at NOCD. Because their experience is internal, there often aren’t obvious visual clues an outside observer might notice to identify someone with pure OCD, but that makes it no less distressing.
Is pure O just OCD without compulsions?
No, pure O is not OCD without compulsions—it’s OCD with mental compulsions rather than physical ones. A common misunderstanding is that pure O only involves obsessive thoughts without any response, but that’s not the case. People with pure O engage in compulsions, just like those with more outwardly visible forms of OCD—the difference is that these compulsions happen internally.
Since these compulsions don’t involve obvious physical actions, people with pure O often feel misunderstood or question whether they really have OCD. But just like all forms of OCD, pure O follows the same cycle of obsession, compulsion, and temporary relief—only for the distress to return.
What does pure OCD feel like?
Although it might sound surprising, it is relatively common to have a disturbing or immoral thought, impulse or urge—regardless of OCD diagnosis. The difference is, for people without OCD, these thoughts tend to last only a few seconds and don’t cause significant distress. A person may be driving and suddenly think to themselves, “What would happen if I drove off this bridge?” But they’ll shortly dismiss the idea and move on.
For someone with pure OCD, these intrusive thoughts can be frequent and highly distressing. “They will identify with the thought and feel convinced it reveals something about who they are as a human being,” Dr. Farrell explains. They might think, “I just had a dream about harming someone—that means I must be a violent person.”
It can feel impossible to separate yourself from these thoughts when they occur. The experience can feel so real, you can’t imagine your thoughts are actually from OCD. Someone with pure OCD may want to prove or disprove one of their intrusive thoughts (for example: “I would never jump off this ledge, but how can I know for sure?”), feeling unable to tolerate any uncertainty about them and searching for a feeling of safety. A person with pure OCD may even doubt their diagnosis. They might think, “Maybe this time, my thoughts actually mean I want to hurt someone.”
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Examples of pure OCD obsessions and compulsions
People with pure OCD experience obsessions, which are unwanted, distressing thoughts, images, or urges that feel intrusive and difficult to ignore. In response, they engage in compulsions, repetitive mental acts or behaviors aimed at reducing anxiety or uncertainty. Even though these compulsions might bring brief relief, they actually reinforce the OCD cycle, making the obsessions stronger over time.
Here are two examples that Dr. Farrell highlights:
- Obsession: While sharpening her pencil in class, Jennie suddenly has the thought, This pencil is really sharp, followed by an intrusive image of hurting a classmate. Panic sets in as she wonders, What if I actually hurt someone?
- Compulsion: Jennie starts reviewing every past interaction with classmates, scanning for signs that she has ever acted violently. Even after class, she continues mentally replaying her day, trying to reassure herself that she isn’t dangerous.
- Obsession: While watching a movie with his partner, Taylor notices they didn’t laugh at a joke he found funny. This sparks a flood of anxious thoughts: What if we’re not compatible? What if we have nothing in common?
- Compulsion: To quiet his distress, he mentally repeats I love my partner five times, or visualizes a happy memory to cancel out his doubts. Though this provides temporary relief, the uncertainty always creeps back, forcing him to repeat the ritual again and again.
Because pure OCD compulsions happen in the mind rather than through physical actions, they can be difficult to recognize—but they are just as powerful in maintaining OCD’s cycle. The good news is that treatment, especially exposure and response prevention (ERP) therapy, can help individuals break free from these patterns and regain control over their lives.
Hidden compulsions in pure O
Since compulsions in pure O happen internally, they’re often referred to as hidden compulsions—actions that might not be noticeable to others but still play a central role in maintaining OCD’s cycle.
A few more examples of these so-called hidden compulsions include:
- Rumination: replaying events or thoughts to analyze them for reassurance
- Silent reassurance-seeking: repeatedly telling yourself “I would never do that” or “This thought doesn’t mean anything”
- Thought neutralization: replacing a “bad” thought with a “good” one to cancel it out
- Hyper-awareness: obsessively monitoring sensations, emotions, or thoughts
What’s the best treatment for pure OCD?
Even though pure OCD is not always noticeable from an outside perspective, it is still treated like all other OCD subtypes: with exposure and response prevention (ERP) therapy. ERP is an evidence-based form of cognitive behavioral therapy (CBT) developed specifically for OCD.
For pure OCD, a trained ERP therapist will be able to help you identify your mental compulsions and work with you to come up with the best course of treatment for exposure and response prevention.
“If you’ve ever tried not thinking about something, you know how difficult it is to control your thoughts. ERP therapy takes the opposite approach—instead of trying to make yourself stop your obsessive thoughts, you welcome them,” says Dr. Farrell.
Let’s say that each time you’re driving, you can’t stop seeing mental images of your car running over a pedestrian. This scene starts appearing in your mind every time you drive past a school or busy street downtown. As a way of coping, you’ve started counting to seven in your head each time you see an image like this. This strategy worked at first, but lately it has been less effective. So, as a way to take extra precaution, you’ve decided to count to 49 instead of seven.
Dr. Farrell says he may ask someone with these intrusive thoughts to welcome the intrusive image of running over a pedestrian without trying to make it go away. “You might think, ‘Welcome it? No way! That’s terrible. I just want these images to stop,’” he shares.
But instead of trying to suppress them, a therapist may ask you to put your full attention on these thoughts. “This teaches your brain a new response to your intrusive thoughts and shows you that they don’t have to keep you from living your life,” Dr. Farrell explains.
ERP helps you build tools to distinguish yourself from your OCD thoughts, making it far easier to let them come and go without engaging in compulsions or avoidance. “When I lead collaborative treatment with people who struggle with pure OCD, I find that the tools they develop can last for a lifetime, entirely changing their relationship with uncertainty and anxiety,” Dr. Farrell shares.
Bottom line
Struggling with OCD can feel isolating—especially when your compulsions aren’t visible to others. If you’re stuck in cycles of intrusive thoughts, constantly analyzing, seeking reassurance, or trying to neutralize distressing ideas in your mind, you’re not alone. Pure obsessional OCD follows the same cycle as other forms of OCD, even though the compulsions happen internally.
The good news is that pure OCD is highly treatable. Exposure and response prevention (ERP) therapy helps people learn to sit with uncertainty and break free from compulsions. With the right support, it’s possible to regain control and live a fulfilling life beyond OCD.
Key Takeaways
- Pure obsessional OCD (pure O) includes mental compulsions. Though not visible, compulsions like rumination and reassurance-seeking maintain the OCD cycle.
- Hidden compulsions keep OCD going. Even if they aren’t visible, mental rituals still fuel anxiety and the urge for certainty.
- Exposure and response prevention (ERP) therapy helps break the OCD cycle by teaching you to resist compulsions.