You replay the same conversation, trying to remember exactly what you said. You check your feelings to see whether you love your partner enough. Or an upsetting thought shows up, and you spend hours trying to figure out what it means about you.
From the outside, you might look like you’re simply going about your day. Inside, it can feel like your mind won’t give you a break.
When people think of obsessive-compulsive disorder (OCD), they often picture handwashing or checking the stove. But compulsions can also happen entirely in your mind. This is often what people mean when they use the term “Pure O.”
What does Pure O mean?
Pure O is short for “purely obsessional.” It is an informal term, rather than a separate diagnosis, used to describe OCD where intrusive thoughts are prominent and compulsions are less visible. It’s very rare that there is an absence of compulsions, rather they are mental compulsions are hard for others to notice.
The name can be misleading. It suggests someone has obsessions without compulsions, when often the compulsions are happening mentally. A person might be reviewing, analyzing, counting, or trying to reassure themselves without anyone noticing.
Calling the term misleading does not mean the experience isn’t real. Hidden rituals can be exhausting and can interfere with relationships, work, and everyday life.
Obsessions and mental compulsions: What’s the difference?
An obsession is an unwanted thought, image, urge, or doubt that brings distress. For example: “What if I said something offensive without realizing it?”
A mental compulsion is something you do in your mind to try to resolve that doubt, reduce distress, or prevent something bad from happening. For example: replaying the conversation over and over until you feel certain you didn’t offend anyone.
Both involve thinking, which can make them difficult to tell apart. One useful distinction is the unwanted doubt that shows up versus the mental work you feel driven to do to settle it. In other words, an obsessive thought or image is passive and often purposeless, while a compulsion is active and feels purposeful.
That mental work can become so familiar that you barely notice you’re doing it. Recognizing it takes practice; it isn’t a matter of simply choosing to stop thinking.
What can mental compulsions look like?
Mental rituals can take many forms, including:
● Replaying memories: Reviewing a drive home to make sure you didn’t hit someone, or revisiting a conversation to check whether you lied.
● Checking feelings: Repeatedly testing whether you feel enough love, attraction, guilt, or anxiety, and trying to decide what the answer means.
● Analyzing thoughts: Trying to work out exactly why an unwanted thought appeared or what it says about your character.
● Replacing thoughts: Trying to cancel an upsetting image with a pleasant one, or repeating a “good” thought until it feels right.
● Reassuring yourself: Repeatedly building a case in your mind to prove that your fear cannot be true.
● Counting or repeating words: Following a mental rule until something feels safe, complete, or “just right.”
The behaviour alone doesn’t tell us whether it is a compulsion. Reflecting, praying, or comforting yourself is not automatically OCD. What matters is the purpose and pattern: do you feel driven to repeat it to remove doubt or prevent a feared outcome, even when it keeps you stuck?
Why thinking it through doesn’t always bring lasting relief
Mental compulsions can feel like responsible problem-solving. You might think, “If I review this one more time, I’ll finally be able to move on.”
Sometimes you do feel better….for a little while. Then another question appears: “But what if I missed something?”
The cycle starts again:
Unwanted doubt → distress → mental ritual → temporary relief → more doubt.
Over time, that relief can strengthen the urge to perform the ritual again. The search for certainty starts taking up more time, without giving you a lasting answer.
How does ERP therapy help with Pure O?
Exposure and response prevention (ERP) is an evidence-based treatment for OCD, including presentations with mental compulsions.
ERP involves gradually approaching situations or thoughts that trigger OCD while practicing a different response to the urge to ritualize. With mental compulsions, that means identifying what happens internally as well as what happens outwardly.
For example, someone who repeatedly reviews conversations might practise leaving a conversation without mentally checking every sentence afterward. The therapist and client plan this together, at a manageable level.
The goal is to build the ability to carry on with life while some doubt or discomfort remains. It is not to force thoughts away or guarantee that you will never feel anxious.
For mental rituals, an especially useful distinction is allowing a thought to be present while practising stepping out of the effort to solve or cancel it. This can be challenging, and support can help you recognize when a ritual has quietly returned.
Support for OCD at STC Therapy
You don’t need visible rituals for your distress to deserve attention. And you don’t need to arrive with a perfect explanation of what is happening in your mind.
At STC Therapy, I support adults experiencing OCD symptoms through virtual therapy in Ontario, including people in Halton, the GTA, and the Waterloo region. Together, we can explore the patterns keeping you stuck and use ERP to work toward spending less time caught in rituals and more time doing what matters to you.
If this sounds familiar, visit STC Therapy to book a free consultation. You’re welcome to reach out whether or not you have a formal OCD diagnosis.
This article was informed by the NOCD webinar “The Myth of Pure O: Understanding Mental Compulsions in OCD,” presented by Taylor Newendorp, MA, LCPC. It is written in original wording and is intended for general education, not individual diagnosis or treatment.
wording and is intended for general education, not individual diagnosis or treatment.
Further reading:
● ADAA: Demystifying Mental Compulsions and “Pure-O”
● International OCD Foundation: Exposure and Response Prevention