Types of OCD

Pure O: intrusive thoughts, hidden compulsions

"Pure O" is the name people find when their OCD happens entirely inside their head. The name is wrong in one important way, and seeing why is the first step out of the loop.

What is Pure O?

Pure O, short for "purely obsessional" obsessive-compulsive disorder (OCD), is an informal name for OCD where the compulsions happen mentally instead of visibly. The person has intrusive thoughts, often about taboo subjects, and responds with hidden rituals, what clinicians call compulsions: rumination, mental review, silent self-reassurance, avoidance. It's OCD, and it responds to the same first-line treatment, adapted for mental compulsions.

The name took hold because from the outside there's nothing to see. Nobody catches you washing your hands. You aren't washing your hands.

What's actually going on may be more like this. You're at dinner, quiet, apparently listening, and inside you're on the fourth pass through something you said this morning, checking whether you meant something terrible by it. Or you're scanning your body for the "wrong" reaction to a thought. Or it's the arguing. Some people spend two, three hours a night arguing with one thought, and I mean real arguing, with evidence and counterarguments, like a court case nobody else can hear.

If that sounds like your evenings, this page is about you. I want to walk through the loop itself, because the mechanics are where the way out is. That's true of OCD generally, but it's especially true here, where the whole thing is invisible.

Can you have OCD with only intrusive thoughts?

OCD can involve obsessions, compulsions, or both, and in so-called Pure O the compulsions are there but mental: rumination, reviewing, checking how a thought felt, and silent self-reassurance. They're harder to see, and they keep the cycle running the same way washing and checking do.

Start with the thoughts, because honestly, the thoughts are not the unusual part. In a study of 777 university students across 13 countries, 93.6% reported at least one intrusive thought in the previous three months. Researchers went looking on six continents and mostly could not find people who don't have strange, ugly, out-of-nowhere thoughts. They're just part of having a brain.

Maybe you're already thinking, sure, but mine are different. Mine are worse. Mine say something about me.

I hear a version of that in first appointments all the time. It's OCD's most reliable line.

So what actually separates OCD, if almost everyone has the thoughts? For most people a strange thought passes through and it's gone by lunch. In OCD the thought arrives as a message that has to be settled, and the settling is where your hours go. The reviewing, the testing yourself, the quiet self-talk. That work is the compulsion half of the disorder. Maybe nothing happens physically, but it's still the compulsion half of the disorder.

One more clinical fact belongs here, because these thoughts often run to the taboo kind, harm or sexuality or blasphemy. In OCD, thoughts like these are intrusive and unwanted, the opposite of a wish, and clinicians who know OCD read them that way.

What is rumination, and why is it the hidden compulsion?

Rumination, generally speaking, just means going over something in your mind again and again. In obsessive-compulsive disorder it takes a more specific form, a ruminative compulsion: engaging with the intrusive thought, arguing with it and testing it and trying to reach certainty about it. "I ruminate all day" feels like a description of the obsessions. In OCD it's usually a description of the compulsions.

Let me take a minute with this one, because when it clicks, people see the same day differently. The hours they blamed on the thoughts were mostly spent on compulsions. It's worth being slow here even if you half-know it already.

The thought that arrives uninvited, that's the obsession. You don't choose it and you can't choose it away. I want to be really clear about that part, you can't, and trying to is itself a form of engaging.

Everything after the thought arrives is behavior. The reviewing is behavior. The arguing is behavior. Even that quiet "you're fine, you'd never do that" you give yourself, the one that buys about an hour, that's behavior too, even though it feels like comfort rather than a compulsion. Nothing happens physically, but the mental behavior is the compulsion nonetheless.

And behavior is the part treatment can change. Not the thought. The thought was never the part you controlled anyway.

Why does ruminating make it worse?

Each round of rumination treats the intrusive thought as a question that has to be settled. That teaches the brain the thought is important and dangerous enough to deserve the work. The relief after "settling" it is real but temporary. The doubt comes back, and the cycle has been rehearsed one more time.

From the inside, the rumination feels productive. The analysis is real effort, and effort feels like progress. What actually happens though is often more that a thought shows up, you react to it, review the evidence or battle with it, and if you're lucky you find the angle that finally makes things feel settled. Relief, maybe an hour of it. Then the doubt is back with a new "but what if," and your brain has had one more rehearsal at treating this thought like an emergency worth working on.

The way I often put it to patients is that the anxiety riding along with the thought is an alarm, and it's going off like the world's ablaze when what's actually there is more of a burnt toast situation. You can't argue an alarm quiet. And you can't out-research it either, because OCD is ultimately an illness of uncertainty intolerance. The reviewing is chasing certainty, and certainty is the one thing it can't produce. People do get sick. Words do get taken the wrong way. There's no guarantee coming about the things you care about most, for you or for anyone, and with OCD that missing guarantee is the intolerable part. So you go back to work on the question, the work buys an hour, and the alarm learns to fire again tomorrow.

A way of thinking about it that tends to stick with people is that the doubt is a what if, and the rumination is you trying to answer something unknowable with certainty. The work isn't to win the argument. It's to sit with maybe, or to walk away from the argument altogether, because you just don't get to know right now. As difficult as that seems, it's what helps you in the long run. People in treatment call it sitting with the maybe, and it's a skill you can practice, not a personality trait.

If you've searched this before

Maybe tonight is the first time you've looked Pure O up. Or maybe this is the fourth article tonight, in which case the searching itself is part of the pattern this page has been describing, and I'd offer you the same question I ask in my office when somebody wants one more answer from me. Are you reading about mental compulsions because you don't know what they are? Or is it because you "want to be sure" that's what's going on for you? If you're trying to "be certain" or "just be sure", you may be reading as a compulsion.

No scolding either way, truly. But you've probably noticed how this goes. The answer holds for an hour, sometimes a day if it's a good one, and the doubt comes back with a new angle. Closing the tab with the question still open is the same practice this whole page is about. It's available right now and it's free.

How is Pure O treated?

Pure O is treated with exposure and response prevention (ERP), the same first-line treatment as all obsessive-compulsive disorder, adapted for mental compulsions. The response being prevented is the rumination itself, learning to let an intrusive thought sit unanswered. The International OCD Foundation puts a typical course at 12 to 20 sessions, and medication is part of care for some adults, decided with a prescriber.

One warning about therapy that isn't built for OCD, because this comes up a lot with this presentation. The compulsions are invisible, so a therapist who doesn't know the disorder can spend months exploring the thoughts as meaningful material. What does this thought mean about you, where does it come from, that kind of thing. Exploring the thoughts is rumination with company. If your current therapy has never named rumination as the target, say so out loud in the room. The questions that vet an OCD therapist are fair to ask anyone, including someone you already see and like.

And to be fair to the therapists, the missing-it problem is bigger than any one room. When researchers gave primary care doctors written descriptions of OCD, half the time the doctors called it something else. The versions built on sexual and aggressive intrusive thoughts got missed most often. The full picture is in the treatment-gap numbers, but the short of it is that if this page is the first time your evenings have had a clinical name, that's a common story. The delay wasn't you being slow.

The name is real and the treatment is real. The way out runs through learning to leave the argument unfinished, and getting your evenings back while it sits there.