When most people picture obsessive-compulsive disorder (OCD), they often imagine behaviors they can see: excessive handwashing, repeatedly checking locks, arranging objects until they feel “just right,” or performing a ritual a certain number of times. But OCD doesn’t always look like that. For some people, most of the struggle happens internally. They may experience disturbing intrusive thoughts, replay conversations for hours, analyze their feelings, search their memories, or repeatedly try to convince themselves that everything is okay. Because these compulsions happen primarily inside the mind, this experience is sometimes referred to as “Pure O,” or primarily obsessional OCD.
The term “Pure O” can be somewhat misleading because people experiencing this form of OCD typically do have compulsions, they’re simply harder to see. Instead of washing, checking, or arranging, the compulsions may involve rumination, mental reviewing, analyzing memories, checking feelings, seeking reassurance, or repeatedly talking themselves through an intrusive thought.
OCD generally operates through a cycle: an intrusive thought or doubt creates anxiety or discomfort, which leads to a compulsion intended to reduce that discomfort. The compulsion may provide temporary relief, but that relief teaches the brain that the intrusive thought was important and needed to be resolved. Eventually, another doubt appears, and the cycle starts again.
Imagine someone suddenly thinks, what if I said something offensive during that conversation? They may begin replaying the interaction, trying to remember exactly what they said, examining the other person’s facial expressions, or telling themselves, I know I didn’t say anything wrong. Eventually, they may feel better. But then another thought appears: What if I’m remembering it incorrectly? The compulsion may not be visible to anyone else, but the OCD cycle is still happening.
When Thinking Becomes a Compulsion
One of the most common covert compulsions is mental reviewing. Someone may repeatedly replay a conversation or event in an attempt to determine exactly what happened. They might wonder whether they sounded rude, whether another person seemed upset, or whether they accidentally crossed a line. Simply remembering an event is not a compulsion. It becomes problematic when the person feels driven to review it repeatedly in order to eliminate uncertainty or obtain a sense of reassurance.
Rumination works in a similar way. It can feel productive because it resembles problem-solving. Someone may believe that if they think about something long enough, eventually they will find the answer that allows them to move on. They may spend significant amounts of time asking themselves, what does this thought mean about me? Why did I think that? Would a good person have that thought? What if I secretly wanted it? How do I know how I really feel?
The problem is that OCD rarely accepts an answer for very long. One answer tends to produce another question. The person may finally conclude, No, that thought doesn’t represent who I am, only for OCD to respond with, but how can you be completely sure?
Mental compulsions can also involve repeatedly checking emotions and physical reactions. Someone experiencing relationship OCD might continually ask themselves whether they feel enough love toward their partner. Someone struggling with intrusive thoughts about identity or attraction might monitor how they feel around certain people. A person experiencing harm-related obsessions may analyze whether an intrusive image upset them “enough.” Instead of allowing feelings to occur naturally, the person begins observing, measuring, testing, and analyzing every internal experience.
Memory can become another target. A person may search through past experiences looking for evidence that proves or disproves an obsession. They might ask themselves, Have I ever felt this way before? Did something happen when I was younger that explains this? What if I did something inappropriate and don’t remember it correctly? Because human memory is naturally imperfect, trying to achieve complete certainty about the past can actually create even more doubt.
Even positive self-talk can sometimes become part of the OCD cycle. Statements such as “I would never hurt anyone,” “I know I’m a good person,” or “That was just an intrusive thought” may sound helpful and sometimes they are. However, if someone feels compelled to repeat these statements until their anxiety decreases, they may be functioning as reassurance. With OCD, it can be helpful to look not only at what someone is doing, but why they are doing it.
The Reassurance Trap
Reassurance seeking is another compulsion that can easily go unnoticed. Someone may repeatedly ask a partner, friend, family member, or therapist questions such as, “Do you think I did anything wrong?” “Would you tell me if you were upset with me?” or “You don’t think this thought means anything, right?”
Reassurance can also happen without asking another person directly. Searching Google, reading forums, comparing your experiences with someone else’s, researching symptoms, or repeatedly looking up whether a particular thought is “normal” can all serve the same purpose: trying to obtain enough information to finally feel certain.
The difficult part is that reassurance often does make someone feel better temporarily. That short-term relief is what makes the behavior so reinforcing. The brain learns, When I feel uncertain, I need to do something to make sure I’m okay. Over time, the person may become increasingly dependent on reassurance to manage uncertainty.
Treating Pure O
Treatment for Pure O is not about learning how to eliminate intrusive thoughts. Everyone experiences unwanted, strange, uncomfortable, or upsetting thoughts from time to time. Trying desperately not to think about something can actually make us more aware of it. Instead, OCD treatment focuses on changing the way someone responds when those thoughts appear.
Exposure and Response Prevention (ERP), a frontline behavioral treatment for OCD, helps people practice experiencing uncertainty and discomfort without performing the compulsions that usually follow. For someone whose compulsions are primarily mental, response prevention may involve noticing the urge to replay a conversation and choosing not to review it again. It might mean experiencing the thought “What if I did something wrong?” without spending the next hour trying to determine whether it is true.
Rather than proving an intrusive thought wrong, someone might practice responding with, “Maybe, maybe not,” “I don’t need to figure this out right now,” or “I can allow this question to remain unanswered.” These responses aren’t meant to provide another form of reassurance. Instead, they represent a willingness to stop participating in OCD’s demand for absolute certainty.
The goal is not to become certain. The goal is to become more comfortable moving forward without certainty.
Pure O can be particularly exhausting because someone may appear completely calm on the outside while internally spending hours debating, reviewing, checking, analyzing, and reassuring themselves. Recognizing these behaviors as compulsions can be an important part of breaking the cycle.
When an intrusive thought appears, instead of immediately asking, “How do I make this thought go away?” it can be helpful to ask a different question: What is OCD asking me to do in response to this thought? Is it asking me to review, analyze, check, research, seek reassurance, or figure something out with complete certainty?
The intrusive thought itself isn’t always what keeps someone stuck. Often, it’s everything they feel compelled to do afterward.
Learning to recognize these invisible compulsions and gradually choosing not to engage with them—can create space for something OCD often takes away: the freedom to experience uncertainty and continue living your life anyway.
