Intrusive Thoughts and ‘Pure O’ OCD: Using ACT Without Making It Compulsive

Oli Hamilton

3 hours ago

6 min read

Large weathered anchor resting on a sandy beach at sunset, with gentle waves and a calm sea in the background.

Intrusive thoughts are unwanted thoughts, images or worries that feel out of control or invasive. They commonly concern harm, relationships, sexuality, morality or health, and can feel completely at odds with who you are. Most people experience intrusive thoughts at some point, and the presence of a thought, by itself, tells you very little about your intentions or personality.

For some people, the thought passes. For others, it sticks. The difficulty then lies less in the thought itself than in the effort to deal with it: going over it, questioning what it means, checking how you feel, looking for reassurance or trying to establish some certainty.

‘Pure O’ is an informal term used to describe OCD in which compulsions are mainly mental, making them less visible to other people. Although some practitioners avoid the term because it can imply that compulsions are absent, compulsions are still very much part of the picture. Repetitive rumination can function as a compulsion just as much as more familiar OCD behaviours, such as excessive handwashing, when it's driven by the need to reduce anxiety or achieve certainty.

Acceptance and Commitment Therapy (ACT) offers a useful way of approaching these patterns. Rather than trying to eliminate unwanted thoughts, ACT encourages us to change our relationship with them, becoming more able to experience uncertainty and discomfort without getting caught up in repetitive thinking.

One of the most established psychological treatments for OCD is CBT incorporating exposure and response prevention (ERP). The ACT approaches in this article can complement that work, but aren't intended to replace it.

Noticing what you're actually doing

One of the difficulties with Pure O is that compulsions can feel like ordinary thinking. You might believe you're being responsible, trying to understand yourself or simply working something out.

Some signs that thinking has become compulsive include:

Replaying conversations to establish whether you said something inappropriate.
Getting into the same familiar mental debates without reaching any new conclusions.
Checking your feelings repeatedly to establish whether you love your partner.
Questioning whether your thoughts make you a bad person or reveal something about your identity.
Searching online for explanations or reassurance.
Avoiding people, places or situations that might trigger unwanted thoughts.

These behaviours can provide temporary relief, but the doubt often returns and the cycle starts again.

A useful question to ask yourself is: Is this thinking helping me respond to something that matters, or am I getting caught in an attempt to find certainty or make an uncomfortable feeling go away?

If it's the latter, you might practise noticing the urge without following it. This is closely related to the response prevention part of ERP, and it's often the hardest part.

It's important to distinguish this from simply trying to suppress the thought. Trying to push unwanted thoughts away can sometimes make us more preoccupied with whether they're still there. Getting frustrated with yourself for having a thought can add another layer of struggle. I've explored this distinction further in Intrusive Thoughts: When Trying to Let Go Becomes Another Struggle.

Dropping Anchor

Russ Harris describes an exercise called Dropping Anchor in The Happiness Trap. Imagine a boat in rough water. Dropping its anchor doesn't stop the storm or flatten the waves, but it provides some stability while they continue around it.

The exercise uses three steps, known as ACE:

A – Acknowledge what's happening inside you.

Name it plainly: I'm having an intrusive thought. I'm anxious. There's an urge to work this out. You don't need to establish why the thought appeared or what it means.

C – Connect with your body.

Feel your feet on the floor, press your fingertips together or notice the weight of your body against the chair. You're not trying to relax or change how you feel; you're reconnecting with your physical experience.

E – Engage with the world around you.

Notice what you can see and hear, then decide what you want to do next. Perhaps you return to a conversation, carry on with your work or finish making dinner. The thought and anxiety might still be there, and you do the next thing anyway.

There's something important happening here. When we're caught up in an intrusive thought, our attention can become almost entirely consumed by our internal experience. We become absorbed in the content of the thought, the feelings it produces and the urge to do something about it.

Dropping Anchor helps us broaden our awareness. We can acknowledge what's happening internally while also making room for our physical experience and the world around us. We're not choosing between paying attention to our thoughts and ignoring them; we're learning that our thoughts don't have to occupy our entire field of attention.

There's an important distinction, particularly for OCD, between using this exercise to reconnect with the present and using it to make anxiety disappear. If you start checking whether it has worked, repeating it until you feel better or becoming frustrated when the anxiety remains, it can become another compulsion. The intention is to show yourself that you can experience the thought and the feeling while continuing with what matters, whether or not you feel better.

Defusion: learning to unhook from intrusive thoughts

Defusion is about recognising thoughts as things our minds produce, rather than automatically treating them as facts, instructions or important messages about ourselves.

People experiencing intrusive thoughts can become cognitively fused with them, meaning they experience the thoughts as particularly significant or feel compelled to investigate their content.

For example, someone might have an intrusive thought about causing harm and immediately start questioning whether it means they're secretly dangerous. Defusion offers an alternative to entering that debate.

A few simple exercises can help:

Name the thought. Instead of becoming absorbed in its content, try saying: I'm noticing I'm having the thought that I might be a bad person. This creates some distance between you and the thought.

Thank your mind. Russ Harris suggests responding with something like, "Thanks, mind, for that one." It's a way of acknowledging that minds produce worries, predictions and strange ideas, without needing to act on every one.

Recognise familiar patterns. If you repeatedly find yourself caught in the same mental loop, you might simply acknowledge: There's that familiar story again.

The important thing is not to use these techniques to neutralise the thought or prove that it means nothing. They are most useful when they help you leave the thought unresolved.

Back to what you care about

Intrusive thoughts and the rituals that follow them can gradually take up more and more of your time. You might avoid activities, withdraw from people or spend much of your day trying to establish certainty.

ACT encourages us to reconnect with our values: the things that matter to us and the qualities we want to bring to our lives and relationships.

A useful question is: If I wasn't spending so much time trying to resolve these thoughts, what would I be doing?

Perhaps you'd be more present with your family, spend time with your partner without repeatedly checking your feelings, go out socially or return to activities that rumination has pushed aside.

The aim is to move towards those things with the thoughts in tow, rather than waiting until they disappear.

There are other ACT processes worth exploring too, including expansion (making room for uncomfortable physical sensations without fighting them) and the observing self (the part of you that notices thoughts, allowing thoughts to exist without being defined by them). Both are explored in Harris's book.

Where this fits with treatment

NICE guidance recommends considering CBT incorporating exposure to obsessive thoughts and prevention of mental rituals and neutralising strategies for adults experiencing obsessive thoughts without overt compulsions.

ACT also has a growing evidence base for OCD. A 2010 randomised trial by Twohig and colleagues, involving 79 adults, found that ACT produced greater improvements in OCD symptoms than progressive relaxation training. A 2023 systematic review by Evey and Steinman examined 17 studies involving 336 participants and found encouraging results, while highlighting the need for more rigorous research.

ACT principles can also complement ERP, helping people develop greater willingness to experience uncertainty and uncomfortable thoughts and feelings without resorting to compulsive responses.

How psychotherapy can help Pure O OCD

For some people, intrusive thoughts become connected to deeper concerns about identity, responsibility, relationships or the ability to tolerate uncertainty. Psychotherapy can provide an opportunity to explore these patterns, understanding not only how they operate but why particular experiences might become so significant.

I take an integrative approach, combining an interest in the underlying psychological patterns that shape our experiences with practical ways of working with anxiety and intrusive thoughts. This might involve drawing on ACT principles, exploring avoidance and reassurance-seeking, and developing a greater capacity to tolerate uncertainty. Where relevant, I also consider the broader picture of who you are and how your life experiences may have shaped the way your mind works, while ensuring that therapy doesn't become another opportunity to get caught up in certainty-seeking and rumination.

If you're struggling with intrusive thoughts or find yourself caught in repetitive mental rituals, you can get in touch to discuss whether psychotherapy might be helpful. You can find out more about my approach on my Psychotherapy page.

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