Pure O - Why Intrusive Thoughts Feel So Distressing

What Is “Pure O”?

“Pure O” (short for purely obsessional OCD) is a phrase many people use to describe OCD where the compulsions are mainly mental rather than outward behaviours.

Someone with Pure O may not wash their hands dozens of times or check locks repeatedly. Instead, the compulsions happen in the mind: analysing, replaying, reassuring, or neutralising intrusive thoughts.

In reality, Pure O is not a separate diagnosis — it’s simply OCD that shows up with covert rituals. These include: rumination, mental checking, self-reassurance, memory scanning, thought-neutralising phrases, silent counting, or Googling for certainty.

When people with Pure O search for OCD therapy in Edinburgh or online, they often say:

• “I don’t do compulsions — I just get stuck in my head.”

• “My thoughts feel unbearable and I can’t let them go.”
  

Understanding the common features of this form of OCD can be a huge relief.

High Conscientiousness

Research shows that many people with OCD are highly conscientious (Coles et al., 2003). They care deeply about doing the right thing, living by their values, and not causing harm.

This conscientiousness is often a strength — making someone reliable, diligent, and thoughtful. But in OCD it can become a double-edged sword:

• The drive to “do the right thing” makes intrusive doubts feel intolerable.

• Even a tiny possibility of harm feels catastrophic.

• Responsibility feels magnified.
  

Example (Harm OCD): A fleeting thought of pushing someone at a train station spirals into hours of worry: “Why did I think that? Does it mean I want to act on it?”

Example (SO-OCD): Noticing someone attractive triggers self-analysis: “Does this mean my relationship is a lie? Am I deceiving myself?”

This isn’t recklessness — it’s over-responsibility turned against itself.

Ego-Dystonic Thoughts

Another hallmark of Pure O is that intrusive thoughts are ego-dystonic — they clash painfully with a person’s values and identity.

• A gentle person may be tormented by violent images.

• A loving partner may be plagued by doubts about attraction.

• A devoted parent may be horrified by unwanted sexual thoughts.
  

Because the thoughts are the opposite of what the person wants, they feel especially threatening. People often fear:

• “If I had this thought, it must mean something about me.”

• “The fact I’m disturbed by it proves it matters.”
  

In OCD therapy we remind clients: it’s because the thoughts are ego-dystonic that they stick. People who want to cause harm don’t obsess about the possibility of being harmful.

Thought-Action Fusion

A third feature is thought-action fusion (TAF) — the mistaken belief that thinking something makes it more likely to happen, or as bad as doing it (Shafran et al., 1996).

Likelihood TAF: “If I think it, I’ll make it happen.”

Moral TAF: “If I think it, it’s as bad as doing it.”

Thought-event fusion: “If I think it, I’ll notice signs it’s true.”

Examples:

Contamination OCD: “If I imagine spreading germs, I increase the risk.”

• Harm OCD: “If I think about stabbing someone, it’s as bad as doing it.”

• Somatic OCD: “If I imagine forgetting how to swallow, I might cause myself to choke.”

TAF makes thoughts “sticky” — rather than dismissing them as mental noise, people feel compelled to neutralise, check, or reassure.

Cognitive Factors in the Classic CBT Model

Alongside these features, classic CBT research (Salkovskis, Rachman) highlights several cognitive tendencies common in OCD:

• Inflated responsibility – feeling you must prevent harm and are accountable if you don’t.

• Over-importance of thoughts – believing that having a thought makes it significant or revealing.

• Perfectionism – needing certainty or flawless performance.

• Intolerance of uncertainty – finding any doubt unbearable.

  
  

These don’t cause OCD alone, but they tighten the loop between obsession and compulsion, especially when combined with conscientiousness, ego-dystonicity, and thought-action fusion.

Why Pure O Feels So Convincing

• Conscientiousness magnifies responsibility.

• Ego-dystonic thoughts clash with core values.

• Thought-action fusion turns imagination into danger.

• Classic CBT factors (responsibility, over-importance of thoughts, perfectionism, intolerance of uncertainty) amplify the cycle.
  

Together, these create a reasoning trap where intrusive thoughts feel not just disturbing but meaningful.

How Therapy Helps

When searching for OCD therapy in Edinburgh or online, people with Pure O often fear:

• “A therapist will think I’m dangerous.”

• “ERP won’t work — how can I expose myself to thoughts?”
  

The good news: several evidence-based approaches exist.

Exposure and Response Prevention (ERP)

ERP is the gold standard for OCD. It means facing intrusive thoughts or triggers while resisting compulsions. Over time, anxiety fades and thoughts lose their power.

For Pure O, ERP often uses imaginal exposure (writing or recording feared thoughts), looped audio scripts, and preventing covert rituals such as mental checking or neutralising.

ERP is highly effective, but it can feel intense — and drop-out or non-completion can occur if exposures feel too overwhelming.

Inference-Based Cognitive Therapy (i-CBT)

i-CBT takes a cognitive-first approach. Instead of exposure, it focuses on how doubt is built in the first place.

Clients learn to spot when they are reasoning from possibility rather than perception — for example: “What do my senses tell me right now?” They also practise recognising when they rely on indirect or hearsay information that inflates doubt.

For many with Pure O, i-CBT feels validating because it addresses the doubt mechanism directly.

Acceptance and Commitment Therapy (ACT)

ACT helps people change their relationship with intrusive thoughts. Rather than suppressing or debating them, ACT builds skills in:

• Defusion: noticing “I’m having the thought that…” instead of “This thought is true.”

• Acceptance: allowing experiences to be present without struggle.

• Values and committed action: choosing steps that matter, even while doubts arise.

Example: Someone with Harm OCD notices, “What if I hurt someone?”. In ACT they might reframe: “I’m having the thought that I could hurt someone.” Then they take a values-led step — such as showing care to loved ones — even with the thought present.

UK Guidance and Medication

In the UK, NICE guidelines recommend CBT with ERP as the first-line treatment for OCD. SSRIs may also be offered via GP or psychiatry, particularly when symptoms are severe or therapy access is limited. Many people benefit from a combined approach.

Safeguarding and Reassurance

Where intrusive thoughts involve harm or sexual themes, clinicians always carry out routine risk assessments. In OCD these thoughts are typically unwanted and ego-dystonic — the opposite of intention. Knowing this can reduce shame and make it easier to seek help.

In clinical practice, clients have been able to share their most troubling intrusive thoughts in a safe space, often things they have never been able to tell anyone before. By understanding the mechanisms of OCD, clients can gradually see the content of these thoughts as being part of the disorder and not their feared identity.

A Practical Step

When an intrusive thought shows up, try:

1. Notice – “This is an intrusive thought, not a fact.”

2. Name the process – Is it TAF, responsibility, perfectionism, or uncertainty etc?

3. Next step – Ground in your senses, and take a small action aligned with your values, not as a compulsion but more a focus on what is in your actual life.
   

You don’t need to argue with the thought. Just shifting your response begins to loosen its hold.

Ready to Take the Next Step?

If these patterns sound familiar, OCD therapy can help. Whether you’re in Edinburgh or looking for online support, therapy offers a safe and compassionate way to untangle intrusive thoughts.

The first step is a brief pre-intake call where we can talk about your experience and see if therapy feels right for you.

Book A Free Consultation >

References

• O’Connor, K. & Aardema, F. (2012). Clinician’s Handbook for Obsessive-Compulsive Disorder: Inference-Based Therapy. Wiley.

• Coles, M. E., Frost, R. O., Heimberg, R. G., & Rhéaume, J. (2003). Responsibility in OCD: An Examination of Conscientiousness. Journal of Anxiety Disorders.

• Shafran, R., Thordarson, D. S., & Rachman, S. (1996). Thought–action fusion in OCD. Journal of Anxiety Disorders.

• Hayes, S. C., Strosahl, K. D., & Wilson, K. G. (2012). Acceptance and Commitment Therapy: The Process and Practice of Mindful Change.

• NICE (2005/updated). Obsessive-compulsive disorder and body dysmorphic disorder: treatment guidelines.