Written by Clinical Psychology Registrar James Clancy
In this blog we will explore why intrusive thoughts feel so convincing in OCD, why that doesn’t mean they’re true or dangerous, and how therapeutic interventions can change how and if you engage with them.
Intrusive Thoughts and OCD
Intrusive thoughts can be very upsetting for people living with OCD (obsessive-compulsive disorder). You might be making a sandwich, stopped at a red light in your car, or scrolling your phone when a sudden, unwanted thought or image pops into your awareness that feels wrong, uncomfortable, and just “not who you are.” Despite this, the thought can feel very urgent and factual.
Intrusive Thoughts are Common
Research has found that 80–90% of people experience random, unwanted intrusive thoughts, including thoughts about harm, sex, germs, or blasphemy. The content of these thoughts often looks very similar to those people with OCD describe.
The difference for people living with OCD is not the thoughts themselves, but the way the individual engages with those thoughts. Cognitive models suggest that intrusive thoughts become obsessions when they are believed to be meaningful, dangerous, urgent, and important, rather than random intrusions.
Appraisals: When a Thought Turns into an Obsession
It is theorised that the “factuality” of intrusive thoughts comes from how the brain appraises them.
Common appraisals include:
- “Having this thought means I’m a bad or dangerous person.”
- “If I think it, it might happen.”
- “If I don’t get certainty about this, something bad may happen and it would be my fault.”
OCD intrusive thoughts may become obsessions when they are linked to an inflated sense of personal responsibility. For example, a thought related to harm doesn’t feel real because it is a hidden desire, but because the person feels deeply responsible for even the possibility of the harm.
Thought–Action Fusion: When Thinking Feels Like Doing
Intrusive thoughts may feel real due to the so called thought–action fusion (TAF), where people living with OCD may believe having a thought can lead to the outcome (Moral) or have an influence (Likelihood).
Studies link these kinds of beliefs with more distress and more severe OCD symptoms. If your OCD brain is convinced that thoughts like “What if I hurt someone?” is similar to hurting them, or increases the risk, of course the thought feels dangerous, urgent, and important.
Intolerance of Uncertainty and the Need to Know
OCD brains struggle with doubt and will look for ways to reduce uncertainty. People living with OCD often feel they must know, with 100% certainty, that they would not act on an intrusive thought or that nothing bad will happen.
This intolerance of uncertainty can make intrusive thoughts seem real because:
- Any doubt may be treated as a serious warning.
- A lack of evidence can feel like the presence of risk.
- The cycling review of memories, values, beliefs, and feelings to try to “check” the validity of the thought.
The uncertainty and doubt may reduce; however, the original thought may not have been satisfactory resolved, causing it to return and persist.
Why Trying to “Figure It Out” Makes It Worse
Due to the distress that people living with OCD, it makes sense that they may try to cope with intrusive thoughts by:
- Analysing why they had the thought.
- Checking whether they “really” want it.
- Reviewing memories to see whether they’ve ever done anything similar.
- Seeking reassurance from others.
Over time, this checking and reassurance seeking may actually help to maintain engagement with the thought, which makes it seem factual and important.
Therapeutic Intervention: Changing the Relationship with Thoughts
There is help for people living with OCD and impacted by intrusive thoughts. Cognitive-behavioural therapy (CBT) with Exposure and Response Prevention (ERP) have been found to assist in targeting intrusive thoughts by:
- Challenging unhelpful beliefs about responsibility, thought–action fusion, and uncertainty.
- Reducing rituals, reassurance seeking, and mental checking.
- Gradually becoming exposed to feared thoughts, feelings, and situations.
CBT with ERP is the ‘Gold standard’, first-line treatment for OCD. Over time, people living with OCD may change how they engage with thoughts, to the extent that they may see intrusive thoughts as “just thoughts”, rather than signals of danger or evidence about who they are.
What This Means for You
If your intrusive thoughts feel disturbingly real, it doesn’t mean you secretly want them or are more likely to act on them. Research suggests:
- Intrusive thoughts are common.
- In OCD, they may feel real because of how they are appraised.
- With a strong therapeutic alliance, you can learn to respond differently so that the thoughts lose their intensity and power.
References
Abramowitz, J. S., Deacon, B. J., & Whiteside, S. P. (2019). Exposure therapy for anxiety: Principles and practice (2nd ed.). Guilford Press.
Australian Psychological Society. (2023). Evidence-based psychological approaches for obsessive–compulsive disorder. Australian Psychological Society.
Overview page: https://psychology.org.au/for-the-public/psychology-topics/obsessive-compulsive-disorder
Clark, D. A. (2005), Intrusive thoughts in clinical disorders: Theory, research, and treatment. Guilford Press.
Janardhan Reddy, Y. C., Sundar, A. S., Narayanaswamy, J. C., & Math, S. B. (2017). Clinical practice guidelines for Obsessive-Compulsive Disorder. Indian Journal of Psychiatry, 59(Suppl 1), S74–S90. https://doi.org/10.4103/0019-5545.196976
Jürgens, C., Rupp, C., Doebler, P., Andor, F., & Buhlmann, U. (2019). Metacognition in obsessive-compulsive disorder symptom dimensions: The role of fusion beliefs, beliefs about rituals, and stop signals. Journal of Obsessive-Compulsive and Related Disorders, 21, 102-111. https://doi.org/10.1016/j.jocrd.2019.03.002
Kalanthroff, E., & Wheaton, M. G. (2022). An Integrative Model for Understanding Obsessive-Compulsive Disorder: Merging Cognitive Behavioral Theory with Insights from Clinical Neuroscience. Journal of clinical medicine, 11(24), 7379. https://doi.org/10.3390/jcm11247379
Olatunji, B. O., Davis, M. L., Powers, M. B., & Smits, J. A. J. (2013). Cognitive-behavioral therapy for obsessive–compulsive disorder: A meta-analysis of treatment outcome and moderators. Journal of Psychiatric Research, 47(1), 33–41. https://doi.org/10.1016/j.jpsychires.2012.08.020
Vervliet, B., Craske, M. G., & Hermans, D. (2013). Fear extinction and relapse: State of the art. Annual Review of Clinical Psychology, 9, 215–248. https://doi.org/10.1146/annurev-clinpsy-050212-185542
