For adults

Harm OCD: violent intrusive thoughts

Harm OCD is OCD in which the obsession is the fear of hurting someone, or of having already hurt someone without realising. The thoughts are violent, they horrify the person having them, and they are usually aimed at the people that person loves most.

The forms it usually takes

Most people have had a flash of something violent pass through their mind, such as pushing someone off a platform, and dismissed it. In harm OCD the thought sticks, because it is read as a warning about what you might be capable of, and the effort to make sure it never happens becomes the problem. You may recognise more than one of the forms below.

Knives, kitchens and sharp objects

Someone is chopping onions with their partner in the room and gets a sudden picture of turning round with the knife. From then on they cook only when alone, hide the knife block in a cupboard and avoid scissors and razors, or put the knife down the moment someone walks in.

Driving and the fear of a hit-and-run

The car hits a pothole, or a cyclist passes close to the wing mirror, and a doubt arrives that it might have been a person. People drive the route again, inspect the bumper, check local news for accidents and occasionally phone hospitals or the police. Others fear swerving into a pedestrian on purpose, and avoid busy roads or stop driving altogether.

Harming the people you love

The most distressing version targets a partner, a parent or a child, with images of strangling, stabbing or pushing, or a doubt about whether you might snap one day. People stop being alone with the person, avoid hugging them, check their own mood for signs of anger, and confess the thoughts to be told they are safe. In teenagers it may be aimed at a parent or sibling and kept secret, and may show only as sudden avoidance of the kitchen or of being home alone with a younger brother or sister.

How OCD differs from genuine risk

I assess risk, as any clinician should. In harm OCD the thoughts are unwanted and at odds with what the person values, and they lead to fear, avoidance, checking and reassurance-seeking. Where there is genuine risk of violence, there may be a history of violence, anger or a grievance against a particular person, the thoughts may feel satisfying or justified, and there may be planning. If thoughts of harm come with voices telling you to act, a sense that your thoughts are being controlled from outside, or heavy drinking or drug use, that needs a different assessment, and I would ask you to speak to your GP the same day.

Why hiding the knives backfires

Every protective step brings relief, which is why it gets repeated. Removing the knives lowers the anxiety that evening, and it also teaches you that you are someone from whom knives need to be kept and that nothing happened only because you took precautions, so the next time you see a knife the fear is stronger. Checking has a further cost. In experiments by van den Hout and Kindt (2003), repeated checking left people’s memory of what they had checked less vivid and less detailed, and they trusted it less, even though the memory was no less accurate, so driving a route again leaves you more doubtful. Scanning yourself for anger works in a similar way, because ordinary irritation, once you look for it, feels like a step towards losing control.

The harm OCD loop

1. Trigger: Chopping vegetables with your partner nearby
2. Obsession: An image of stabbing them. What if I want to?
3. Feeling: Horror, anxiety, and doubt about who you are
4. Compulsion: Hiding the knives, reviewing the thought, asking if you are safe
5. Relief, for now: Reassured for an hour, then the image returns
6. Then back to the first step, and the loop runs again.
7. Other situations that now set it off too: Bath time with your child, driving past a school, A news report, being alone with a relative.

Where treatment steps in. You put the knives back, stay in the kitchen with the thought present, and stop the reviewing and asking. You learn that you can carry the thought and the doubt without acting on either.

New triggers. Over time, more situations become linked to the trigger and start the loop off too.

How I treat harm OCD

The treatment is exposure and response prevention (ERP) within cognitive behavioural therapy. In plain terms, you approach the thoughts and situations you have been avoiding, on purpose, and stop doing the checks. We first map every compulsion and every place and object you now avoid, and build a list of steps which you choose from, starting with one that feels manageable. The main thing you learn is that you can have the thought and the anxiety that comes with it and carry on with ordinary life without needing to be certain first.

Early steps might be writing the thought down in plain words, saying it aloud in a session and putting the knife block back on the worktop. Later ones might be chopping vegetables with your partner in the kitchen while the thought is present, driving a busy route without going back, and listening to a short recorded script of the feared scene. The list is not a fixed sequence, because practice that mixes easier and harder steps tends to hold up better. Your partner or family may be asked to change how they answer when you ask whether you are safe, and I can help you explain that to them. I give you an estimate of how long it is likely to take by the end of the first session.

What the research says, and what it does not

In a survey of 360 psychologists given short case descriptions, 31.5 per cent misidentified the description of aggressive obsessions (Glazier and colleagues, 2013), so being misread by a professional is not unusual. ERP is the psychological treatment NICE recommends for OCD, and trials of it include people with harm obsessions, but few look at harm obsessions separately from other OCD. It is also not known why one person’s OCD settles on violence and another’s on contamination.

Sources

• Veale, D., Freeston, M., Krebs, G., Heyman, I., & Salkovskis, P. (2009). Risk assessment and management in obsessive-compulsive disorder. Advances in Psychiatric Treatment, 15(5), 332-343. cambridge.org (opens in a new tab)
• Glazier, K., Calixte, R. M., Rothschild, R., & Pinto, A. (2013). High rates of OCD symptom misidentification by mental health professionals. Annals of Clinical Psychiatry, 25(3), 201-209. journals.sagepub.com (opens in a new tab)
• van den Hout, M., & Kindt, M. (2003). Repeated checking causes memory distrust. Behaviour Research and Therapy, 41(3), 301-316. pubmed.ncbi.nlm.nih.gov (opens in a new tab)
• National Institute for Health and Care Excellence. Obsessive-compulsive disorder and body dysmorphic disorder: treatment. Clinical guideline CG31 (2005; an update is in development). nice.org.uk/guidance/cg31 (opens in a new tab)

Common questions

Written by Dr Daniel O’Rourke, PhD, ABPP, CPsychol, HCPC-registered Clinical Psychologist Last reviewed: September 2026