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Intrusive Thoughts: Why You Get Them and How to Stop Them Taking Over

Intrusive thoughts are unwanted, upsetting thoughts, images or urges, often about harm, sex, illness or doing something out of character. Almost everyone has them, and having one doesn’t mean you want it or will act on it.

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Last updated: October 2026

Intrusive thoughts are unwanted, upsetting thoughts, images or urges, often about harm, sex, illness or doing something out of character. Almost everyone has them, and having one doesn’t mean you want it or will act on it. They become a problem when they’re frequent and distressing, which can be a sign of anxiety or OCD.

Below: common examples, why they happen, when they might be OCD, how to stop them taking over, and where to get help.

Remember: a thought is not an action or a wish. The fact that a thought upsets you usually shows it goes against your values.

Examples of intrusive thoughts

The NHS notes that almost everyone has unpleasant or unwanted thoughts at some point, including sudden violent or offensive images. Studies of people without OCD have found the same kinds of thoughts are very common. Typical examples:

Type Example
Harm “What if I pushed someone onto the train tracks?” or an image of hurting a loved one
Accidents “What if I left the cooker on and the house burns down?”
Contamination “What if I’ve caught something and pass it to my children?”
Health “What if this headache is a brain tumour?” See health anxiety
Sexual Unwanted sexual thoughts or images that feel shocking or wrong
Relationships “What if I don’t really love my partner?”
Religion or morality Blasphemous thoughts, or fear of being a bad person
New parents Sudden images of the baby being harmed, which are very common after birth

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Why do intrusive thoughts happen?

Your brain produces thousands of thoughts a day, many random. Intrusive thoughts are part of that background noise. They tend to show up more when you’re:

The thoughts that stick are usually the ones that clash most with what you care about. A loving parent gets thoughts about harming their child precisely because it horrifies them.

Intrusive thoughts and OCD

Obsessive compulsive disorder (OCD) has three parts, according to the NHS:

  1. Obsessions: unwanted, intrusive thoughts, images or urges that keep coming back.
  2. Emotions: intense anxiety or distress.
  3. Compulsions: repeated behaviours or mental acts to ease the anxiety, such as checking, washing, seeking reassurance, praying, counting or mentally “undoing” the thought.

The compulsion brings brief relief, but the anxiety returns and the cycle repeats. Some people have mostly mental compulsions, which is sometimes called “Pure O”. If intrusive thoughts and the things you do to neutralise them take up a lot of time or interfere with your life, it may be OCD. The good news is that OCD is very treatable. See how to stop overthinking.

Why fighting them makes them worse

Trying hard not to think something tends to make it come back more. Try not to think of a pink elephant for 30 seconds and you’ll see. When you treat an intrusive thought as dangerous, by arguing with it, checking or seeking reassurance, your brain learns it’s important and serves it up more often.

What helps is changing your relationship with the thought, not getting rid of it.

Intrusive thoughts after having a baby

Sudden, frightening thoughts or images of something bad happening to your baby are extremely common in new parents, both mums and dads. You might picture dropping the baby, them being hurt, or even yourself causing harm, and feel horrified. These thoughts are usually your brain’s over-protective alarm system working overtime, fuelled by exhaustion and the huge responsibility of a newborn.

  • Having the thoughts doesn’t mean you’re a bad parent or a danger to your baby.
  • Avoiding your baby, or things like bathing them, tends to make the fear stronger.
  • Talk to your health visitor, midwife or GP. They hear this often and can offer support.
  • If the thoughts are constant, or come with low mood or anxiety, it may be postnatal anxiety, depression or perinatal OCD, which are all treatable.

How to stop intrusive thoughts taking over

  1. Name it. “That’s an intrusive thought.” Labelling it creates distance.
  2. Don’t argue or analyse. Let it be there without trying to prove it wrong.
  3. Let it pass like a car going by. Notice it, then return to what you were doing. See mindfulness for beginners.
  4. Reduce reassurance-seeking and checking, a little at a time.
  5. Don’t avoid things because of the thought, such as knives or holding the baby. Avoidance keeps the fear going.
  6. Calm your body when anxiety spikes. See box breathing and grounding techniques.
  7. Look after the basics: sleep, exercise, less caffeine and alcohol. See does caffeine cause anxiety?
  8. Talk about it with someone you trust, or a professional. Saying it out loud often takes away its power.

A calming evening routine can help when thoughts feel louder at night. Our Magnesium Glycinate Sleep Complex is a caffeine-free bedtime drink with L-theanine, and magnesium contributes to normal psychological function. Some people take our Flow CBD Oil as part of their daily routine. CBD is a food supplement, not a treatment for OCD or anxiety. The FSA’s 10mg a day figure for CBD is precautionary advice rather than a legal limit, set while longer-term safety research continues. At Evopure we think it is a very cautious figure, and many adults use more. If you go above it, increase slowly, and check with your GP or pharmacist first if you take any medication. See anxiety at night.

When to get help

See a GP or refer yourself to NHS Talking Therapies if intrusive thoughts are frequent, distressing, take up a lot of your time or stop you doing things. The main treatment for OCD is CBT with exposure and response prevention (ERP), and sometimes medicine. OCD-UK also offers support. If you’re a new parent with distressing thoughts, tell your health visitor or GP. These thoughts are common and you won’t be judged.

If you’re having thoughts of harming yourself and feel you might act on them, that’s different. Call 999, NHS 111 or Samaritans on 116 123. See how to deal with anxiety.

If you’ve wondered whether CBD has a role, see what the research says on CBD and OCD.

Sources 4

  1. NHS. Symptoms of obsessive compulsive disorder (OCD).
  2. Purdon C, Clark DA (1993). Obsessive intrusive thoughts in nonclinical subjects. Part I. Behaviour Research and Therapy.
  3. Julien D et al (2007). Intrusive thoughts, obsessions, and appraisals in obsessive-compulsive disorder: a critical review. Clinical Psychology Review.
  4. OCD-UK. ocduk.org.

This guide is general information, not medical advice. Evopure makes the Magnesium Glycinate Sleep Complex and Flow CBD Oil.

Written by

Co-founder, Evopure

Martin co-founded Evopure and writes about sleep, stress and recovery. Our articles are general information, not medical advice.

Questions, answered

Yes. Almost everyone has unwanted, upsetting thoughts sometimes, including violent or sexual ones. Having them doesn't mean you want them or will act on them.

Don't fight or analyse them. Label them as intrusive thoughts, let them pass, cut back on checking and reassurance, and look after sleep and stress.

Not on their own. It may be OCD if the thoughts are frequent and distressing and you feel driven to do things, such as checking or seeking reassurance, to ease the anxiety.

Yes. Stress, anxiety, tiredness and hormonal changes can all make intrusive thoughts more frequent and harder to let go.

Self-help can help with milder thoughts. For OCD, CBT with exposure and response prevention (ERP) is the main treatment, available through NHS Talking Therapies.

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