Intrusive thoughts and OCD: help, and what actually works

What are intrusive thoughts?

Intrusive thoughts are unwanted thoughts, images or urges that arrive uninvited and clash with what you value. Almost everyone has them. In OCD they are treated as meaningful and dangerous, which triggers intense distress and compulsions to cancel them out. Help focuses on changing your relationship with the thoughts rather than removing them.

Everyone has intrusive thoughts

Standing on the platform at Britomart and picturing yourself stepping off the edge. Holding a newborn and thinking "what if I dropped her?" Sitting at a tangi or in a church service and a crude word flashes through your mind. Driving over the Harbour Bridge and wondering what would happen if you turned the wheel.

If any of those are familiar, you're in the majority. In a study of 777 university students across 13 countries on six continents, 93.6% reported at least one unwanted intrusive thought in the previous three months. Doubting thoughts ("did I lock it?") were the most common type; repugnant thoughts about harm, sex or blasphemy were less common but still widely reported. Intrusive thoughts are a feature of normal cognition, not a symptom.

What separates a person with OCD from everyone else is not the thought. It's what happens next.

Why intrusive thoughts get stuck in OCD

Most people notice an odd thought, find it slightly unpleasant, and move on. The thought carries no more weight than a song stuck in your head. In OCD the thought is appraised differently: it feels significant, revealing, dangerous. "Why would I think that unless part of me wants it?" "Thinking it makes it more likely." "A good person wouldn't have that thought." "I have to be certain."

Once the thought matters that much, your body treats it as a threat. Anxiety, guilt or disgust surge, and you do something to make it stop: push the thought away, check yourself for signs you're a bad person, replay the moment to prove you didn't do anything, ask someone whether you're normal. The relief is immediate and the lesson is learned: that thought was dangerous, and the ritual saved you. The thought comes back carrying more charge.

This is why OCD so often targets what you care about most. Someone who loves their children gets harm thoughts about their children. Someone devoted to their faith gets blasphemous thoughts. A thought that didn't clash with your values wouldn't frighten you, and a thought that didn't frighten you wouldn't stick. The content of your intrusive thoughts says something about your values, not your intentions.

What intrusive thoughts in OCD can look like

People rarely say these out loud, so here are the themes psychologists hear every week. They are described plainly because the shame around them is part of what keeps OCD going.

• Harm. Images of stabbing a partner while cooking dinner, pushing a stranger into traffic on Queen Street, or hurting your baby during a nappy change. Often with a sudden "urge" that feels real. See harm OCD.
• Sexual. Unwanted sexual thoughts about children, family members or strangers, or doubts about your sexual orientation that contradict your experience. These are among the most distressing and least disclosed obsessions, and they respond to the same ERP approach as any other OCD theme.
• Religious and moral. Swearing at God, offensive images during karakia or prayer, fear of having sinned without knowing, endless reviewing of whether you lied or cheated. See scrupulosity.
• "What if" doubts. Did I hit a cyclist on the way home? Did I turn the heater off? Did I say something awful at the work drinks? What if I don't actually love my partner? See relationship OCD.
• Existential or "real event". Looping on whether reality is real, or on something you actually did years ago, replaying it for proof you're not a terrible person.

Many people with these thoughts have few visible rituals; the compulsions are mental. That pattern is often called "Pure O", and it's OCD like any other.

Book a session How booking works →

A thought is not an intention

This is the distinction OCD blurs and treatment restores. An intention is something you want, plan and move towards. An obsession is something you don't want, are horrified by, and organise your life to avoid. Clinicians who specialise in OCD risk assessment describe the intrusive thoughts of people with OCD as usually distinguishable from the thoughts of people who intend harm: in OCD the thought is ego-dystonic (against your sense of who you are), it produces guilt and fear rather than pleasure, and the person takes elaborate steps to prevent it ever happening.

There's a cruel irony here. Checking "do I actually want this?" is itself a compulsion, and the harder you look for proof you're safe, the more "evidence" OCD finds to doubt. Treatment doesn't work by proving you're a good person. It works by helping you stop needing the proof.

If you tell a psychologist about these thoughts, they will not assume you are dangerous. They may ask some routine questions about risk, as they would with anyone, because they're careful, not because the content of your thoughts alarms them.

What not to do, and why it's so tempting

• Don't try to suppress the thought. A meta-analysis of controlled studies found that trying not to think about something produces a rebound: the thought comes back more, not less. Every "stop thinking that" is a rehearsal.
• Don't seek reassurance. Asking "you don't think I'm a paedophile, do you?" or "would you tell me if I were dangerous?" brings relief for an hour and strengthens the loop. Research shows people with OCD seek reassurance more often and more intensely than people without it, including reassuring themselves. Partners and whānau are usually relieved to be given permission to stop answering.
• Don't Google it. Searching "intrusive thoughts about hurting my baby" at midnight is checking with extra steps. You'll find pages like this one that say the thoughts are common, feel calmer for a while, and need to search again tomorrow.
• Don't try to solve it. Analysing where the thought came from, what it means and whether you've always been like this is a mental compulsion. The question has no answer that OCD will accept.
• Don't quietly restructure your life around it. Avoiding the knife drawer, bath time or the motorway reduces anxiety today and confirms the danger for tomorrow.

None of this is a criticism. Every one of these responses is the obvious, sensible thing to do with a thought that feels like a threat. They just happen to feed OCD.

How ERP and cognitive approaches help

The treatment with the strongest evidence is exposure and response prevention (ERP), recommended by NICE, the American Psychiatric Association and the International OCD Foundation. For intrusive thoughts specifically, it looks like this.

Exposure to the thought itself. Rather than pushing it away, you deliberately bring it on: writing the thought out in full, recording a short script of the feared scenario and listening to it daily, saying the word, looking at the photo, standing in the kitchen with the knife while your partner is there. The aim is to let the thought be present, in detail, without doing anything about it.

Response prevention for the mental rituals. You learn to spot reviewing, checking your feelings, reassuring yourself and neutralising, and to leave the question open. "Maybe I am, maybe I'm not" becomes a practised response rather than a terrifying one.

Cognitive work on the appraisals. You and your psychologist test the beliefs that give the thoughts their weight: that thinking something makes it more likely, that you're responsible for every thought you have, that a good person's mind would be clean. Acceptance-based approaches such as ACT add practice at making room for a thought while getting on with your day.

Done online, this work happens where the thoughts show up: your kitchen, your baby's room, your car. A full course is typically 12 to 20 sessions, and you can read the step-by-step process on our ERP therapy page. Psychologists who work with OCD hear thoughts like these often, and you won't be the first person to say yours out loud.

When to get more help, and where

Intrusive thoughts alone are not an emergency, however horrible their content. Two things change that. If the thought has stopped frightening you and started to feel like something you want to do, or if OCD has worn you down to the point of thinking about ending your life, talk to someone today: your GP, or 1737 (free call or text, 24/7). If you or someone else is in immediate danger, call 111. Mindwell is not a crisis service.

Intrusive thoughts also show up outside OCD: as flashbacks in PTSD, as ruminations in depression, or as worries in generalised anxiety. Treatment differs, so if you're not sure what you're dealing with, an OCD assessment is the right first step. You can book directly with a Mindwell psychologist, no referral needed, for $199 + GST ($228.85 incl. GST) per session.

Related support: OCD treatment · Pure O · Harm OCD · ERP therapy