Intrusive Thoughts: When They Are Normal and When It Is Obsessive-Compulsive Disorder

What Are Intrusive Thoughts?

Intrusive thoughts are involuntary thoughts, images or impulses that arise against your will and feel alien. It might be a sudden thought of pushing someone on a train platform, an image of dropping a baby, a doubt about whether you turned off the iron, a blasphemous thought during prayer or an indecent image at the wrong moment. Most people notice such episodes at least occasionally.

For most people, such a thought appears, causes mild puzzlement and then goes away, because they do not attach any importance to it. The brain constantly generates random associations, including absurd and frightening ones. This is a by-product of how it works, not a reflection of a person's character or intentions. The problem starts not with the thought itself, but with how the person judges it and what they do with it.

Why the thoughts can be so frightening

Intrusive thoughts most often concern what is especially precious or forbidden to the person: the safety of loved ones, religion, sexuality, morality, health. That is exactly why they hit so hard. A caring parent is horrified by a thought of harming their child, and a believer by a blasphemous thought.

The suppression effect

If you tell yourself "don't think about it," the thought comes back more often. This is a well-known psychological effect of suppression: the more effort you put into chasing a thought away, the more closely your brain tracks it and the more persistent it becomes.

How Normal Intrusive Thoughts Differ From OCD

According to ICD-11 and DSM-5, obsessive-compulsive disorder is characterized by obsessions, compulsions or both. Obsessions are recurring intrusive thoughts, images or urges that are experienced as unwanted and cause marked anxiety. Compulsions are repetitive actions or mental rituals that a person feels driven to perform in response to an obsession in order to reduce anxiety or prevent an imagined disaster.

The key differences from normal experience are time, distress and impact on life. In OCD, obsessions and compulsions take up a lot of time, usually more than an hour a day, cause severe distress or interfere with work, study and relationships. The person usually understands that the thoughts are excessive but cannot stop. In ICD-10, this disorder is coded F42.

• The thought causes intense anxiety rather than mild puzzlement
• The same themes come back almost every day
• Rituals have appeared: checking, washing, counting, rearranging, repeating words
• You mentally "cancel out" a bad thought with a good one
• You often ask loved ones to reassure you that everything is fine
• You avoid situations, objects or people that trigger the thoughts
• Thoughts and rituals take up more than an hour a day

Types of Intrusive Thoughts in OCD

OCD shows up in different ways, and in the same person the themes can change over time. The best-known forms are fears of dirt and contamination with repeated hand washing, doubts with checking of locks, the stove and electrical appliances, and a need for symmetry and order. But many forms of OCD are almost invisible from the outside, because the rituals are performed in the mind.

Mental rituals include analyzing, rechecking memories, praying, counting, repeating "correct" phrases and trying to prove to yourself that you are not a bad person. On the outside the person looks calm, but inside they are locked in an exhausting argument with their own thoughts. This form is sometimes called "Pure O" (purely obsessional OCD), although hidden compulsions are almost always present.

Aggressive (harm) obsessions

Frightening thoughts of harming yourself or others, for example hitting a loved one, picking up a knife or jumping. Importantly, in OCD these thoughts cause horror and disgust, and the person does everything possible to avoid situations where they could act on them. This is the opposite of a real intention.

Religious and moral obsessions

Fear of sinning, offending something sacred, being a bad person or lying. The person may confess over and over, ask for forgiveness and keep checking whether they were honest. This form is called scrupulosity.

Relationship and sexual obsessions

Doubts about your feelings for your partner or your own sexual orientation, and unwanted images of a sexual nature. The thoughts are accompanied by constant self-checking ("what did I feel just now?"), which only increases the anxiety.

Are Intrusive Thoughts About Causing Harm Dangerous?

This is the most common fear among people with harm obsessions: "If I think about it, it means I could do it." In OCD, this is not the case. The thoughts are ego-dystonic, meaning they contradict the person's values and desires. That is exactly why they are so tormenting. People with OCD are, as a rule, extremely careful and do not carry out the actions they fear.

The situation is entirely different when thoughts of violence come with desire, a plan, anger or pleasure rather than horror, or when a person hears voices telling them to cause harm. This is not typical of OCD and requires an urgent psychiatric assessment. If you are unsure which category your thoughts fall into, discuss it with a specialist: medical confidentiality is protected by law, and such a conversation is safe.

What to Do If Intrusive Thoughts Will Not Leave You Alone

The first rule is not to argue with the thought and not to try to push it out. Notice it and label it, "this is an intrusive thought," without judging or analyzing it. Let it be there like background noise and get back to what you were doing. At first this causes anxiety, but over time the thought loses its power because it is no longer being reinforced.

The second rule is to gradually cut down on rituals. Every check, rewash or search for reassurance lowers anxiety for a short time but teaches the brain that the danger was real. Postpone the ritual for a few minutes, then for longer. Doing this on your own helps with mild symptoms, but with pronounced OCD it is better done under the guidance of a psychotherapist.

1. Label the thought as intrusive without getting into an argument with it
2. Do not seek reassurance from loved ones or on the internet
3. Postpone rituals, gradually lengthening the delay
4. Do not avoid situations that trigger the thoughts
5. Bring your attention back to the task at hand
6. Reduce overall stress: sleep, physical activity, no alcohol

How OCD Is Treated

The method with the strongest evidence base is cognitive behavioral therapy with exposure and response prevention (ERP). Under a psychotherapist's guidance, the person gradually faces what triggers the obsessions and learns not to perform the ritual. Anxiety rises at first, then subsides on its own, and the brain rewires its response. The guidelines of NICE and the American Psychiatric Association classify this approach as first-line treatment.

For moderate and severe OCD, medication is often added to psychotherapy. Antidepressants from certain classes are used; in OCD the effect develops more slowly than in depression, and treatment is usually long-term. The medication and regimen are chosen only by a psychiatrist. It is important not to stop treatment on your own at the first signs of improvement.

Treating OCD online

Diagnosis, choice of therapy and CBT sessions with exposure work well by video, and sometimes this is even more convenient: exercises can be done where the symptoms arise, at home, in the kitchen or at the front door. At Psychiatry Online, you can book an anonymous appointment with a psychiatrist and psychotherapist from any city in Kazakhstan.

When to see a doctor

• Intrusive thoughts and rituals take up more than an hour a day
• You avoid knives, children, transport or other situations because of frightening thoughts
• Your loved ones are tired of answering your repeated questions and requests to confirm that everything is fine
• Because of checking and washing, you are late, cannot get your work done or damage the skin on your hands
• Low mood and hopelessness have joined the obsessions
• Thoughts of harm come with desire, a plan or voices: an urgent assessment is needed

Questions and answers

Reviewed by

Pavel Kornilov, MDPsychiatrist

Depression, anxiety disorders, OCD, bipolar disorder; online medication selection and adjustment.