Intrusive thoughts appear involuntarily and can be unpleasant, absurd, or contrary to our values. Having them does not necessarily mean wanting to carry them out. The problem usually begins when we try to eliminate them, constantly interpret them, or seek absolute certainty about what they mean.
You are driving and, for a second, the image of sharply turning the steering wheel appears in your head. You are holding a baby and the thought crosses your mind that you could harm them. You leave the house and, although you remember having locked the door, a sudden doubt arises: "What if I actually left it open?" The thought appears uninvited and may disappear immediately. But sometimes it leaves behind a much more uncomfortable question: why did I think this?
That is where the real problem can begin. An involuntary idea becomes the object of analysis: "What if it means I am capable of doing it?", "Why would I think of something like that if I didn't want to?", "I need to make sure it will never happen." Paradoxically, the more we try to obtain a definitive answer or expel the thought, the more attention it may receive. Intrusive thoughts are also frequent outside of psychological disorders; what changes is how much meaning we attribute to them, how much distress they generate, and what we do to try to neutralize them.
What exactly is an intrusive thought?
An intrusive thought is an idea, image, impulse, or memory that appears involuntarily. It may have aggressive, sexual, or religious content, or be related to illness, accidents, contamination, mistakes, or any other matter the person considers important or disturbing.
One of its most disconcerting characteristics is that the content is often precisely contrary to what the person values. Someone deeply caring may imagine harming another person; someone very concerned about fidelity may experience repetitive doubts about their relationship; a religious person may have thoughts they consider offensive. The appearance of a thought does not in itself demonstrate a desire, an intention, or a personality trait.
Classic and later research on mental intrusions has found thoughts with content similar to some clinical obsessions also in people without obsessive-compulsive disorder (OCD). The difference between an everyday intrusion and a problematic obsession does not depend solely on how strange or unpleasant the idea is. Frequency, distress, the interpretation it receives, and the behaviors that appear afterwards also matter.
The problem may lie in what we do afterwards
Let us imagine that the thought arises: "What if I ran someone over without realizing it?" One person may consider it absurd and continue driving. Another may start mentally reviewing the last few minutes, repeatedly looking in the rearview mirror, driving back along the same road, and asking their companion if they are absolutely sure nothing happened.
The second person achieves something important: for a few minutes, they feel relief. Precisely for that reason, the pattern may repeat itself the next time. The brain learns that, when doubt appears, checking is necessary in order to feel safe.
Something similar happens with mental compulsions, which can be much less visible. Reviewing memories, endlessly analyzing what a thought means, replacing a "bad" image with a "good" one, mentally repeating certain words, or constantly seeking reassurance are all attempts to reduce uncertainty.
Cognitive models of OCD have particularly studied the importance of the appraisals we make about our own intrusions. Thinking "this is unpleasant" does not have the same consequences as concluding "if I thought it, it must mean something terrible about me." However, research also warns that no single psychological model explains every case.
Trying not to think about something can give it even more space
One of Daniel Wegner's classic experiments began with a seemingly simple instruction: try not to think about a white bear. Participants had to signal every time the animal appeared in their mind. Avoiding it proved difficult and, under certain conditions, trying to suppress it later increased its accessibility.
Wegner proposed that suppression contains a paradox. In order to verify that we are succeeding in "not thinking" about something, part of our cognitive system needs to monitor precisely whether that thought is appearing. In other words, to know whether we are not thinking about the white bear, we have to keep mentally searching for the white bear.
Later research has refined when this so-called rebound effect appears, so it cannot be claimed that any attempt to distract ourselves will inevitably make a thought increase. But the idea helps to understand a frequent experience: constantly struggling to expel an intrusion can turn it into something far more important than it initially was.
For this reason, addressing intrusive thoughts usually does not consist of learning a technique to ensure they never appear again. A more realistic goal is to change the way we respond when they do.
How to relate to intrusive thoughts in a different way
The first step may be to abandon the need to immediately determine what every thought means. Our mind produces an enormous amount of spontaneous content. Some ideas are useful; others are irrelevant, absurd, or unpleasant. Not all of them require an investigation.
It can be useful to identify the experience descriptively: "I am having the thought that this could happen," instead of automatically turning it into a statement about reality. The difference may seem small, but it helps to remember that a thought is a mental event, not necessarily a fact that we need to prove or refute.
It is also worth observing what we do to obtain reassurance. If every intrusion leads to checking, asking, searching for information on the internet, or analyzing for hours, those strategies may be maintaining the problem. Reducing them may initially produce more uncertainty, precisely because we stop obtaining the immediate relief we were used to.
This does not mean forcing ourselves to remain passive in the face of any reasonable concern. Checking once that we have locked the door is different from going back five times in search of a certainty that never seems sufficient. The key is to distinguish a functional behavior from a repetition aimed mainly at neutralizing anxiety.
When intrusive thoughts are part of OCD
Intrusive thoughts appear in many contexts and do not automatically imply obsessive-compulsive disorder. In OCD, however, obsessions are recurrent, generate significant distress, and are usually accompanied by compulsions or neutralization strategies that consume time or interfere with daily life.
A person may, for example, suffer from repeated thoughts about contamination and wash for hours; experience doubts about having made a mistake and check constantly; or have violent images that cause them so much anguish that they begin to avoid knives, children, or other situations for fear of losing control.
One of the psychological treatments with the strongest evidence for OCD is cognitive-behavioral therapy with exposure and response prevention (ERP). Exposure involves gradually approaching feared situations, thoughts, or doubts; response prevention consists of reducing the compulsions used to obtain reassurance. The NICE clinical guidelines recommend this approach even when compulsions are mainly mental and there are no easily observable rituals.
Its logic is not to prove over and over again that "nothing is going to happen." Rather, it allows one to learn to live with a reasonable degree of uncertainty without needing to constantly neutralize it.
You do not need to control everything that appears in your mind
One of the reasons why intrusive thoughts cause so much suffering is that we tend to confuse responsibility for our actions with absolute responsibility for our thoughts. We can choose many of our behaviors, but we cannot voluntarily select every idea, image, or association our mind generates.
Learning to relate to these intrusions involves stopping using them as evidence about who we are. It also means allowing some questions to remain without a perfect answer and redirecting attention back to what we were doing, even if the feeling of discomfort takes a while to subside.
The goal is not to achieve a mind in which a disturbing thought never appears, but a mind in which that thought does not automatically determine what we do afterwards. When intrusions take up a great deal of time, cause intense suffering, generate significant rituals or avoidance, or interfere with daily life, a psychological assessment can help determine whether they are part of OCD or another problem, and what treatment is appropriate.
In the specific case of thoughts about harming oneself or harming other people, their content alone does not reveal intention. If there is also a genuine desire to act, planning, or a feeling of loss of control, it is important to seek urgent professional help.
Source: Tomás Santa Cecilia. (October 6, 2026). Intrusive thoughts: what they are and how to learn to relate to them. Portal Psicología y Mente. https://psicologiaymente.com/psicologia/pensamientos-intrusivos-que-son-y-como-aprender-a-relacionarnos-con-ellos