Sometimes, in circumstances completely out of anyone’s control, a niggling thought breaks the tranquility of an otherwise unremarkable day. The said thought can feature violence, sex, or a general darkness, which, if fixated upon, can lead to complications with someone’s mental health. Intrusive thoughts, as they’re commonly known, are by their nature unwelcome: they can leave people feeling bewildered and confused as to why they have such uncharacteristic thoughts in their own minds.

Researchers have extensively documented this phenomenon, and have found it to be more prevalent in individuals living with Obsessive Compulsive Disorder (OCD), Post-traumatic Stress Disorder (PTSD), and anxiety. Even in the general population without these conditions, however, intrusive thoughts often make their way into people’s heads unbidden. Although these thoughts are often disturbing for the people who have them, trying to suppress them can make them worse — even spiraling the thought process further into a heightened risk of mental illness.

Dealing with intrusive thoughts can feel like a battle against one’s own mind because of how they appear against our better nature. The content of the thoughts themselves make them difficult to talk about, and are thus often laden with stigma. Studies have also shown that the more distressing the thought, the more likely people are to resort to unhelpful strategies to try and combat them. The irrational imagery of hurting someone, for instance, or oneself; any kind of inappropriate sexual imagery, or even something blasphemous for the religious minded is all thoughts that we don’t endorse and would never act upon — which is what makes them so upsetting.

For people living with OCD, these thoughts often fall into a few well-defined categories: “contamination, symmetry and doubting, and harming, religious, or sexual obsessions,” as per one study. The stigma around some of these thoughts — especially those that have to do with sexual obsessions — makes people disclose them, which can in turn delay treatment. Moreover, disclosing thoughts with sexual themes is associated with more social rejection — further adding to the fear and distress while experiencing them.

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But intrusive thoughts could also be rooted in real-life anxieties — doubts about unfinished tasks, being afraid of saying or doing the wrong thing in public, or germaphobia. “Some unwanted intrusive thoughts consist of repetitive doubts about relationships, decisions small and large, sexual orientation or identity, intrusions of thoughts about safety, religion, death or worries about questions that cannot be answered with certainty,” psychologists Martin Seif and Sally Winston note. Nearly everyone has experienced intrusive thoughts, and thoughts about incomplete tasks were reported to be the most common types of intrusive thoughts, Healthline noted.

While it isn’t clear where intrusive thoughts come from or why they even do, some studies have suggested that sleep deprivation could be one factor. Age could be another: some research has shown that older adults are better at managing the emotional effects of intrusive thoughts than younger adults. Further, some experts note that the pandemic and the isolation that came with it may have exacerbated the phenomenon among many.

Particular facets of mindfulness, in addition to cognitive behavioral therapy (CBT), can help people with intrusive thoughts. Among these measures is also the idea of non-judgment, where people don’t interpret the thought as being reflective of who they are as people. Unintentionally thinking about something violent, aggressive, or disturbing doesn’t necessarily have to be a character-defining trait.

New research, published in the journal Computational Biology recently, adds to our understanding of intrusive and unwanted thoughts by showing how we can prevent them from arriving in the first place. It is indeed possible to control intrusive thoughts, or at least reduce their frequency.

It has to do with two cognitive processes: reactive control and proactive control. The former is what keeps unwanted thoughts in our minds by reacting to them — essentially, engaging them to unwittingly create a loop. “As our findings suggest, thoughts are self-reinforcing: thinking a thought increases its memory strength and the probability that it will recur,” researchers of the present study note.

Here is where proactive control comes in — it’s when someone acts to prevent unwanted thoughts from even occurring. This can happen if common word associations are replaced — for instance, replacing “chair” in the word association “table-chair” can, over time, lead to the new association taking over. But while the study showed how pre-empting unwanted thoughts and preventing them from occurring is possible, it doesn’t show how this can be achieved.

One of the most important things about intrusive thoughts, however, is that much like many other types of thoughts (like earworms, for instance), they aren’t within our control — and therefore, don’t have anything to say about who we are as people. In trying to cope with them, most people make the common mistake of ascribing meaning to these thoughts. But as Seif and Winston note: “[P]eople with violent unwanted intrusive thoughts are gentle people. People who have unwanted intrusive thoughts about suicide love life. And those who have thoughts of yelling blasphemies in church value their religious life.”