Intrusive thoughts: Why do we get them?

Did you know that the average person has around 12-60 thousand thoughts per day? A study by the National Science Foundation found that 80% of those can be negative thoughts.
Let that sink in for a moment.


If we are having that many thoughts per day, and a big chunk of them are not positive, is it any surprise that some of us struggle with intrusive thoughts that can affect our day to day lives? Probably not. Unfortunately, the brain actively wires itself towards negative thinking; this goes back to the human response of fight or flight and the need for survival. As environments and people change, the brain often gets left behind. Understanding how and why our brain processes thoughts is fundamental in any mental health condition, and intrusive thoughts are no different.

Intrusive thoughts take any form, but they are usually formed around concerns for yourself or someone you care about

The truth is every single person on the planet experiences intrusive thoughts.

The content of these thoughts, although they may seem alien, scary, or confusing, can pass after a few moments. Sometimes though, these thoughts can alarm us so much that they stick around for longer, which can result in conditions such as Obsessive-Compulsive Disorder, but that is not to say if you have intrusive thoughts that, you have OCD.

These thoughts that can stick with us, often disturbing thoughts that cause us deep anxiety and distress. It’s our anxious response to them that fuels the intrusive thought cycle and therefore, we are not capable of brushing them aside and labelling them as meaningless. We feel like we have to find out more about the origin of the thought and what it means about us as a person.

Why do we get intrusive thoughts?

Our brains have a negativity bias and favour negative thinking, and with that, some intrusive thoughts are inevitable. But why do they stick with some people when others can let them flow in and out? There is no clear answer to this, but a good analysis would be that it’s down to the response to the initial thought, which can form the path in how the thoughts grow or dissolve. How some can let them come and go and how others latch onto them.

For example, an individual with a naturally overactive brain, or anxious tendencies could react to an intrusive thought from a feeling of fear.  This reaction often occurs if the theme of the thought targets something very important in that person’s life. This reaction then makes the individual think that because they have had the thought, that they may act on it. This, in turn, makes the thought more threatening and can spiral into a confusing and scary place, showing the brain that there is something to worry about. But so often, there is not; it’s merely our immediate reaction to the thought (increased heart rate, questioning the validity, digging for answers) and not a reflection of our life or values that fuels the anxious cycle.

Examples of unwanted, distressing intrusive thoughts:

  • Pushing someone in front of a train or jumping in front of a train yourself
  • Hurting a child
  • Questioning your relationship
  • Shouting out unpleasant comments in public
  • Questioning your sexuality
  • Thoughts about suicide
  • Crashing into a wall when driving


Intrusive thoughts categorize into five different categories:

  1. Violent thoughts: hurting oneself or others or causing harm.
  2. Sexual thoughts: engaging in unwanted or inappropriate sexual activities 
  3. Blasphemous thoughts: going against religious or moral beliefs.
  4. Harm-related thoughts: getting sick or being in a dangerous situation.
  5. Self-doubt thoughts: thoughts that you are not good enough or have made a mistake.


The examples above are all disturbing to people in one way or another, and what they all have in common is that these thoughts go against what the person knows themselves to be. Either in terms of their behaviour or their beliefs and values about themselves and their lives.

People bothered by intrusive thoughts need to form a new relationship with them—that their content is irrelevant and unimportant.

That’s where CBT comes in. How Cognitive behavioural therapy works is that it looks at the connection between how you think, how you feel and how you behave. How you approach these unhelpful thoughts and self-talk can help you work out different ways of thinking and behaving so you can cope better, whatever life may bring.

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Are intrusive thoughts common?

Intrusive thoughts do not necessarily mean a person has a mental health disorder or condition. Research suggests that intrusive thoughts are a natural part of the human experience and that nearly everyone experiences them at some point. However, suppose intrusive thoughts are causing significant distress, anxiety or interfere with a person’s daily functioning. In that case, speaking with a mental health professional for support and guidance may be helpful. 

It is important to note that the term “normal” is not commonly used in mental health as it can be subjective and vary depending on cultural, social, and personal factors. What is considered normal for one person may not be for another.

Why do we have intrusive thoughts?

Intrusive thoughts can occur due to various factors, including anxiety, stress, depression, trauma, or other underlying mental health conditions. They may be due to imbalances in brain chemistry, environmental stressors, or learned thought patterns. 

What is the difference between impulsive thoughts and intrusive thoughts?

While intrusive thoughts are unwelcome and often distressing, impulsive thoughts refer to sudden urges or thoughts that drive impulsive actions without much consideration of consequences. These thoughts often arise from strong emotions, desires, or impulses and can lead to impulsive actions without adequate reflection or planning.

Examples of impulsive thoughts could include sudden urges to buy something impulsively, engage in risky behaviour, or react impulsively to emotional triggers. Impulsive thoughts can be a feature of various conditions, including attention deficit hyperactivity disorder (ADHD), borderline personality disorder (BPD), or substance abuse disorders.

Why causes intrusive thoughts?

Intrusive thoughts are more common in individuals with anxiety disorders, obsessive-compulsive disorder (OCD), post-traumatic stress disorder (PTSD), and other mental health conditions. Intrusive thoughts can cause significant distress and interfere with daily life if left untreated.

Obsessive Compulsive Disorder (OCD)

One of the most common symptoms associated with OCD and other anxiety disorders is intrusive thoughts – these are recurring, unwanted, and distressing thoughts or images that can cause significant distress and interfere with daily functioning. Intrusive thoughts can manifest in different ways, such as repetitive worries about contamination or harm, intrusive sexual or violent thoughts, or excessive concerns about one’s morality or values.

Living with OCD and managing intrusive thoughts can feel like being stuck in a never-ending loop of negativity and compulsions. It is easy to feel like these thoughts are a reflection of an individual, but they’re not. 

While it is common for people to ruminate from time to time, in OCD, this rumination is impacting significantly on daily life. In the UK, OCD is thought to be much more common than people realise, with estimates of those with the condition suggesting between 1–2% of the population have OCD. That’s anywhere between 600,000 and just over one million people. 

People living with undiagnosed OCD often don’t realise the impact of the intrusive thoughts, and so these cases can get missed, misunderstood or misdiagnosed as another mental health condition. 

Post-Traumatic Stress Disorder (PTSD)

In the context of PTSD, intrusive thoughts often relate to the traumatic event that the individual experienced. These thoughts can be vivid and intense and cause significant distress as they replay the traumatic experience or aspects of it. The thoughts may involve reliving the event itself, specific details, or associated emotions. They can be distressing and overwhelming, leading to feelings of fear, anxiety, or a sense of being trapped in the memory.

Intrusive thoughts experienced in PTSD can trigger various reminders of the traumatic event, such as certain sounds, smells, or situations that resemble the original trauma. These triggers can activate a cascade of intrusive thoughts, making it challenging for individuals with PTSD to control or suppress them.

How to stop intrusive thoughts?

Cognitive Behavioural Therapy (CBT) is a widely used and practical approach for managing and identifying negative patterns of thinking and developing new, more positive ones. A BABCP-accredited CBT therapist can work with individuals to identify the root causes of their intrusive thoughts and develop practical strategies to manage them.

The aim of CBT Therapy in treating intrusive thoughts is not completely to get rid of these thoughts. A person cannot avoid how they think, but instead, CBT helps a person with OCD to identify, challenge and manage the patterns of thought and compulsive behaviours that cause their anxiety and distress.

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Cognitive Behavioural Therapy manages intrusive thoughts by:

Cognitive Restructuring
Exposure and Response Prevention (ERP)
Mindfulness and Acceptance-Based Strategies
Relaxation and stress-reducing techniques
Assessing thoughts without judgement
Understanding the fear associated with thoughts

How can CBT help individuals manage unwanted thoughts?

Cognitive restructuring

CBT aims to help individuals identify and challenge negative thinking patterns that contribute to anxiety and distress. Individuals may have unhelpful beliefs or assumptions about the meaning or significance of their thoughts. For example, they may believe that having an intrusive thought about harming someone means that they are a bad person or that they are at risk of acting on the thought.

Working alongside a nationally accredited therapist using techniques and tools learned in CBT can help individuals challenge these beliefs and improve their ability to manage them. Examine the evidence for and against thoughts and beliefs, testing them out via a behavioural experiment, and developing more balanced interpretations of intrusive thoughts. 

Exposure and Response Prevention (ERP)

Exposure and Response Prevention (ERP) is a technique used in CBT therapy to help individuals reduce their anxiety and distress related to intrusive thoughts. ERP involves gradually exposing individuals to the situations or stimuli that trigger their anxiety while preventing the individual from ‘putting them right’ or ‘balancing’ them with compulsions or avoidance behaviours.

Over time, continued exposure helps reduce the anxiety and distress associated with particularly negative thought patterns and reduce the need for compulsive behaviours.

Mindfulness and Acceptance-Based Strategies

Mindfulness and acceptance-based strategies are increasingly being integrated into CBT for mental health conditions that can cause intrusive thoughts. These approaches aim to help individuals develop a self-compassionate and accepting attitude towards their thoughts and feelings. Individuals learn to observe and accept their thoughts without trying to control or suppress them. 

Relaxation and stress-reducing techniques

In addition to the cognitive and behavioural strategies discussed above, CBT can also incorporate relaxation and stress-reduction techniques to help individuals. These techniques can include deep breathing, progressive muscle relaxation, guided imagery, and mindfulness meditation. These techniques can also be helpful for improving sleep quality, reducing muscle tension, and promoting overall well-being.

Quick tips for managing unwanted intrusive thoughts:

  • Label these thoughts as “intrusive.”
  • Accept and allow the thoughts into your mind.
  • Educate yourself on the brain and how it works.
  • Do not try to push the thoughts away – but gently move your attention onto something else.
  • Practice allowing time to pass.
  • Do not engage and search for the meaning of them.
  • Expect the thoughts to come back again.
  • Continue whatever you were doing prior to the thought while allowing the anxiety to be present
CBT Therapy For Managing Intrusive Thoughts

Diagnosis and treatment

Unwanted thoughts are distressing and confusing, but with the help of a skilled CBT London therapist for online and UK-wide face-to-face therapy, it is possible to treat and regain a quality of life. Onebright therapists and psychiatrists are fully licenced and have been helping people in the UK and abroad get an accurate diagnosis and treatment plan together, reducing the impact that mental health challenges have on daily life.

Don’t let intrusive thoughts take hold of you and your loved ones any longer. Book an appointment and one of the Onebright team will contact you shortly. 

Book an Appointment
We offer online, phone or face to face therapy. Contact us to get matched to the right therapist for you.
Book appointment
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