BioBeyond

Beyond Intrusive Thoughts

• Jean

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Nearly everyone experiences intrusive thoughts, which are disturbing thoughts that seemingly materialize out of nowhere. Any sort of disturbing thought that causes distress can be classified as intrusive thoughts, which can cause worry or anxiety. In today’s BioBeyond, we’re going to explore both the social side and scientific side of intrusive thoughts.

Sources List

  1. Abraham, M. (2020, October 10). Anxiety and intrusive thoughts: An introduction. Calm Clinic - Information about Anxiety, Stress and Panic. Retrieved May 26, 2022, from https://www.calmclinic.com/anxiety/signs/intrusive-thoughts
  2. Bilodeau, K. (2021, October 1). Managing intrusive thoughts. Harvard Health. Retrieved May 26, 2022, from https://www.health.harvard.edu/mind-and-mood/managing-intrusive-thoughts
  3. Scientists identify mechanism that helps us inhibit unwanted thoughts. University of Cambridge. (2017, November 3). Retrieved May 26, 2022, from https://www.cam.ac.uk/research/news/scientists-identify-mechanism-that-helps-us-inhibit-unwanted-thoughts
  4. Kühn, S., Schmiedek, F., Brose, A., Schott, B. H., Lindenberger, U., & Lövden, M. (2013). The neural representation of intrusive thoughts. Social cognitive and affective neuroscience, 8(6), 688–693. https://doi.org/10.1093/scan/nss047 
  5. Rebetez, M., Rochat, L., Barsics, C., & Van der Linden, M. (2018). Procrastination as a Self-Regulation Failure: The Role of Impulsivity and Intrusive Thoughts. Psychological reports, 121(1), 26–41. https://doi.org/10.1177/0033294117720695 
  6. Koenig-Robert, R., & Pearson, J. (2020). Decoding Nonconscious Thought Representations during Successful Thought Suppression. Journal of cognitive neuroscience, 32(12), 2272–2284. https://doi.org/10.1162/jocn_a_01617 
  7. Schmitz, T. W., Correia, M. M., Ferreira, C. S., Prescot, A. P., & Anderson, M. C. (2017). Hippocampal GABA enables inhibitory control over unwanted thoughts. Nature communications, 8(1), 1311. https://doi.org/10.1038/s41467-017-00956-z 
  8. Sreenivas, S. (2021, March 22). Intrusive thoughts: What are they? WebMD. Retrieved May 26, 2022, from https://www.webmd.com/mental-health/intrusive-thoughts

Episode 2: Intrusive Thoughts

Nearly everyone experiences intrusive thoughts, which are disturbing thoughts that seemingly materialize out of nowhere. Any sort of disturbing thought that causes distress can be classified as intrusive thoughts, which can cause worry or anxiety. In today’s BioBeyond, we’re going to explore both the social side and scientific side of intrusive thoughts.


0:24 Intrusive thoughts can be unwanted memories, such as in people with PTSD, or unwanted violent or sexual thoughts (1). Other types of intrusive thoughts include negativity, paranoia, and other types of thoughts that are just strange in general (8). While these thoughts can induce shame and worry, it’s important to realize that they’re incredibly common. Intrusive thoughts affect about six million Americans (2), so if you’re struggling with them, you’re absolutely not alone. They can be triggered by stress, anxiety, or even hormone shifts. Stress and isolation can also increase the likelihood of having intrusive thoughts (2).

1:02 Many people who experience intrusive thoughts don’t have any associated mental health disorder. However, some disorders can affect the likelihood or severity of having intrusive thoughts. For example, Obsessive-Compulsive Disorder (OCD) causes individuals who have it to obsess over certain thoughts. This is where certain compulsions come in, as people with the disorder try to remove their distressing thoughts by turning to compulsions, like doing routine activities repeatedly. Similarly, fear of germs, often associated with OCD, can be classified as an intrusive thought that affects behavior. Anxiety can also affect intrusive thoughts, although they are usually less intense than thoughts associated with OCD. The worries associated with Generalized Anxiety Disorder   (GAD) can manifest as intrusive thoughts, such as being worried about a family member and needing to check in with them to stop the worries. PTSD can also cause intrusive thoughts, like flashbacks to the traumatic event that caused the disorder. 

1:59 Some intrusive thoughts can resolve on their own, and may not even warrant seeking help. The easiest way to deal with intrusive thoughts is to identify them, and not try to suppress them. Thinking about intrusive thoughts too much leads to heightened stress and anxiety. Instead, the best thing to do is to accept that you are experiencing intrusive thoughts, and don’t try to suppress it. 

2:29 However, when intrusive thoughts get bad enough to disrupt people’s daily lives, there are some treatment options available. Cognitive behavioral therapy is one option to help people manage their thoughts and lessen their frequency. With some causes of intrusive thoughts, like anxiety disorders or trauma, treatment may need to address the underlying cause to lessen the intensity of the thoughts (2). 

2:45 Intrusive thoughts are a common thing that many people experience in their everyday lives. However, what people might not know is what areas of the brain are behind their occurrence. In a study by Ghent University, participants were asked to perform computerized tasks such as word recall and location memory while using fMRI imaging to view the brain. This stands for “Functional magnetic resonance imaging”, and detects changes associated with blood flow in the brain in order to map brain activity in a non-invasive way. Intrusive thoughts were measured by asking the participants whether they were struggling with getting certain thoughts out of their mind, and thinking about something over and over. Emphasis was placed on thoughts about oneself. Individuals who self-reported higher levels of intrusive thoughts were shown to have greater brain activity in the left IFG (Broca’s area) and in the cingulate cortex (CC), showing similar magnitude of correlation between younger participants and older participants. The left IFG is an area of the brain that is part of the prefrontal cortex in the frontal lobe. This area is important for both language processing and inhibitory control. Meanwhile, the cingulate cortex is part of the limbic system, which is important for emotion formation, learning, and memory. Activation in the left IFG was the most consistent, showing activity across multiple task types. Left IFG activation has been associated with language in previous studies, so it is possible that intrusive thoughts are connected to the processing of language in the brain. Because of this association with language, it is possible that people who regularly experience intrusive thoughts may have stronger and more habitual internal speech processes. (4) 

4:31 Intrusive thoughts are also associated with procrastination, as procrastination is also viewed as a failure of self-regulation. In a study by the University of Geneva, it was shown that high procrastination was associated with a high frequency of intrusive thoughts. Impulsivity is designated with the four components: urgency (strong reactions), premeditation (planning), perseverance (ability to focus), and sensation seeking (desire for new or exciting activities). Of these, urgency and lack of perseverance are correlated with intrusive thoughts. Urgency is related to thoughts similar to obsessions and worries, while lack of perseverance is associated with thoughts such as daydreams and distractions. In the study, participants were assessed with various behavior scales and questionnaires, and the data showed that people who are more ruminatory (in deep thought) have higher urgency, which is associated with both procrastination and intrusive thoughts. (5)

5:31 Unwanted thoughts persist in parts of the brain even when they are attempted to be suppressed. The University of New South Wales conducted a study that used neuroimaging to approach the concept of suppressing unwanted thoughts. In this study, participants were asked to suppress thoughts or images of a red apple or a green broccoli for twelve seconds. They were asked not to replace it with other images, but to keep their mind clear. Out of the twelve participants, eight stated that they had succeeded in the task, but MRI data showed that there was still a representation of the thought in their minds. The parts of the brain that the thoughts persisted in were the visual cortex, as well as the lateral occipital cortex, which recognizes objects. This data may explain why people have so much difficulty suppressing intrusive thoughts, as the thoughts still remain inside their brains even when trying to suppress them (6). 

6:23 The chemical that may be responsible for inability to suppress unwanted thoughts was investigated in a study by the University of Cambridge. The hippocampus is a region of the brain that is associated with memory, and hippocampal hyperactivity is thought to be associated with difficulty controlling intrusive thoughts. The inhibition of the inhibitory anti-anxiety neurotransmitter hippocampal GABA creates a pathway that controls intrusive thoughts. fMRI imaging was used to assess participants’ brain activity while using the think/no-think paradigm, which is a task developed to study suppression of memories or thoughts. Within the think/no think paradigm, people are asked to associate word pairs together, then are prompted to either recall the word or stop thinking about the word. fMRI imaging allows researchers to investigate what participants are thinking of. The GABA concentration in the hippocampus was quantified with the imaging technique H magnetic resonance spectroscopy (H MRS). People with less hippocampal GABA were less able to suppress hippocampal activity, leading to worse instances of intrusive thoughts (7, 3). 

7:34 These findings shed light on the mechanisms of intrusive thoughts, important because they are a symptom of so many psychological disorders. One disorder that benefits from these discoveries is schizophrenia. Many people with schizophrenia have suboptimal inhibitory neurons, and the discovery of hippocampal GABA’s role in intrusive thoughts may help with treatments—improving GABA activity could help suppress the hippocampus and stop intrusive thoughts. 

8:11 While intrusive and unwanted thoughts are associated with many different disorders, it is important to remember that at the end of the day, they are common and nothing to worry about. They do not reflect one’s actual desires, and the best way to manage them is to accept they are there and that they do not reflect reality. 

Sources List

  1. Abraham, M. (2020, October 10). Anxiety and intrusive thoughts: An introduction. Calm Clinic - Information about Anxiety, Stress and Panic. Retrieved May 26, 2022, from https://www.calmclinic.com/anxiety/signs/intrusive-thoughts
  2. Bilodeau, K. (2021, October 1). Managing intrusive thoughts. Harvard Health. Retrieved May 26, 2022, from https://www.health.harvard.edu/mind-and-mood/managing-intrusive-thoughts
  3. Scientists identify mechanism that helps us inhibit unwanted thoughts. University of Cambridge. (2017, November 3). Retrieved May 26, 2022, from https://www.cam.ac.uk/research/news/scientists-identify-mechanism-that-helps-us-inhibit-unwanted-thoughts
  4. Kühn, S., Schmiedek, F., Brose, A., Schott, B. H., Lindenberger, U., & Lövden, M. (2013). The neural representation of intrusive thoughts. Social cognitive and affective neuroscience, 8(6), 688–693. https://doi.org/10.1093/scan/nss047 
  5. Rebetez, M., Rochat, L., Barsics, C., & Van der Linden, M. (2018). Procrastination as a Self-Regulation Failure: The Role of Impulsivity and Intrusive Thoughts. Psychological reports, 121(1), 26–41. https://doi.org/10.1177/0033294117720695 
  6. Koenig-Robert, R., & Pearson, J. (2020). Decoding Nonconscious Thought Representations during Successful Thought Suppression. Journal of cognitive neuroscience, 32(12), 2272–2284. https://doi.org/10.1162/jocn_a_01617 
  7. Schmitz, T. W., Correia, M. M., Ferreira, C. S., Prescot, A. P., & Anderson, M. C. (2017). Hippocampal GABA enables inhibitory control over unwanted thoughts. Nature communications, 8(1), 1311. https://doi.org/10.1038/s41467-017-00956-z 
  8. Sreenivas, S. (2021, March 22). Intrusive thoughts: What are they? WebMD. Retrieved May 26, 2022, from https://www.webmd.com/mental-health/intrusive-thoughts