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What are Intrusive Thoughts?
At their most basic, I would describe Intrusive Thoughts as being involuntary, unwanted thoughts that I am unable to control. That is to say that I have them whether I want to or not (which, to be clear, I’d rather not).
Before my mind starts to react to them, and apply a judgement, this is all that they are. They are just thoughts, albeit ones that I have not chosen to have. There meaning has yet to be determined (although this starts to take place straight away, so as to be practically instantaneous).
Now, that is not to say that these Intrusive Thoughts are random, or neutral, in nature. They are certainly not positive ones either. Fun is not a word I would use to describe them. Neither is fluffy, for that matter. These thoughts are negative thoughts, that tend to cause me to feel bad, anxious and uncertain in myself. They are therefore stressful and unpleasant to experience.
Nevertheless, it is still important to note that while the Intrusive Thoughts, and my subsequent negative reaction to them, are linked by a very well-trodden path, they are still two separate (albeit connected) things, whose relationship to one another can be changed. This is a topic I will focus on more in future articles.
So what do these Intrusive Thoughts mean?
It is crucial to understand that these Intrusive Thoughts are not a sign of some underlying desire, nor are they an indicator for some fundamental truth. That is to say that having these Intrusive Thoughts does not mean that there must be some truth to them. While there may well be a tru in Intrusive Thoughts, they are certainly not to be trusted. Instead, they are intruders.
So rather than being reliable signifiers, they should instead be seen as the result of a faulty mental alarm system. Everyone has a mental alarm system, with their brain flagging up things that it perceives as being important. In my case though, my system is faulty, which is causing it to go off far more often than it should be doing. In fact, it is so faulty that I simply cannot trust it.
Therefore the only conclusion that I can reliably draw from the fact that I am having these Intrusive Thoughts, is that I am indeed having them. Any other conclusion would be to put too much faith in the reliability of my brain to accurately tell whether or not a thought is important.
All of that is to say that the fact that I have these thoughts and am worrying about something, does not indicate that there is any truth to it. It just means that my brain has decided to worry about it, probably because of this faulty alarm system, perhaps combined with some trigger, or a low mood or something like that.
What is an example of an Intrusive Thought?
One of the difficulties I have when writing this blog, is my fear of inadvertently causing harm to someone reading it. Happily, at least for the purposes of this article, this means I can use an example of this meta fear that feels less ‘risky’ (*my therapist told me to use more neutral terms).
One fear then, is that by giving an example of a fear, I fear that this might trigger someone else to have that same thought, ultimately resulting in calamity for them. I said ‘calamity’ to avoid saying what I actually have in my mind, because another fear that appeared as I was writing, is that using the actual word in my mind, might cause the initial fear to come true, ‘calamity’ and all.
These thoughts can cause me to feel anxious and result in decision-paralysis. I have previously looked into trigger warnings and whether they can help. I have also spent time ruminating over whether the benefits of speaking more truthfully outweigh these risks (*chances?).
These worries also result in me changing my behaviour (in this case by changing what I am writing). My fear is both the risk itself, but also that taking that risk, however small or ‘normal’ it is, is morally unacceptable. Therefore my doing so would make me an awful person who no longer deserves a chance at life, even if the worst case scenario didn’t actually occur. At least this is what my mind is telling me, and is why I do not feel able to ‘risk’ it, even though I don’t actually think it is true.
What different sorts of Intrusive Thoughts do I have?
I will try to very roughly describe the different sorts of Intrusive Thoughts that I tend to have. These are very broad groupings. I am mainly using them to avoid having to devote an entire article to this at this time. So, here goes something I guess.
The first type are those that are based around past events. These usually relate to specific past events, including those that literally just happened. However they can also be about hypothetical events (usually set in an alternative past), and what I could have done, had things played out differently, or about a general fear that something might have happened, at some point that I may or may not remember. Whatever the case, my worries focus around my actions, my intentions, and in analysing the overall morality of my behaviour in those events.
The second type are based around moral dilemmas about my behaviour/decisions in the present or future (for instance the example about writing this blog). These occur in relation to decisions to do (or not do) something, and fixate on things such as the consequences of my actions/inaction, or the morality of certain choices and actions.
A third type are those that appear as nagging worries. They can be about a whole range of things. Examples include: contamination (of myself, not others, which belongs to the previous categories), the safety of those around me, health worries (which can also be a moral dilemma about how neglecting my health could impact those around me), and worries about the future (especially recently about AI). These worries are less self-confrontational (especially compared to the first type), but can be just as difficult.
Finally, there are thoughts that seem to serve no purpose other than being disturbing for me. These could include an impulse to behave inappropriately, disturbing mental-images (in so far as I can have mental images – perhaps concepts of images is a more accurate description), and random urges (such as to put my fingernails between my front teeth). I am less likely to believe these ones mean anything. I have however blamed myself at times for not doing enough to prevent them, especially the mental-image ones. This is despite the fact that I cannot actually control them, and wouldn’t choose to have them. And I certainly don’t enjoy having them either.
What can trigger them?
Intrusive Thoughts can be triggered by a whole range of things, including something I have seen, read, or thought about. They can also just appear seemingly out of nowhere, thanks to my lovely brain, with no real link. This is especially common for me when I have just woken up.
They can also be caused by things that I do, for instance when I come across a moral dilemma, or if I do something that I then fear was wrong, and that I cannot undo, and fear that I have made a huge mistake that I can never move past.
They can also be triggered by anything that appears to be ‘new evidence’. This could be something that makes me question how a past event unfolded, look upon an existing worry/event from a new angle, or re-evaluate the morality of certain behaviour. These thoughts can be particularly hard to ignore, as they can bypass past reassurances, even with minimal changes, sort of like a virus mutating slightly to bypass your immune system.
However, I wouldn’t want to give the impression that my OCD is reasonable and evidence-based, and only triggers these thoughts when there is a good reason to. It really isn’t reasonable, no matter how much it tries to present itself as such.
As such, I can for instance have been over a thought plenty of times before, and yet my brain still demands to go over it yet again, for no real reason. So why is this, when there is no clear action or trigger for it?
What else can cause Intrusive Thoughts?
Just as importantly as all of the trigger above, are the things that don’t seem to be the cause, but in fact are. These can include: being hungry, cold, tired, or low, having just woken up, having done too much and exhausted myself, or having done too little and become bored and let my mind wander, or indeed pretty much anything else.
When I am feeling low, or vulnerable in some way, then my mind will find some worry to fixate on. When I am in a better position, then this doesn’t happen as much. This is usually a more influential factor than what appears to be the trigger for them. This is why for instance at points when I am feeling low, I feel like I can average more than one ‘life-ruining mistake’ a day, which eventually turned out to be nothing. Because had I been feeling better, I probably wouldn’t even have given whatever it was a second thought, let alone spending a day or more engulfed by it.
When I was at my worst I would pretty much always have some thoughts lining up. As soon as I had ‘dealt with’ one thought, another would come along. This would be for no other reason than that I wasn’t currently worrying about something. If there needed to be any reason at all that is. Perhaps it has just been a while since I last reassured a certain thought.
Some while some Intrusive Thoughts do have some independent strength, it is far more usually the case that my emotional state is causing the thoughts, rather than the other way around.
What impacts how I feel about them?
The severity of the experience can depend on: the extremity of the thought itself (ie. the consequences/implications of it being true), how true it feels, and my general mood/frame of mind. There is also the factor of how disturbing the Intrusive Thought itself is, although this is a somewhat separate dimension to the experience.
I would also like to say that I have got far better at coping with my Intrusive Thoughts. The emotions they cause are still unpleasant, but this lasts for a far shorter amount of time. I can also almost always avoid spiralling now. I can sometimes go for whole days without any real negative experiences beyond a few seconds of milder feelings.
How do I feel after having them?
These are only certain points on what is a whole spectrum of possible experiences.
At their mildest, the Intrusive Thoughts are merely a bit unpleasant, as well as perhaps a bit frustrating. They have a brief unpleasant impact, during which I feel perhaps a little better unsettled, after which I can go about my day as normal. Sometimes, they cause no problems at all.
At their worst, which is usually caused by past-event thoughts, they are completely terrifying. It can feel like everything my mind is telling me is true. My heart feels like it is sinking. I feel like I am dissolving and everything is collapsing around me. I believe my brain when it tells me that I did something awful/am an awful person. My brain is telling me that my life is over, which feels so real and overwhelming. I feel the urge to go through the thought over and over again, until I have satisfied myself that these thoughts are either not true, or at least are not as bad as they seem.
Then of course, there are all the things in between these two extremes. This includes feeling hopeless, worried, or just generally sad about everything and nothing. There are also the thoughts that are disturbing in and of themselves. These thoughts are cruel and bullying, but at least with these I am on my own side. I am able to feel sympathy towards myself, which helps a lot.
These are my initial, short-term reactions, caused by the Intrusive Thoughts themselves, and my instinctive, instant reaction to them. There is also the next stage, of how I respond to it (and how well the response goes in the moment). This is something I will get to in the next article (Intrusive Thoughts, Part 2).
Last Updated: 3rd September 2026
