I will now share a powerful psychological tool in the Happy Thinking toolbox, the “Stop, Question, Ignore” (SQi) tool, which you can use to change unhelpful thoughts. Drawing on psychological concepts and conducting self-experiments, I developed this tool for my own use. I find it immensely useful and am very happy to share it with you.
The SQi tool consists of three simple words, which may seem nonsensical to you at first.

However, once I explain the simple concepts underlying these words, you will find them easy to use to change unhelpful thoughts.
In the following sections, I will explain, step by step, how to use the SQi tool.
Stop the thought
I will now explain the first word in the SQi tool, which is “Stop”.

In our minds, you can imagine that thoughts are constantly “moving”. This includes unhelpful thoughts.

When one notices an unhelpful thought in one’s mind, to deal with it effectively, one first needs to stop it from “moving,” making it stationary.
Holding the thought still helps one to engage with it. It’s a bit like when a child is running wildly around in a room; to talk to the child meaningfully, one will first need the child to stop running and become still. In the case of the child, one may shout her name loudly, for example, “Shelly!”, and this would, at least briefly, cause her to pause her running around. Once one gets her attention, one may be able to engage with her: “Shelly, it’s time for dinner!”

So, how can one make a thought that is speeding along in one’s mind come to a standstill? The answer is to use one’s inner voice. As soon as one senses an unhelpful thought occurring in one’s mind, one can use one’s internal voice to say as firmly as possible, “Stop!” What this does is to temporarily “freeze” the thought, so that one’s mind can engage with it.

It is essential to appreciate that using your inner voice to say “Stop” does not permanently eliminate unhelpful thoughts. If it did, life would have been great, as simply saying “Stop” a few times would clear our minds very quickly. Unfortunately, it is well known in psychology that merely saying “Stop” does not permanently stop thoughts. The SQi tool, therefore, uses the word ‘stop’ only to briefly pause the thought, just enough for one to engage with it. To help understand the SQi tool, let’s use an example. In the example, we will start with the “Stop” and then move on to the rest of the letters of the tool.
Imagine a person named Tom who has a routine blood test at his doctor’s clinic. At the time of the test, he is told that the results will be ready only in a week. However, during the week-long wait, Tom starts having unhelpful thoughts. Specifically, he begins to get the thought that he may have diabetes, although at this point, there is no real reason why this should be so. The thought of having diabetes starts to worry him unnecessarily.
Tom decides to use the SQi tool, and as soon as he senses the unhelpful thought about having diabetes, he says to himself, “Stop”. This inner voice command briefly holds the unhelpful thought in place while he moves onto the second step of the SQi tool.
Question the thought
Now that the unhelpful thought has been made stationary by saying “Stop”, we can proceed to the next step of the SQi tool, which involves questioning the unhelpful thought.

The purpose of questioning the thought is to help one’s mind understand and learn why the thought is unhelpful. The questions that one would ask the unhelpful thought will be very variable, depending on the type of unhelpful thought. However, for now, let us stick with our example of Tom imagining himself having diabetes while waiting for the blood test results.
A common theme of unhelpful thoughts is that they are often not based on actual evidence but on one’s imagination. In our example, when Tom was waiting for the results of his blood test, he relied on his imagination, concluding that the test would show diabetes rather than waiting for the definitive result. So, with unhelpful thoughts, a good question to ask is, “How much of this thought is my imagination and how much is reality?” Tom could ask himself, “What is the actual evidence I have that I have diabetes? Do I know the blood results before the laboratory releases them? etc”

Here are other examples of questions one might “ask” the unhelpful thoughts. Please note that these are only examples; I am sure you will be able to come up with questions that are more meaningful to specific unhelpfful thoughts you may have.
Unhelpful thought: Sally thinks, “Anne is a bad person because she forgot my birthday.”
Questioning the thought: Sally then questions her thought, “What about all the good things Anne has done for me over the years?”
Unhelpful thought: Mike thinks, “I got a promotion at work today, but also lost my expensive phone. Life is awful”.
Questioning the thought: Mike then questions the thought, “Was the day that bad? After all, yes, my phone was expensive, but on the positive side, I got a nice promotion at work.”
Unhelpful thought: Zara thinks, “I feel stressed, I need to eat a chocolate.”
Questioning the thought: Zara then questions this thought. “Is this a helpful way of dealing with stress? What are the unhealthy consequences of eating all this sugar?”
In the above examples, I limited each scenario to one question to keep the discussion brief. Of course, you could ask many more and vary them as you like. However, since the SQi tool is intended for daily use, it’s best not to make the questions overly complicated.
Let’s now move to the last step of the SQi tool.
Ignore the thought
We are now in the third and final step of the SQi tool, which is the word “Ignore”.

So far, we have briefly stopped the thought using the word “stop” and neutralised the thought using questions. Now, in this final step, which is “Ignore”, we want the thought to “go away”.
A fundamental concept in psychology is that pushing away or suppressing thoughts does not eliminate them. Just asking a thought to go away can even make it worse, as it will reappear with even greater strength. I can demonstrate this concept right now with a simple psychological experiment on you.
Here is the experiment for you:
“Please do not imagine a cat drinking milk.”
I bet you imagined a cat, even though I told you to do the exact opposite! This brief psychology experiment illustrates how, when you attempt to suppress a thought, it often resurfaces and becomes more prominent.
However, there is an alternative way to make a thought disappear. One just needs to “ignore” the thought. Ignoring means that, while you are aware that the thought is there, you do not engage with it. Eventually, the thought will fade away on its own. Ignoring is very different to suppressing a thought. By ignoring, you are not pushing the thought away. Instead, you are saying, I know the thought is there, but it does not influence me. A thought that you do not engage with will disappear. Imagine that you just ignored someone near you.

Eventually the person will get bored and will leave you.

Often, when using the SQi tool, the unhelpful thought fades away during the questioning itself. I.e. even before you think of ignoring it, the thought has left.
A helpful way to ignore a thought is to add another step, which I call “Move on”. Essentially, after one decides to ignore a thought, one moves one’s attention onto something else.
It is, of course, entirely possible for you to repeatedly face the same unhelpful thoughts over and over again. One will need to apply the SQi tool repeatedly to these repetitive thoughts, and with experience, you will become adept at catching the thoughts early. Eventually, one would hope that your mind learns about the unhelpful thoughts, and they will reappear less often. However, as these unhelpful thoughts may have been with you for years, it can take time for them to trouble you less.
As I described the SQi tool, it may have seemed “lengthy” to you. That is only because I broke it down into individual steps. While it may have taken you a while to read and understand the steps, in practice, the SQi tool takes only moments to do. And, like everything, with a bit of practice, it will become quicker. Eventually, you will find yourself using the SQi tools almost automatically.
Summary
In summary, when you suspect yourself of having an unhelpful thought, first say to yourself, “Stop”, so that you can freeze the thought. Then question the thought, to show your mind why the thought is unhelpful. Finally, ignore the thought, so that it fades away on its own accord.
Do try the SQi tool. It will take a few attempts for you to become familiar with it, but soon you will find it immensely useful in dealing with unhelpful thoughts.