Let us start by considering why some people catastrophise – that is, on hearing uncertain news, they imagine the worst possible outcome. After all, it is not uncommon and those who catastrophise seem to do it a lot. Catastrophisers tend to be fairly anxious people. Whether this characteristic is principally genetic or more the result of learning is unknown. High levels of anxiety are extremely unpleasant, so we look for ways to discharge those unpleasant feelings as quickly as possible. If a catastrophiser is told something inconclusive – for example, if they go to a GP and are asked to have tests – they look for a way to feel in control again immediately. They learn to choose the worst possible outcome because it allows for the greatest sense of relief when they are reassured.

Considering all possibilities is not a bad strategy if you examine them logically. However, unable to bear their distress, catastrophisers rush to external sources to calm themselves down: checking whether anyone else has “come through” the same problem; matching symptoms online to obtain a diagnosis and treatment options; asking a professional to tell them that they will survive. Once they are reassured, they feel better – in psychological jargon, they have “rewarded” this seeking behaviour. The next time they feel uncertain or threatened, they will ratchet up their anxiety with a catastrophic thought, then look outwards for reassurance even faster than before. In this way, catastrophising soon becomes a well-entrenched habit. The greatest problem with seeking others to alleviate anxiety is that it offers only temporary relief. There is always another source to check or another opinion to be had; as a result, catastrophisers feel anxious again increasingly quickly. The only way to break this cycle is to tame anxiety. After this, you can still seek advice. So, if you are a catastrophiser and you would rather not be, how do you go about making changes?

•Accept yourself. Anxiety is energy: if you are an anxious person, celebrate! However, why waste that energy feeling uncomfortable and preparing yourself for circumstances that will almost certainly never occur? Look for enjoyable ways to challenge yourself and use your energy more positively: taking regular aerobic exercise; learning something new; taking up a creative passion.

•Take control. Establish a regular “worry time”. Start by setting aside half an hour every day. Write down all your concerns in specific terms. For example: “I felt nauseated this morning. Do I have stomach cancer?” Assign a score on a scale of 0 to 100% to estimate how distressed this possibility makes you feel. Next, list all the possible explanations for your concern, then rank each one according to how likely it is to be correct. Make use of external sources if necessary, but stick with reputable websites and professionals. Finally, score your worry for the level of distress it is causing you now. Gradually, you will be able to reduce the amount and frequency of worry time.

•Use the “best friend test”. Ask yourself what you would advise your best friend to do about each concern, and take that action.

•Learn to self-soothe. Whenever you are overwhelmed by anxiety and feel you must seek reassurance, give yourself permission to do so – but not straight away. Establish an interval before you are allowed to act. Even two minutes is enough at first, because you are still exerting self-control. Breathing slowly in through your nose and out through your mouth, or taking some gentle exercise, will help. Gradually, you will find you can wait longer. When you get to the point where you can wait more than 20 minutes, most people find they no longer need to be reassured by others.

This three-pronged approach – using your “worry energy” to carry out new and enjoyable challenges, approaching your tendency to catastrophise logically and systematically, and learning to wait through discomfort – takes time. But if you invest the necessary time, you will start looking forward to each day knowing you can deal with uncertainty in a more positive, balanced way.