<h1>Introduction</h1>Cognitive bias has existed in all disciplines, including Medicine, for centuries. In this short article, I cover how you shouldn’t believe everything you think and ways to reduce clinical diagnostic errors: so you can be the genius FY1 on the wards!&nbsp;Cognitive bias is defined as the thought process caused by the tendency of the human brain to simplify information processing through a filter of personal experience and preferences. Thus, it leads to doctors seeing only what they want to see. This occurs when a clinician refuses to consider alternative differentials once an initial diagnosis has been established, despite contradicting data, such as investigation results. It underpins human brain evolution, explaining that we are more likely to base our clinical reasoning on cognitive shortcuts and familiarity.Illustrated this as an example, let’s say we have a 65 years old gentleman who presents to ED with epigastric pain and says it is the ‘gastric ulcer’ that he had in the past.PMH: ulcerative colitis and peptic ulcer diseaseFH: nilPatient insists the GP provided safety net advice to seek medical attention, should the symptoms return in the future.At first, most of us will think there is a plausible link between epigastric pain and gastric ulcers. Thus, we are much more likely to only do examinations and tests to prove the easy hypothesis: the gastric ulcer is causing the pain. The human brain has evolved over time to preserve cognitive energy, thus our reasoning jumps on the easiest patient’s perception of the situation, rather than applying a holistic approach to the clinical management.If we are not actively interrogating and reflecting on our cognitive bias, we can end up being one of those clinicians who will end up missing the acute pancreatitis presentation of the patient above; this is due to our cognitive bias that challenges our clinical reasoning and prevents from taking a comprehensive history. Had you done so, you would have extracted the patient is on a high dose steroid treatment for a recent ulcerative colitis flare up.I hope you can appreciate how easy it can be for any of us to make similar mistakes. Let’s work through common cognitive biases encountered in clinical practice and strategies that you can apply to minimise those.<h1>Types of cognitive bias</h1><blockquote><h2>Anchoring</h2></blockquote>All stages of medical training we have experienced anchoring cognitive bias. It describes the tendency of the clinician to only consider the investigation results that support their initial diagnostic impression, even when the diagnosis might be wrong.For example, a 21 years old male patient, on a background of Hodgkinson’s lymphoma treated with chemotherapy, presents with dyspnoea and insists that the oncologist explained that the breathlessness is likely to results from anaemia and he’ll require a blood transfusion. As a FY1, you are likely to respect a senior oncology consultants advice and at most do a few bloods to back that impression up. The blood results are as follows:FBCHb 8.6 g/dl (normal range 13.2 to 16.6 g/dl)Platelets 660 109/L (normal range 150 to 400 109/L)As an FY1, you are likely to confirm the patient’s hypothesis that it is an anaemia as evidently shown by the low haemoglobin and perhaps put the raised platelets down to some unknown inflammation.This is anchoring bias as you are only considering the blood results that satisfies your initial impression, as right for the brain it is a lot of hard work to think of defferentials when the answer has been given to you by the patient.However, if you are a good FY1, you will compare this results with previous ones and identify that the haemoglobin has been 8.6 g/dl for the last 6 months and the patient has been asymptomatic until now. This makes anaemia a less plausible answer, and take your attention to the raised platelets. With a quick search on Google, you’ll soon realise that ‘dypnoea with raised platelets’ is a sign of pulomary embolism. Ta da! You do a CT PA which confirms the ventilation perfusion mismatch and your patient can now been currently treated.I hope you can appreciate how easy it is to fall down the trap of believing what you want to, rather than considering all evidence holistically.&nbsp;<h2>Diagnostic momentum</h2>Diagnostic momentum is another practiced cognitive bias in healthcare setting. It is defined as the tendency of a diagnosis to be passed on amongst healthcare professionals, with scarce underlying evidence for its validity.Essentially, on the wards this is exemplified by the junior blindly believing the registrars or consultants diagnosis and doing the sheep work for it (essentially feeding the anchoring bias of the team you are part of). By no means, I am implying to question every diagnosis your consultant makes, but rather whenever you are asked to order an investigation or blood test, clarify with them the indication of it. This will also help you to write a background for the patient, where ordering a scan for example which gives you a higher probability of your request to be accepted.<h1>Summary</h1>It is essential to autopsy your cognitive bias every now and then, to ensure you are not unconsciously influencing your decision making. As medical students and doctors, we are incredibly knowledgeable but controlling your cognitive bias is what makes the best doctors!Making mistakes is important to learn, but in this article my focus has been on altering our ways of thinking and controlling our biases, so that we are not making errors on things we can actually regulate!No one is perfect, but understanding cognitive bias provides a different approach to continuously improve ourselves and become the BEST VERSION OF OURSELVES.Lots of love,MedexcelwithRav

Cognitive bias is a phenomenon in Medicine that has existed for centuries. In this short article, I cover how you shouldn’t believe everything you think and work through ways to reduce clinical diagnostic errors: so you can be the genius FY1 on the wards!