9 Common Cognitive Biases by Physicians That Can Prevent a Mold or Environmental Illness Diagnosis

By Cesar Collado

A cognitive bias is mistake in reasoning, evaluating, remembering, or other thinking processes that may prejudice or steer a decision toward an inaccurate conclusion.  We all have cognitive biases and they influence our decision making.  This article is meant to focus on specific cognitive biases that can be experienced by physicians that specifically impact medical decisions with mold sufferers.

Physicians invest a more than a decade into training for a chosen specialty and work extremely hard to be able to practice medicine. In doing so, they face the following challenges:

  • Consuming vast amounts of scientific and clinical information and having the capacity to tap into this information at any moment;
  • Passing medical examinations (Boards) to be licensed to practice, and repeat testing to stay licensed and up-to-date in their specialty;
  • Staying current, although science and medicine in today’s information technology age and the ease to publish make it virtually impossible to keep up with all new information;
  • Keeping up with demanding schedules and limited time per patient.

Because of the burdens placed on them, they face several cognitive biases that challenge their effectiveness.  Cognitive biases are systematic errors in thinking that affects the decisions and judgments that are possessed by all of us. Biases can be based on memory, complexity, routine, focus, position, time pressure, or ego.

Physicians, however, when making judgments and decisions about their patients, have every reason to believe they are objective, logical, and fully capable of taking in and evaluating all the information that is available to them. Unfortunately, an unlimited volume of information and cognitive biases sometimes trip us all up, leading to poor decisions and bad judgments.

The following are a subset of  several cognitive biases that occur in physicians with examples to better prepare environmental illness patients in describing their illness and symptoms.  

  1. Anchoring: The tendency to perceptually lock on to salient features in the patient’s initial presentation too early in the diagnostic process, and failure to adjust this initial impression in the light of later information. 

Example:  It is flue season and you see your doctor for sinus, headache, and mucous.  During this visit, you mention that you are experiencing GERD or reflux.  The family physician anchors by treating you for flu-like symptoms.   The physician suggest OTC medications for  reflux without considering whether the GERD is related to your sinusitis because of candida overgrowth. Read More… 

  1. Attribution Error: A form of stereotyping: explaining a patient’s condition on the basis of their disposition or character rather than seeking a valid medical explanation.


Environmental Example:  A frequent visiting patient or “thick chart” patient visits a new physician complaining about severe illness similar to symptoms presented before to another practice physician. The physician prescribes similar treatment with modifications, even though the previous treatment didn’t work.  A new diagnosis is not explored.

  1. Authority Bias: Declining to disagree with an “expert.”

Environmental Example: A patient who has suffered from acute sinusitis who has seen by an ENT within the healthcare system who has been treated with antibiotics and steroids presents a general practitioner with additional symptoms (fatigue, inflammation, and mucous production).  The physician does not ask questions about the patient history of sinusitis and quickly confirms bacterial sinusitis and prescribes another antibiotic or steroid.

  1. Availability Heuristic Bias: Recent or vivid patient diagnoses are more easily brought to mind (i.e. are more available to memory) and overemphasized in assessing the probability of a current diagnosis. A heuristic is a mental shortcut.

Environmental Example: A patient with fever and myalgia who has a history of arthritis sees a physician and is immediately treated for arthritis with a treatment alternative vs. further investigation for viral, bacterial, or other environmental causes.

  1. Confirmation Bias: The tendency to look for confirming evidence to support a diagnosis rather than look for disconfirming evidence to refute it, despite the latter often being more persuasive and definitive.

Environmental Example:  You present your physician with chronic headaches. The doctor diagnoses a migraine and asks only questions regarding the headache pain and description. They prescribe migraine treatment medication without asking about sinus symptoms or history of respiratory illness.

  1. Ego Bias: In medicine, this is when a physician systematically overestimates the prognosis of one’s own patients compared with that of a population of similar patients.

Environmental Example:  A patient presents the physician with symptoms of pain, fatigue, and inability to function.  The physician diagnosis a disease of exclusion (Depression, Fibromyalgia or Chronic Fatigue) without additional diagnostics or consideration of the environment. The patient may receive medication such as antidepressants or anticonvulsants for pain.

  1. Premature Closure: It is the tendency to apply premature closure to the decision-making process, accepting a diagnosis before it has been fully verified. The consequences of the bias are reflected in the “when the diagnosis is made, the thinking stops.”This is a powerful bias accounting for a high proportion of missed diagnoses.

Environmental Example:  A patient presents a physician with pain in any form with other symptoms.  As a result, the physician treats the pain without investigating medical history, other causes, or the environment to determine the cause.

  1. Search Satisfaction:  The tendency to call off a search once something is found. It is pervasive and considered one of the most important sources of error.

Environmental Example:  A patient sees a doctor with severe fatigue, headaches, inflammation, and significant gastrointestinal issues. The doctor quickly diagnoses food poisoning without investigating medical history or considering the environment.

  1. Zebra Retreat: This bias occurs when a rare diagnosis (zebra) figures prominently on the differential diagnosis but the physician retreats from it for various reasons:
  • Insurance barriers to obtaining special or costly tests
  • Underestimating or overestimating the base-rate for the diagnosis
  • The clinical environment may be very busy and the anticipated time and effort to pursue the diagnosis might dilute the physician’s conviction
  • Administration may exert coercive pressure to avoid wasting the team’s time
  • Inconvenience of the time of day or weekend and difficulty getting access to specialists
  • Unfamiliarity with the diagnosis might make the physician less likely to go down an unfamiliar road
  • Fatigue, sleep deprivation, or other distractions may tip the physician toward retreat

Any one or a combination of these reasons may result in a failure to pursue the initial hypothesis.

Environmental Example: A patient suffering from chronic fatigue, brain fog, inactivity, insomnia and inability to work AND that patient suggests mold. The physician asks few medical history questions or questions about the environment, diagnoses depression, and prescribes an antidepressant rather than considering the environment or referring the patient to a specialist. 

Prospect Theory/Loss Avoidance

There are many more cognitive biases we are all susceptible to. Perhaps the most profound is Prospect Theory.  A Phycologists named Daniel Kahneman won the 2002 Nobel Prize for Economics for his decision science work on Prospect theory.  To simplify, all of us place a greater weight on loss, however, this forces us to focus on the positive outcome of situation.  This can be simply explained by two examples:

  • Some people purchase lottery tickets regardless of the probability of winning or whether it is the best use of available funding;
  • Alternatively, some people will pay whatever they need to for health insurance, because the threat of a catastrophic illness and bankruptcy far outweighs the cost of the insurance.

For Mold Sensitive and Environmental Illness Sufferers

Because environmental illness and mold are only briefly covered in as little as one day during 10-12 years of medical training, it is not surprising that most traditional general and specialist physicians may normally be predisposed to cognitive biases when faced with a patient suffering from environmental illness during their regular practice.  In addition, there are other contributing factors:

  • The inability for any physician to review all of the available literature across all disease states. The sheer volume of literature during the electronic data age makes this impossible.
  • The healthcare system only allows for limited time with patients.Physicians do not have time to fully study the patient’s chart and medical history. They cannot explore every alternative and may not explore situations for which they do not see or do not have an immediate view of, such as the home environment.

What Patients Who Believe Mold is the Cause Can Do Immediately and Inexpensively 

Because of these limitations, the burden falls on the patient to do their homework if they suspect environmental illness.  This is more obvious than we believe, because most environmental patients have a long history with their illness and have seen numerous physicians and tried numerous medications without success. Patients can mitigate the risk of encountering these cognitive biases by considering these suggestions:

Research local physicians and seek those who treat environmental illness. For screening purposes, the following actions are helpful”

  • Google “doctors who treat environmental illness;”
  • Research these physician websites to attempt to find a provider that understands mold and treats environmental illness;
  • Call ahead to ask questions about environmental illness in the practice and inquire about how much time the physician spends with patients.

Patients can do experimentation on their own by exploring their home and work environments for mold. By doing this, they can “Take Mold off the Table” much more inexpensively as well as have a conclusive piece of information that will make them feel better. Or, if mold is found, they have environmental evidence to take to the physician for a more accurate diagnosis. Ways to conduct this type of experimentation include:

  • Using EC3 Mold TestingPlates to test their home, office, car, etc. for mold;
  • Spending a few days away from their home or office to see if they feel better.

Patients can also do a remediation experiment to determine if the cause of their illness is mold. By reducing the fungal load of mold spores in their home air, they can determine if they feel better.  This is a home experiment and should not be confused with a medical experiment. Taking the following actions will reduce indoor fungal loads:

Patients can also rev up their immune systems to handle mold allergens more effectively to see if they feel better sooner. A few actions to do this include:

  • Using Sinus Defenseto help the body identify and employ the immediate cell-mediated immunity that eliminates mold antigens in the system;
  • Supporting the pituitary and hormonal systems with CellTropinto help the body heal from mold exposure.

If doing any of the above makes a patient feel better, they can fairly conclude that mold is causing their illness and be better prepared to clearly present mold their health issue to their doctors.

Just remember, we all have cognitive biases such as believing our physicians do not ever make mistakes (Authority Bias). Learning about these biases is tremendously helpful in finding wellness from mold illness.

  1. Croskerry, Pat, MD, PhD, FRCP(Edin), “50 Cognitive and Affective Biases in Medicine” Critical Thinking Program, Dalhousie University, May 2013
  2. Kahneman, Daniel, Ph.D. Wikipedia profile. https://en.wikipedia.org/wiki/Daniel_Kahneman
  3. Common Cognitive Biases. CMPA Common Practices Guide.  Canadian Medical Protection Association (CMPA)
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