Part three of a series. See also parts one and two.

Previously, I have suggested that patients should do their best to get their doctors as free from the influences of their biases as possible. In order to do that, patients (and doctors) need to recognize what forces are working against them.

Here’s what negatively influences a doctor’s decision making:

1. They fall behind in clinic. Your doctor may be naturally slow or frequently have to spend extra time with patients who are especially ill or emotionally upset.

2. They have to deal with difficult or demanding patients. Hard not to enter into a defensive, paternalistic posture when too many of these types of patients show up on your schedule.

3. They feel like they don’t have enough time to do a good job. With fewer and fewer resources, doctors are being asked (like everyone) to do more and more.

4. They have to deal with a morass of paperwork in a hopelessly inefficient health care system. The amount of time most doctors must spend justifying their decisions to third-party insurance carriers is growing at an alarming rate.

Here’s a sampling of unconscious biases that influence doctor behavior:

1. Not wanting to diagnose bad illnesses in their patients. Leading sometimes to an incomplete list of differential diagnoses.

2. Not wanting to induce anxiety in their patients. Leading sometimes to insufficient explanations of their thought processes, which often paradoxically leads to more patient anxiety.

3. Over-relying on evidence-based medicine. Though the practice of evidence-based medicine should be the standard, many physicians forget there’s a great difference between “there’s no evidence existing in the medical literature to link symptom X with disease Y,” and, “there’s no evidence existing to link symptom X with disease Y because it’s not yet been studied.”

4. Not liking their patient. Leading to impatience, not listening, and not taking enough time to think though the patient’s complaints.

5. Liking their patient too much. Leading to biases #1 and #2.

6. Thinking a patient’s symptoms are caused by one diagnosis instead of many. Also known as Occam’s razor , sometimes it’s true and sometimes it isn’t.

7. Wanting to be right more than wanting their patient to get better. Res ipsa loquitur (the thing speaks for itself).

8. Believing their first thoughts about the diagnosis are more likely to be correct than any subsequent thoughts. If your doctor is too attached to a diagnosis simply because it’s the one he or she thought of first or has seen more than other, less common diagnoses, he or she may avoid pursuing other possibilities.

9. Failing to consider that a test result may be in error. This doesn’t happen commonly, but it certainly does happen.

10. Wanting to avoid feeling ineffectual. Some diagnoses are more amenable to therapy than others. No patient wants to have an untreatable illness and no doctor wants to diagnose it.

11. Having an aversion to being manipulated. Manipulation is especially common in patients suffering from chronic pain syndromes (who may at times appear drug-seeking rather than pain relief-seeking). No one likes to be manipulated, but a wise mentor of mine once said, “The question isn’t whether or not your patients will try to manipulate you. The question is how will they try to manipulate you.” Coming to terms with this truth is vital for any doctor to have successful relationships with their patients.

Alex Lickerman is an internal medicine physician at the University of Chicago who blogs at Happiness in this World.  He is the author of The Undefeated Mind: On the Science of Constructing an Indestructible Self.