Determining whether a patient is feeling better: pitfalls from the science of human perception.

Human perception is fallible and may lead patients to be inaccurate when judging whether their symptoms are improving with treatment. This article provides a narrative review of studies in psychology that describe misconceptions related to a patient's comprehension, recall, evaluation and expression. The specific misconceptions include the power of suggestion (placebo effects), desire for peace-of-mind (cognitive dissonance reduction), inconsistent standards (loss aversion), a flawed sense of time (duration neglect), limited perception (measurement error), declining sensitivity (Weber's law), an eagerness to please (social desirability bias), and subtle affirmation (personal control). An awareness of specific pitfalls might help clinicians avoid some mistakes when providing follow-up and interpreting changes in patient symptoms.