Wednesday, July 5, 2023

Bayesian Implications for Factitious Disorder

The next time you encounter a patient with an odd constellation of rare or poorly defined diseases (POTS and MCAS is a common duo), especially if a psychogenic one is on the list (e.g., PNES - not, I presume, intended to be sounded out, as it was proposed as a less offensive alternative to pseudoseizures), do yourself a favor and read one of Mark Feldman's excellent books on factitious disorder, such as the most recent, Dying to Be Ill.

These patients are wellsprings of iatrogenesis, but it is a special variety because the patients actively deceive physicians into unwittingly fostering complications through well-intentioned attempts to diagnose and treat disease. Several biases in medical decision making are exploited by patients with factitious disorder (and its close sibling, malingering, where the reward for the sick role is external - e.g., relief from work, military service or thwarting criminal justice proceedings - rather than internal), and I address some of them in this post.