How Medicine Harms Health: Lessons from Perverse Tradeoffs in Driving

It has been well established that seat belts and other car safety equipment make people drive more recklessly than they would otherwise. The thought process is as follows. Drivers know that seat belts severely cut their risk of death and serious injury in a high-speed collision. Drivers who adopt the seat belt feel safer while wearing one.

Then, completely rationally, the drivers using seatbelts shift their "danger curve" down from the blue curve to the red one. Since for each trip your need to get somewhere is pretty much constant (excluding Sunday drives), it can be represented by a straight line, its scale on the right green axis.

This shifts the no seatbelt optimal trade off between driving speed, danger, and the need to get somewhere -- point A (the intersection between BLUE and GREEN) -- to the seatbelt optimum at point B (RED AND GREEN).

Point A corresponds to a speed of X and point B to a speed of Y. Y is greater than X, meaning people who drive with seat belts drive faster than they would without the safety restraints. If we use speed as a proxy for general recklessness, then we have proved my assertion. One would find similar results if we used percentage of brain devoted to driving instead of speed, but where the data would come from is beyond the scope of this blog.

Likewise, people face exposure to similar safety devices in other aspects of their daily lives: drugs and medicine. Consider replacing a constant "desire to live" as the GREEN line. If the horizontal axis represents the healthiness of a person's lifestyle, what effect would a similar shifting of the danger curve result in? A less healthy lifestyle filled with bad short term tradeoffs with the hope that medicine will save them in the long run.