marginal impact on health being unaffected by one’s level of physical activity. Under these
conditions, — is negative, indicating that the net effect of bad health news is to reduce
∂η
behaviors that compromise health. Individuals will adjust to bad health news by making
healthier diet and lifestyle choices.
∂B
To sign the derivative----for a typical individual, we again rely on the implicit function
∂M
theorem,
P
∂B
∂M
FB
U H +U (H )2 - M (U H +U H +H U H )
H MM HH M BH M H BM B HH M
____________________PB_____________________________
P ...
U H +H U - M (U +2U H +U H +U (H )2)
H MB M HB BB BH B H BB HH B
PB
∂B
Under the same conditions imposed on partial derivatives and cross partials,----is positive. In
∂M
effect, medicine makes it easier to return to behaviors that compromise health. The impact of
making health benefits possible from pharmaceuticals means that many will forego some, or all,
of the possible health benefits. They will make themselves better off by returning to less healthy
diet and lifestyles. This means that some individuals will find they improve their overall well-
being by taking medication while also choosing diets and lifestyles that are less healthful than
they would choose if they had to rely on diet and lifestyle alone to manage a diet-related disease.
∂B
Showing that---> 0 also reveals how unlikely are health impacts predicted from
∂M
pharmaceutical trials alone. A pharmaceutical company would be tempted to promote new
medications (point to large health benefits), making epidemiological predictions by extrapolating
10