How would you put addiction into a mathematical equation?

Been thinking about this, and here’s how I see it.

The variables are as follows, I will use smoking as an example, but this can be used for anything.

W = want for addictive substance/behavior, in this case cigarettes
U = use of addictive substance/behavior, i.e. smoking
C = [negative] consequences of add. sub/beh. – i.e. cancer

Assuming the following set of equations is true….

W=U (want equals, or leads to use)
U=C (use equals, or leads to negative consequences)

then W=C, logically this would mean that a smoker wants to get cancer. But for most smokers this is not the case. What is missing is the variable of D, denial, a crucial component to addiction. So in the addicts mind there is this hidden variable throwing the equation off

it really looks like
W+D !=(does not equal) C

Subtracting denial from the equation, then the want for cigarettes would equal the negative consequences, and the logic will be restored. Therefore, all variables will be set to zero,
W=U=C=0
This person has no want for the substance, doesn’t use it because of this, and avoids the negative consequences involved.

I would like to see what kinds of equations you can come up with, or if you think mine is good.