Describes habituation and addiction, both psychological and physiological, using the simple equations of the mathematical model of ideodynamics. The parameters in these equations were optimized to smoking data from the Multiple Risk Factor Intervention Trial (MRFIT) program. With only 4 constant parameters, it was possible to calculate accurate time trends for recidivism to smoking among quitters, time trends for secondary cessation among recidivists, and final percentage of smokers in a population with both recidivism and secondary cessation occurring simultaneously. These same parameters further permit predictions for the long-range success of intervention programs to decrease substance dependency. Ideodynamics can also predict time trends of public opinion based on stories in the mass media.